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2020-10-13mm,kmemleak-test.c: move kmemleak-test.c to samples dirHui Su
kmemleak-test.c is just a kmemleak test module, which also can not be used as a built-in kernel module. Thus, i think it may should not be in mm dir, and move the kmemleak-test.c to samples/kmemleak/kmemleak-test.c. Fix the spelling of built-in by the way. Signed-off-by: Hui Su <sh_def@163.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Cc: David S. Miller <davem@davemloft.net> Cc: Rob Herring <robh@kernel.org> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> Cc: Divya Indi <divya.indi@oracle.com> Cc: Tomas Winkler <tomas.winkler@intel.com> Cc: David Howells <dhowells@redhat.com> Link: https://lkml.kernel.org/r/20200925183729.GA172837@rlk Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07mm: move lib/ioremap.c to mm/Mike Rapoport
The functionality in lib/ioremap.c deals with pagetables, vmalloc and caches, so it naturally belongs to mm/ Moving it there will also allow declaring p?d_alloc_track functions in an header file inside mm/ rather than having those declarations in include/linux/mm.h Suggested-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Pekka Enberg <penberg@kernel.org> Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Joerg Roedel <joro@8bytes.org> Cc: Joerg Roedel <jroedel@suse.de> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com> Cc: Stafford Horne <shorne@gmail.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Matthew Wilcox <willy@infradead.org> Link: http://lkml.kernel.org/r/20200627143453.31835-8-rppt@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-11Merge tag 'locking-kcsan-2020-06-11' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull the Kernel Concurrency Sanitizer from Thomas Gleixner: "The Kernel Concurrency Sanitizer (KCSAN) is a dynamic race detector, which relies on compile-time instrumentation, and uses a watchpoint-based sampling approach to detect races. The feature was under development for quite some time and has already found legitimate bugs. Unfortunately it comes with a limitation, which was only understood late in the development cycle: It requires an up to date CLANG-11 compiler CLANG-11 is not yet released (scheduled for June), but it's the only compiler today which handles the kernel requirements and especially the annotations of functions to exclude them from KCSAN instrumentation correctly. These annotations really need to work so that low level entry code and especially int3 text poke handling can be completely isolated. A detailed discussion of the requirements and compiler issues can be found here: https://lore.kernel.org/lkml/CANpmjNMTsY_8241bS7=XAfqvZHFLrVEkv_uM4aDUWE_kh3Rvbw@mail.gmail.com/ We came to the conclusion that trying to work around compiler limitations and bugs again would end up in a major trainwreck, so requiring a working compiler seemed to be the best choice. For Continous Integration purposes the compiler restriction is manageable and that's where most xxSAN reports come from. For a change this limitation might make GCC people actually look at their bugs. Some issues with CSAN in GCC are 7 years old and one has been 'fixed' 3 years ago with a half baken solution which 'solved' the reported issue but not the underlying problem. The KCSAN developers also ponder to use a GCC plugin to become independent, but that's not something which will show up in a few days. Blocking KCSAN until wide spread compiler support is available is not a really good alternative because the continuous growth of lockless optimizations in the kernel demands proper tooling support" * tag 'locking-kcsan-2020-06-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (76 commits) compiler_types.h, kasan: Use __SANITIZE_ADDRESS__ instead of CONFIG_KASAN to decide inlining compiler.h: Move function attributes to compiler_types.h compiler.h: Avoid nested statement expression in data_race() compiler.h: Remove data_race() and unnecessary checks from {READ,WRITE}_ONCE() kcsan: Update Documentation to change supported compilers kcsan: Remove 'noinline' from __no_kcsan_or_inline kcsan: Pass option tsan-instrument-read-before-write to Clang kcsan: Support distinguishing volatile accesses kcsan: Restrict supported compilers kcsan: Avoid inserting __tsan_func_entry/exit if possible ubsan, kcsan: Don't combine sanitizer with kcov on clang objtool, kcsan: Add kcsan_disable_current() and kcsan_enable_current_nowarn() kcsan: Add __kcsan_{enable,disable}_current() variants checkpatch: Warn about data_race() without comment kcsan: Use GFP_ATOMIC under spin lock Improve KCSAN documentation a bit kcsan: Make reporting aware of KCSAN tests kcsan: Fix function matching in report kcsan: Change data_race() to no longer require marking racing accesses kcsan: Move kcsan_{disable,enable}_current() to kcsan-checks.h ...
2020-06-11Rebase locking/kcsan to locking/urgentThomas Gleixner
Merge the state of the locking kcsan branch before the read/write_once() and the atomics modifications got merged. Squash the fallout of the rebase on top of the read/write once and atomic fallback work into the merge. The history of the original branch is preserved in tag locking-kcsan-2020-06-02. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2020-06-10kernel: move use_mm/unuse_mm to kthread.cChristoph Hellwig
Patch series "improve use_mm / unuse_mm", v2. This series improves the use_mm / unuse_mm interface by better documenting the assumptions, and my taking the set_fs manipulations spread over the callers into the core API. This patch (of 3): Use the proper API instead. Link: http://lkml.kernel.org/r/20200404094101.672954-1-hch@lst.de These helpers are only for use with kernel threads, and I will tie them more into the kthread infrastructure going forward. Also move the prototypes to kthread.h - mmu_context.h was a little weird to start with as it otherwise contains very low-level MM bits. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Jens Axboe <axboe@kernel.dk> Reviewed-by: Jens Axboe <axboe@kernel.dk> Acked-by: Felix Kuehling <Felix.Kuehling@amd.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Felipe Balbi <balbi@kernel.org> Cc: Jason Wang <jasowang@redhat.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Zhenyu Wang <zhenyuw@linux.intel.com> Cc: Zhi Wang <zhi.a.wang@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: http://lkml.kernel.org/r/20200404094101.672954-1-hch@lst.de Link: http://lkml.kernel.org/r/20200416053158.586887-1-hch@lst.de Link: http://lkml.kernel.org/r/20200404094101.672954-5-hch@lst.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-04mm/debug: add tests validating architecture page table helpersAnshuman Khandual
This adds tests which will validate architecture page table helpers and other accessors in their compliance with expected generic MM semantics. This will help various architectures in validating changes to existing page table helpers or addition of new ones. This test covers basic page table entry transformations including but not limited to old, young, dirty, clean, write, write protect etc at various level along with populating intermediate entries with next page table page and validating them. Test page table pages are allocated from system memory with required size and alignments. The mapped pfns at page table levels are derived from a real pfn representing a valid kernel text symbol. This test gets called via late_initcall(). This test gets built and run when CONFIG_DEBUG_VM_PGTABLE is selected. Any architecture, which is willing to subscribe this test will need to select ARCH_HAS_DEBUG_VM_PGTABLE. For now this is limited to arc, arm64, x86, s390 and powerpc platforms where the test is known to build and run successfully Going forward, other architectures too can subscribe the test after fixing any build or runtime problems with their page table helpers. Folks interested in making sure that a given platform's page table helpers conform to expected generic MM semantics should enable the above config which will just trigger this test during boot. Any non conformity here will be reported as an warning which would need to be fixed. This test will help catch any changes to the agreed upon semantics expected from generic MM and enable platforms to accommodate it thereafter. [anshuman.khandual@arm.com: v17] Link: http://lkml.kernel.org/r/1587436495-22033-3-git-send-email-anshuman.khandual@arm.com [anshuman.khandual@arm.com: v18] Link: http://lkml.kernel.org/r/1588564865-31160-3-git-send-email-anshuman.khandual@arm.com Suggested-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> [s390] Tested-by: Christophe Leroy <christophe.leroy@c-s.fr> [ppc32] Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Link: http://lkml.kernel.org/r/1583919272-24178-1-git-send-email-anshuman.khandual@arm.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-13Merge tag 'v5.7-rc1' into locking/kcsan, to resolve conflicts and refreshIngo Molnar
Resolve these conflicts: arch/x86/Kconfig arch/x86/kernel/Makefile Do a minor "evil merge" to move the KCSAN entry up a bit by a few lines in the Kconfig to reduce the probability of future conflicts. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-07mm: introduce Reported pagesAlexander Duyck
In order to pave the way for free page reporting in virtualized environments we will need a way to get pages out of the free lists and identify those pages after they have been returned. To accomplish this, this patch adds the concept of a Reported Buddy, which is essentially meant to just be the Uptodate flag used in conjunction with the Buddy page type. To prevent the reported pages from leaking outside of the buddy lists I added a check to clear the PageReported bit in the del_page_from_free_list function. As a result any reported page that is split, merged, or allocated will have the flag cleared prior to the PageBuddy value being cleared. The process for reporting pages is fairly simple. Once we free a page that meets the minimum order for page reporting we will schedule a worker thread to start 2s or more in the future. That worker thread will begin working from the lowest supported page reporting order up to MAX_ORDER - 1 pulling unreported pages from the free list and storing them in the scatterlist. When processing each individual free list it is necessary for the worker thread to release the zone lock when it needs to stop and report the full scatterlist of pages. To reduce the work of the next iteration the worker thread will rotate the free list so that the first unreported page in the free list becomes the first entry in the list. It will then call a reporting function providing information on how many entries are in the scatterlist. Once the function completes it will return the pages to the free area from which they were allocated and start over pulling more pages from the free areas until there are no longer enough pages to report on to keep the worker busy, or we have processed as many pages as were contained in the free area when we started processing the list. The worker thread will work in a round-robin fashion making its way though each zone requesting reporting, and through each reportable free list within that zone. Once all free areas within the zone have been processed it will check to see if there have been any requests for reporting while it was processing. If so it will reschedule the worker thread to start up again in roughly 2s and exit. Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Nitesh Narayan Lal <nitesh@redhat.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pankaj Gupta <pagupta@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Wang <wei.w.wang@intel.com> Cc: Yang Zhang <yang.zhang.wz@gmail.com> Cc: wei qi <weiqi4@huawei.com> Link: http://lkml.kernel.org/r/20200211224635.29318.19750.stgit@localhost.localdomain Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-02mm/Makefile: disable KCSAN for kmemleakQian Cai
Kmemleak could scan task stacks while plain writes happens to those stack variables which could results in data races. For example, in sys_rt_sigaction and do_sigaction(), it could have plain writes in a 32-byte size. Since the kmemleak does not care about the actual values of a non-pointer and all do_sigaction() call sites only copy to stack variables, just disable KCSAN for kmemleak to avoid annotating anything outside Kmemleak just because Kmemleak scans everything. Suggested-by: Marco Elver <elver@google.com> Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Marco Elver <elver@google.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Link: http://lkml.kernel.org/r/1583263716-25150-1-git-send-email-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-03-21Merge branch 'x86/kdump' into locking/kcsan, to resolve conflictsIngo Molnar
Conflicts: arch/x86/purgatory/Makefile Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-02-04mm: add generic ptdumpSteven Price
Add a generic version of page table dumping that architectures can opt-in to. Link: http://lkml.kernel.org/r/20191218162402.45610-20-steven.price@arm.com Signed-off-by: Steven Price <steven.price@arm.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Andy Lutomirski <luto@kernel.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Hogan <jhogan@kernel.org> Cc: James Morse <james.morse@arm.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: "Liang, Kan" <kan.liang@linux.intel.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Burton <paul.burton@mips.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Cc: Zong Li <zong.li@sifive.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-31kcov: ignore fault-inject and stacktraceDmitry Vyukov
Don't instrument 3 more files that contain debugging facilities and produce large amounts of uninteresting coverage for every syscall. The following snippets are sprinkled all over the place in kcov traces in a debugging kernel. We already try to disable instrumentation of stack unwinding code and of most debug facilities. I guess we did not use fault-inject.c at the time, and stacktrace.c was somehow missed (or something has changed in kernel/configs). This change both speeds up kcov (kernel doesn't need to store these PCs, user-space doesn't need to process them) and frees trace buffer capacity for more useful coverage. should_fail lib/fault-inject.c:149 fail_dump lib/fault-inject.c:45 stack_trace_save kernel/stacktrace.c:124 stack_trace_consume_entry kernel/stacktrace.c:86 stack_trace_consume_entry kernel/stacktrace.c:89 ... a hundred frames skipped ... stack_trace_consume_entry kernel/stacktrace.c:93 stack_trace_consume_entry kernel/stacktrace.c:86 Link: http://lkml.kernel.org/r/20200116111449.217744-1-dvyukov@gmail.com Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-30Merge tag 'v5.5-rc4' into locking/kcsan, to resolve conflictsIngo Molnar
Conflicts: init/main.c lib/Kconfig.debug Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-11-16build, kcsan: Add KCSAN build exceptionsMarco Elver
This blacklists several compilation units from KCSAN. See the respective inline comments for the reasoning. Signed-off-by: Marco Elver <elver@google.com> Acked-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-11-06mm: Add write-protect and clean utilities for address space rangesThomas Hellstrom
Add two utilities to 1) write-protect and 2) clean all ptes pointing into a range of an address space. The utilities are intended to aid in tracking dirty pages (either driver-allocated system memory or pci device memory). The write-protect utility should be used in conjunction with page_mkwrite() and pfn_mkwrite() to trigger write page-faults on page accesses. Typically one would want to use this on sparse accesses into large memory regions. The clean utility should be used to utilize hardware dirtying functionality and avoid the overhead of page-faults, typically on large accesses into small memory regions. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Will Deacon <will.deacon@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> Acked-by: Andrew Morton <akpm@linux-foundation.org>
2019-09-24mm: silence -Woverride-init/initializer-overridesQian Cai
When compiling a kernel with W=1, there are several of those warnings due to arm64 overriding a field on purpose. Just disable those warnings for both GCC and Clang of this file, so it will help dig "gems" hidden in the W=1 warnings by reducing some noises. mm/init-mm.c:39:2: warning: initializer overrides prior initialization of this subobject [-Winitializer-overrides] INIT_MM_CONTEXT(init_mm) ^~~~~~~~~~~~~~~~~~~~~~~~ ./arch/arm64/include/asm/mmu.h:133:9: note: expanded from macro 'INIT_MM_CONTEXT' .pgd = init_pg_dir, ^~~~~~~~~~~ mm/init-mm.c:30:10: note: previous initialization is here .pgd = swapper_pg_dir, ^~~~~~~~~~~~~~ Note: there is a side project trying to support explicitly allowing specific initializer overrides in Clang, but there is no guarantee it will happen or not. https://github.com/ClangBuiltLinux/linux/issues/639 Link: http://lkml.kernel.org/r/1566920867-27453-1-git-send-email-cai@lca.pw Signed-off-by: Qian Cai <cai@lca.pw> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-24mm: remove quicklist page table cachesNicholas Piggin
Patch series "mm: remove quicklist page table caches". A while ago Nicholas proposed to remove quicklist page table caches [1]. I've rebased his patch on the curren upstream and switched ia64 and sh to use generic versions of PTE allocation. [1] https://lore.kernel.org/linux-mm/20190711030339.20892-1-npiggin@gmail.com This patch (of 3): Remove page table allocator "quicklists". These have been around for a long time, but have not got much traction in the last decade and are only used on ia64 and sh architectures. The numbers in the initial commit look interesting but probably don't apply anymore. If anybody wants to resurrect this it's in the git history, but it's unhelpful to have this code and divergent allocator behaviour for minor archs. Also it might be better to instead make more general improvements to page allocator if this is still so slow. Link: http://lkml.kernel.org/r/1565250728-21721-2-git-send-email-rppt@linux.ibm.com Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-03memremap: move from kernel/ to mm/Christoph Hellwig
memremap.c implements MM functionality for ZONE_DEVICE, so it really should be in the mm/ directory, not the kernel/ one. Link: http://lkml.kernel.org/r/20190722094143.18387-1-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Acked-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-14Merge tag 'for-linus-hmm' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma Pull HMM updates from Jason Gunthorpe: "Improvements and bug fixes for the hmm interface in the kernel: - Improve clarity, locking and APIs related to the 'hmm mirror' feature merged last cycle. In linux-next we now see AMDGPU and nouveau to be using this API. - Remove old or transitional hmm APIs. These are hold overs from the past with no users, or APIs that existed only to manage cross tree conflicts. There are still a few more of these cleanups that didn't make the merge window cut off. - Improve some core mm APIs: - export alloc_pages_vma() for driver use - refactor into devm_request_free_mem_region() to manage DEVICE_PRIVATE resource reservations - refactor duplicative driver code into the core dev_pagemap struct - Remove hmm wrappers of improved core mm APIs, instead have drivers use the simplified API directly - Remove DEVICE_PUBLIC - Simplify the kconfig flow for the hmm users and core code" * tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (42 commits) mm: don't select MIGRATE_VMA_HELPER from HMM_MIRROR mm: remove the HMM config option mm: sort out the DEVICE_PRIVATE Kconfig mess mm: simplify ZONE_DEVICE page private data mm: remove hmm_devmem_add mm: remove hmm_vma_alloc_locked_page nouveau: use devm_memremap_pages directly nouveau: use alloc_page_vma directly PCI/P2PDMA: use the dev_pagemap internal refcount device-dax: use the dev_pagemap internal refcount memremap: provide an optional internal refcount in struct dev_pagemap memremap: replace the altmap_valid field with a PGMAP_ALTMAP_VALID flag memremap: remove the data field in struct dev_pagemap memremap: add a migrate_to_ram method to struct dev_pagemap_ops memremap: lift the devmap_enable manipulation into devm_memremap_pages memremap: pass a struct dev_pagemap to ->kill and ->cleanup memremap: move dev_pagemap callbacks into a separate structure memremap: validate the pagemap type passed to devm_memremap_pages mm: factor out a devm_request_free_mem_region helper mm: export alloc_pages_vma ...
2019-07-12mm: consolidate the get_user_pages* implementationsChristoph Hellwig
Always build mm/gup.c so that we don't have to provide separate nommu stubs. Also merge the get_user_pages_fast and __get_user_pages_fast stubs when HAVE_FAST_GUP into the main implementations, which will never call the fast path if HAVE_FAST_GUP is not set. This also ensures the new put_user_pages* helpers are available for nommu, as those are currently missing, which would create a problem as soon as we actually grew users for it. Link: http://lkml.kernel.org/r/20190625143715.1689-13-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Miller <davem@davemloft.net> Cc: James Hogan <jhogan@kernel.org> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Khalid Aziz <khalid.aziz@oracle.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Rich Felker <dalias@libc.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-02mm: remove the HMM config optionChristoph Hellwig
All the mm/hmm.c code is better keyed off HMM_MIRROR. Also let nouveau depend on it instead of the mix of a dummy dependency symbol plus the actually selected one. Drop various odd dependencies, as the code is pretty portable. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-05-14mm: shuffle initial free memory to improve memory-side-cache utilizationDan Williams
Patch series "mm: Randomize free memory", v10. This patch (of 3): Randomization of the page allocator improves the average utilization of a direct-mapped memory-side-cache. Memory side caching is a platform capability that Linux has been previously exposed to in HPC (high-performance computing) environments on specialty platforms. In that instance it was a smaller pool of high-bandwidth-memory relative to higher-capacity / lower-bandwidth DRAM. Now, this capability is going to be found on general purpose server platforms where DRAM is a cache in front of higher latency persistent memory [1]. Robert offered an explanation of the state of the art of Linux interactions with memory-side-caches [2], and I copy it here: It's been a problem in the HPC space: http://www.nersc.gov/research-and-development/knl-cache-mode-performance-coe/ A kernel module called zonesort is available to try to help: https://software.intel.com/en-us/articles/xeon-phi-software and this abandoned patch series proposed that for the kernel: https://lkml.kernel.org/r/20170823100205.17311-1-lukasz.daniluk@intel.com Dan's patch series doesn't attempt to ensure buffers won't conflict, but also reduces the chance that the buffers will. This will make performance more consistent, albeit slower than "optimal" (which is near impossible to attain in a general-purpose kernel). That's better than forcing users to deploy remedies like: "To eliminate this gradual degradation, we have added a Stream measurement to the Node Health Check that follows each job; nodes are rebooted whenever their measured memory bandwidth falls below 300 GB/s." A replacement for zonesort was merged upstream in commit cc9aec03e58f ("x86/numa_emulation: Introduce uniform split capability"). With this numa_emulation capability, memory can be split into cache sized ("near-memory" sized) numa nodes. A bind operation to such a node, and disabling workloads on other nodes, enables full cache performance. However, once the workload exceeds the cache size then cache conflicts are unavoidable. While HPC environments might be able to tolerate time-scheduling of cache sized workloads, for general purpose server platforms, the oversubscribed cache case will be the common case. The worst case scenario is that a server system owner benchmarks a workload at boot with an un-contended cache only to see that performance degrade over time, even below the average cache performance due to excessive conflicts. Randomization clips the peaks and fills in the valleys of cache utilization to yield steady average performance. Here are some performance impact details of the patches: 1/ An Intel internal synthetic memory bandwidth measurement tool, saw a 3X speedup in a contrived case that tries to force cache conflicts. The contrived cased used the numa_emulation capability to force an instance of the benchmark to be run in two of the near-memory sized numa nodes. If both instances were placed on the same emulated they would fit and cause zero conflicts. While on separate emulated nodes without randomization they underutilized the cache and conflicted unnecessarily due to the in-order allocation per node. 2/ A well known Java server application benchmark was run with a heap size that exceeded cache size by 3X. The cache conflict rate was 8% for the first run and degraded to 21% after page allocator aging. With randomization enabled the rate levelled out at 11%. 3/ A MongoDB workload did not observe measurable difference in cache-conflict rates, but the overall throughput dropped by 7% with randomization in one case. 4/ Mel Gorman ran his suite of performance workloads with randomization enabled on platforms without a memory-side-cache and saw a mix of some improvements and some losses [3]. While there is potentially significant improvement for applications that depend on low latency access across a wide working-set, the performance may be negligible to negative for other workloads. For this reason the shuffle capability defaults to off unless a direct-mapped memory-side-cache is detected. Even then, the page_alloc.shuffle=0 parameter can be specified to disable the randomization on those systems. Outside of memory-side-cache utilization concerns there is potentially security benefit from randomization. Some data exfiltration and return-oriented-programming attacks rely on the ability to infer the location of sensitive data objects. The kernel page allocator, especially early in system boot, has predictable first-in-first out behavior for physical pages. Pages are freed in physical address order when first onlined. Quoting Kees: "While we already have a base-address randomization (CONFIG_RANDOMIZE_MEMORY), attacks against the same hardware and memory layouts would certainly be using the predictability of allocation ordering (i.e. for attacks where the base address isn't important: only the relative positions between allocated memory). This is common in lots of heap-style attacks. They try to gain control over ordering by spraying allocations, etc. I'd really like to see this because it gives us something similar to CONFIG_SLAB_FREELIST_RANDOM but for the page allocator." While SLAB_FREELIST_RANDOM reduces the predictability of some local slab caches it leaves vast bulk of memory to be predictably in order allocated. However, it should be noted, the concrete security benefits are hard to quantify, and no known CVE is mitigated by this randomization. Introduce shuffle_free_memory(), and its helper shuffle_zone(), to perform a Fisher-Yates shuffle of the page allocator 'free_area' lists when they are initially populated with free memory at boot and at hotplug time. Do this based on either the presence of a page_alloc.shuffle=Y command line parameter, or autodetection of a memory-side-cache (to be added in a follow-on patch). The shuffling is done in terms of CONFIG_SHUFFLE_PAGE_ORDER sized free pages where the default CONFIG_SHUFFLE_PAGE_ORDER is MAX_ORDER-1 i.e. 10, 4MB this trades off randomization granularity for time spent shuffling. MAX_ORDER-1 was chosen to be minimally invasive to the page allocator while still showing memory-side cache behavior improvements, and the expectation that the security implications of finer granularity randomization is mitigated by CONFIG_SLAB_FREELIST_RANDOM. The performance impact of the shuffling appears to be in the noise compared to other memory initialization work. This initial randomization can be undone over time so a follow-on patch is introduced to inject entropy on page free decisions. It is reasonable to ask if the page free entropy is sufficient, but it is not enough due to the in-order initial freeing of pages. At the start of that process putting page1 in front or behind page0 still keeps them close together, page2 is still near page1 and has a high chance of being adjacent. As more pages are added ordering diversity improves, but there is still high page locality for the low address pages and this leads to no significant impact to the cache conflict rate. [1]: https://itpeernetwork.intel.com/intel-optane-dc-persistent-memory-operating-modes/ [2]: https://lkml.kernel.org/r/AT5PR8401MB1169D656C8B5E121752FC0F8AB120@AT5PR8401MB1169.NAMPRD84.PROD.OUTLOOK.COM [3]: https://lkml.org/lkml/2018/10/12/309 [dan.j.williams@intel.com: fix shuffle enable] Link: http://lkml.kernel.org/r/154943713038.3858443.4125180191382062871.stgit@dwillia2-desk3.amr.corp.intel.com [cai@lca.pw: fix SHUFFLE_PAGE_ALLOCATOR help texts] Link: http://lkml.kernel.org/r/20190425201300.75650-1-cai@lca.pw Link: http://lkml.kernel.org/r/154899811738.3165233.12325692939590944259.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Qian Cai <cai@lca.pw> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Robert Elliott <elliott@hpe.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-31mm: remove nobootmemMike Rapoport
Move a few remaining functions from nobootmem.c to memblock.c and remove nobootmem Link: http://lkml.kernel.org/r/1536927045-23536-28-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Zankel <chris@zankel.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Ingo Molnar <mingo@redhat.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Jonas Bonn <jonas@southpole.se> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Ley Foon Tan <lftan@altera.com> Cc: Mark Salter <msalter@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Palmer Dabbelt <palmer@sifive.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Serge Semin <fancer.lancer@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-31mm: remove CONFIG_HAVE_MEMBLOCKMike Rapoport
All architecures use memblock for early memory management. There is no need for the CONFIG_HAVE_MEMBLOCK configuration option. [rppt@linux.vnet.ibm.com: of/fdt: fixup #ifdefs] Link: http://lkml.kernel.org/r/20180919103457.GA20545@rapoport-lnx [rppt@linux.vnet.ibm.com: csky: fixups after bootmem removal] Link: http://lkml.kernel.org/r/20180926112744.GC4628@rapoport-lnx [rppt@linux.vnet.ibm.com: remove stale #else and the code it protects] Link: http://lkml.kernel.org/r/1538067825-24835-1-git-send-email-rppt@linux.vnet.ibm.com Link: http://lkml.kernel.org/r/1536927045-23536-4-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Jonathan Cameron <jonathan.cameron@huawei.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Zankel <chris@zankel.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Ingo Molnar <mingo@redhat.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Jonas Bonn <jonas@southpole.se> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Ley Foon Tan <lftan@altera.com> Cc: Mark Salter <msalter@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Palmer Dabbelt <palmer@sifive.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Serge Semin <fancer.lancer@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-31mm: remove CONFIG_NO_BOOTMEMMike Rapoport
All achitectures select NO_BOOTMEM which essentially becomes 'Y' for any kernel configuration and therefore it can be removed. [alexander.h.duyck@linux.intel.com: remove now defunct NO_BOOTMEM from depends list for deferred init] Link: http://lkml.kernel.org/r/20180925201814.3576.15105.stgit@localhost.localdomain Link: http://lkml.kernel.org/r/1536927045-23536-3-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Zankel <chris@zankel.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Ingo Molnar <mingo@redhat.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Jonas Bonn <jonas@southpole.se> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Ley Foon Tan <lftan@altera.com> Cc: Mark Salter <msalter@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Palmer Dabbelt <palmer@sifive.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Serge Semin <fancer.lancer@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-22Merge tag 'arm64-upstream' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 updates from Catalin Marinas: "Apart from some new arm64 features and clean-ups, this also contains the core mmu_gather changes for tracking the levels of the page table being cleared and a minor update to the generic compat_sys_sigaltstack() introducing COMPAT_SIGMINSKSZ. Summary: - Core mmu_gather changes which allow tracking the levels of page-table being cleared together with the arm64 low-level flushing routines - Support for the new ARMv8.5 PSTATE.SSBS bit which can be used to mitigate Spectre-v4 dynamically without trapping to EL3 firmware - Introduce COMPAT_SIGMINSTKSZ for use in compat_sys_sigaltstack - Optimise emulation of MRS instructions to ID_* registers on ARMv8.4 - Support for Common Not Private (CnP) translations allowing threads of the same CPU to share the TLB entries - Accelerated crc32 routines - Move swapper_pg_dir to the rodata section - Trap WFI instruction executed in user space - ARM erratum 1188874 workaround (arch_timer) - Miscellaneous fixes and clean-ups" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (78 commits) arm64: KVM: Guests can skip __install_bp_hardening_cb()s HYP work arm64: cpufeature: Trap CTR_EL0 access only where it is necessary arm64: cpufeature: Fix handling of CTR_EL0.IDC field arm64: cpufeature: ctr: Fix cpu capability check for late CPUs Documentation/arm64: HugeTLB page implementation arm64: mm: Use __pa_symbol() for set_swapper_pgd() arm64: Add silicon-errata.txt entry for ARM erratum 1188873 Revert "arm64: uaccess: implement unsafe accessors" arm64: mm: Drop the unused cpu parameter MAINTAINERS: fix bad sdei paths arm64: mm: Use #ifdef for the __PAGETABLE_P?D_FOLDED defines arm64: Fix typo in a comment in arch/arm64/mm/kasan_init.c arm64: xen: Use existing helper to check interrupt status arm64: Use daifflag_restore after bp_hardening arm64: daifflags: Use irqflags functions for daifflags arm64: arch_timer: avoid unused function warning arm64: Trap WFI executed in userspace arm64: docs: Document SSBS HWCAP arm64: docs: Fix typos in ELF hwcaps arm64/kprobes: remove an extra semicolon in arch_prepare_kprobe ...
2018-09-07mm/memory: Move mmu_gather and TLB invalidation code into its own filePeter Zijlstra
In preparation for maintaining the mmu_gather code as its own entity, move the implementation out of memory.c and into its own file. Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-08-30vfs: implement readahead(2) using POSIX_FADV_WILLNEEDAmir Goldstein
The implementation of readahead(2) syscall is identical to that of fadvise64(POSIX_FADV_WILLNEED) with a few exceptions: 1. readahead(2) returns -EINVAL for !mapping->a_ops and fadvise64() ignores the request and returns 0. 2. fadvise64() checks for integer overflow corner case 3. fadvise64() calls the optional filesystem fadvise() file operation Unite the two implementations by calling vfs_fadvise() from readahead(2) syscall. Check the !mapping->a_ops in readahead(2) syscall to preserve documented syscall ABI behaviour. Suggested-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: d1d04ef8572b ("ovl: stack file ops") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-06-07mm: restructure memfd codeMike Kravetz
With the addition of memfd hugetlbfs support, we now have the situation where memfd depends on TMPFS -or- HUGETLBFS. Previously, memfd was only supported on tmpfs, so it made sense that the code resided in shmem.c. In the current code, memfd is only functional if TMPFS is defined. If HUGETLFS is defined and TMPFS is not defined, then memfd functionality will not be available for hugetlbfs. This does not cause BUGs, just a lack of potentially desired functionality. Code is restructured in the following way: - include/linux/memfd.h is a new file containing memfd specific definitions previously contained in shmem_fs.h. - mm/memfd.c is a new file containing memfd specific code previously contained in shmem.c. - memfd specific code is removed from shmem_fs.h and shmem.c. - A new config option MEMFD_CREATE is added that is defined if TMPFS or HUGETLBFS is defined. No functional changes are made to the code: restructuring only. Link: http://lkml.kernel.org/r/20180415182119.4517-4-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Herrmann <dh.herrmann@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Marc-Andr Lureau <marcandre.lureau@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-05mm/swap_slots.c: use conditional compilationRandy Dunlap
For mm/swap_slots.c, use the traditional Linux method of conditional compilation and linking instead of always compiling it by using #ifdef CONFIG_SWAP and #endif for the entire source file (excluding header files). Link: http://lkml.kernel.org/r/c2a47015-0b5a-d0d9-8bc7-9984c049df20@infradead.org Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Tim Chen <tim.c.chen@linux.intel.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-17mm: add infrastructure for get_user_pages_fast() benchmarkingKirill A. Shutemov
Performance of get_user_pages_fast() is critical for some workloads, but it's tricky to test it directly. This patch provides /sys/kernel/debug/gup_benchmark that helps with testing performance of it. See tools/testing/selftests/vm/gup_benchmark.c for userspace counterpart. Link: http://lkml.kernel.org/r/20170908215603.9189-2-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thorsten Leemhuis <regressions@leemhuis.info> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Huang Ying <ying.huang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15kmemcheck: rip it outLevin, Alexander (Sasha Levin)
Fix up makefiles, remove references, and git rm kmemcheck. Link: http://lkml.kernel.org/r/20171007030159.22241-4-alexander.levin@verizon.com Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Vegard Nossum <vegardno@ifi.uio.no> Cc: Pekka Enberg <penberg@kernel.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Alexander Potapenko <glider@google.com> Cc: Tim Hansen <devtimhansen@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-09-08mm/hmm: avoid bloating arch that do not make use of HMMJérôme Glisse
This moves all new code including new page migration helper behind kernel Kconfig option so that there is no codee bloat for arch or user that do not want to use HMM or any of its associated features. arm allyesconfig (without all the patchset, then with and this patch): text data bss dec hex filename 83721896 46511131 27582964 157815991 96814b7 ../without/vmlinux 83722364 46511131 27582964 157816459 968168b vmlinux [jglisse@redhat.com: struct hmm is only use by HMM mirror functionality] Link: http://lkml.kernel.org/r/20170825213133.27286-1-jglisse@redhat.com [sfr@canb.auug.org.au: fix build (arm multi_v7_defconfig)] Link: http://lkml.kernel.org/r/20170828181849.323ab81b@canb.auug.org.au Link: http://lkml.kernel.org/r/20170818032858.7447-1-jglisse@redhat.com Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-08mm/hmm: heterogeneous memory management (HMM for short)Jérôme Glisse
HMM provides 3 separate types of functionality: - Mirroring: synchronize CPU page table and device page table - Device memory: allocating struct page for device memory - Migration: migrating regular memory to device memory This patch introduces some common helpers and definitions to all of those 3 functionality. Link: http://lkml.kernel.org/r/20170817000548.32038-3-jglisse@redhat.com Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Signed-off-by: Evgeny Baskakov <ebaskakov@nvidia.com> Signed-off-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Mark Hairgrove <mhairgrove@nvidia.com> Signed-off-by: Sherry Cheung <SCheung@nvidia.com> Signed-off-by: Subhash Gutti <sgutti@nvidia.com> Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Nellans <dnellans@nvidia.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Bob Liu <liubo95@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-20percpu: expose statistics about percpu memory via debugfsDennis Zhou
There is limited visibility into the use of percpu memory leaving us unable to reason about correctness of parameters and overall use of percpu memory. These counters and statistics aim to help understand basic statistics about percpu memory such as number of allocations over the lifetime, allocation sizes, and fragmentation. New Config: PERCPU_STATS Signed-off-by: Dennis Zhou <dennisz@fb.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2017-02-27mm: add arch-independent testcases for RODATAJinbum Park
This patch makes arch-independent testcases for RODATA. Both x86 and x86_64 already have testcases for RODATA, But they are arch-specific because using inline assembly directly. And cacheflush.h is not a suitable location for rodata-test related things. Since they were in cacheflush.h, If someone change the state of CONFIG_DEBUG_RODATA_TEST, It cause overhead of kernel build. To solve the above issues, write arch-independent testcases and move it to shared location. [jinb.park7@gmail.com: fix config dependency] Link: http://lkml.kernel.org/r/20170209131625.GA16954@pjb1027-Latitude-E5410 Link: http://lkml.kernel.org/r/20170129105436.GA9303@pjb1027-Latitude-E5410 Signed-off-by: Jinbum Park <jinb.park7@gmail.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Laura Abbott <labbott@redhat.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Valentin Rothberg <valentinrothberg@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24mm: introduce page_vma_mapped_walk()Kirill A. Shutemov
Introduce a new interface to check if a page is mapped into a vma. It aims to address shortcomings of page_check_address{,_transhuge}. Existing interface is not able to handle PTE-mapped THPs: it only finds the first PTE. The rest lefted unnoticed. page_vma_mapped_walk() iterates over all possible mapping of the page in the vma. Link: http://lkml.kernel.org/r/20170129173858.45174-3-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-22mm/swap: add cache for swap slots allocationTim Chen
We add per cpu caches for swap slots that can be allocated and freed quickly without the need to touch the swap info lock. Two separate caches are maintained for swap slots allocated and swap slots returned. This is to allow the swap slots to be returned to the global pool in a batch so they will have a chance to be coaelesced with other slots in a cluster. We do not reuse the slots that are returned right away, as it may increase fragmentation of the slots. The swap allocation cache is protected by a mutex as we may sleep when searching for empty slots in cache. The swap free cache is protected by a spin lock as we cannot sleep in the free path. We refill the swap slots cache when we run out of slots, and we disable the swap slots cache and drain the slots if the global number of slots fall below a low watermark threshold. We re-enable the cache agian when the slots available are above a high watermark. [ying.huang@intel.com: use raw_cpu_ptr over this_cpu_ptr for swap slots access] [tim.c.chen@linux.intel.com: add comments on locks in swap_slots.h] Link: http://lkml.kernel.org/r/20170118180327.GA24225@linux.intel.com Link: http://lkml.kernel.org/r/35de301a4eaa8daa2977de6e987f2c154385eb66.1484082593.git.tim.c.chen@linux.intel.com Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Michal Hocko <mhocko@suse.com> Cc: Aaron Lu <aaron.lu@intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> escreveu: Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Shaohua Li <shli@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-12Disable the __builtin_return_address() warning globally after allLinus Torvalds
This affectively reverts commit 377ccbb48373 ("Makefile: Mute warning for __builtin_return_address(>0) for tracing only") because it turns out that it really isn't tracing only - it's all over the tree. We already also had the warning disabled separately for mm/usercopy.c (which this commit also removes), and it turns out that we will also want to disable it for get_lock_parent_ip(), that is used for at least TRACE_IRQFLAGS. Which (when enabled) ends up being all over the tree. Steven Rostedt had a patch that tried to limit it to just the config options that actually triggered this, but quite frankly, the extra complexity and abstraction just isn't worth it. We have never actually had a case where the warning is actually useful, so let's just disable it globally and not worry about it. Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Anvin <hpa@zytor.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-08Merge tag 'usercopy-v4.8' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull usercopy protection from Kees Cook: "Tbhis implements HARDENED_USERCOPY verification of copy_to_user and copy_from_user bounds checking for most architectures on SLAB and SLUB" * tag 'usercopy-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: mm: SLUB hardened usercopy support mm: SLAB hardened usercopy support s390/uaccess: Enable hardened usercopy sparc/uaccess: Enable hardened usercopy powerpc/uaccess: Enable hardened usercopy ia64/uaccess: Enable hardened usercopy arm64/uaccess: Enable hardened usercopy ARM: uaccess: Enable hardened usercopy x86/uaccess: Enable hardened usercopy mm: Hardened usercopy mm: Implement stack frame object validation mm: Add is_migrate_cma_page
2016-07-26thp: extract khugepaged from mm/huge_memory.cKirill A. Shutemov
khugepaged implementation grew to the point when it deserve separate file in source. Let's move it to mm/khugepaged.c. Link: http://lkml.kernel.org/r/1466021202-61880-32-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-26mm: Hardened usercopyKees Cook
This is the start of porting PAX_USERCOPY into the mainline kernel. This is the first set of features, controlled by CONFIG_HARDENED_USERCOPY. The work is based on code by PaX Team and Brad Spengler, and an earlier port from Casey Schaufler. Additional non-slab page tests are from Rik van Riel. This patch contains the logic for validating several conditions when performing copy_to_user() and copy_from_user() on the kernel object being copied to/from: - address range doesn't wrap around - address range isn't NULL or zero-allocated (with a non-zero copy size) - if on the slab allocator: - object size must be less than or equal to copy size (when check is implemented in the allocator, which appear in subsequent patches) - otherwise, object must not span page allocations (excepting Reserved and CMA ranges) - if on the stack - object must not extend before/after the current process stack - object must be contained by a valid stack frame (when there is arch/build support for identifying stack frames) - object must not overlap with kernel text Signed-off-by: Kees Cook <keescook@chromium.org> Tested-by: Valdis Kletnieks <valdis.kletnieks@vt.edu> Tested-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-20z3fold: the 3-fold allocator for compressed pagesVitaly Wool
This patch introduces z3fold, a special purpose allocator for storing compressed pages. It is designed to store up to three compressed pages per physical page. It is a ZBUD derivative which allows for higher compression ratio keeping the simplicity and determinism of its predecessor. This patch comes as a follow-up to the discussions at the Embedded Linux Conference in San-Diego related to the talk [1]. The outcome of these discussions was that it would be good to have a compressed page allocator as stable and deterministic as zbud with with higher compression ratio. To keep the determinism and simplicity, z3fold, just like zbud, always stores an integral number of compressed pages per page, but it can store up to 3 pages unlike zbud which can store at most 2. Therefore the compression ratio goes to around 2.6x while zbud's one is around 1.7x. The patch is based on the latest linux.git tree. This version has been updated after testing on various simulators (e.g. ARM Versatile Express, MIPS Malta, x86_64/Haswell) and basing on comments from Dan Streetman [3]. [1] https://openiotelc2016.sched.org/event/6DAC/swapping-and-embedded-compression-relieves-the-pressure-vitaly-wool-softprise-consulting-ou [2] https://lkml.org/lkml/2016/4/21/799 [3] https://lkml.org/lkml/2016/5/4/852 Link: http://lkml.kernel.org/r/20160509151753.ec3f9fda3c9898d31ff52a32@gmail.com Signed-off-by: Vitaly Wool <vitalywool@gmail.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-25mm, kasan: SLAB supportAlexander Potapenko
Add KASAN hooks to SLAB allocator. This patch is based on the "mm: kasan: unified support for SLUB and SLAB allocators" patch originally prepared by Dmitry Chernenkov. Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Andrey Konovalov <adech.fo@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Konstantin Serebryany <kcc@google.com> Cc: Dmitry Chernenkov <dmitryc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22kernel: add kcov code coverageDmitry Vyukov
kcov provides code coverage collection for coverage-guided fuzzing (randomized testing). Coverage-guided fuzzing is a testing technique that uses coverage feedback to determine new interesting inputs to a system. A notable user-space example is AFL (http://lcamtuf.coredump.cx/afl/). However, this technique is not widely used for kernel testing due to missing compiler and kernel support. kcov does not aim to collect as much coverage as possible. It aims to collect more or less stable coverage that is function of syscall inputs. To achieve this goal it does not collect coverage in soft/hard interrupts and instrumentation of some inherently non-deterministic or non-interesting parts of kernel is disbled (e.g. scheduler, locking). Currently there is a single coverage collection mode (tracing), but the API anticipates additional collection modes. Initially I also implemented a second mode which exposes coverage in a fixed-size hash table of counters (what Quentin used in his original patch). I've dropped the second mode for simplicity. This patch adds the necessary support on kernel side. The complimentary compiler support was added in gcc revision 231296. We've used this support to build syzkaller system call fuzzer, which has found 90 kernel bugs in just 2 months: https://github.com/google/syzkaller/wiki/Found-Bugs We've also found 30+ bugs in our internal systems with syzkaller. Another (yet unexplored) direction where kcov coverage would greatly help is more traditional "blob mutation". For example, mounting a random blob as a filesystem, or receiving a random blob over wire. Why not gcov. Typical fuzzing loop looks as follows: (1) reset coverage, (2) execute a bit of code, (3) collect coverage, repeat. A typical coverage can be just a dozen of basic blocks (e.g. an invalid input). In such context gcov becomes prohibitively expensive as reset/collect coverage steps depend on total number of basic blocks/edges in program (in case of kernel it is about 2M). Cost of kcov depends only on number of executed basic blocks/edges. On top of that, kernel requires per-thread coverage because there are always background threads and unrelated processes that also produce coverage. With inlined gcov instrumentation per-thread coverage is not possible. kcov exposes kernel PCs and control flow to user-space which is insecure. But debugfs should not be mapped as user accessible. Based on a patch by Quentin Casasnovas. [akpm@linux-foundation.org: make task_struct.kcov_mode have type `enum kcov_mode'] [akpm@linux-foundation.org: unbreak allmodconfig] [akpm@linux-foundation.org: follow x86 Makefile layout standards] Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: syzkaller <syzkaller@googlegroups.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Tavis Ormandy <taviso@google.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Kostya Serebryany <kcc@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Kees Cook <keescook@google.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: David Drysdale <drysdale@google.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-17mm/page_ref: add tracepoint to track down page reference manipulationJoonsoo Kim
CMA allocation should be guaranteed to succeed by definition, but, unfortunately, it would be failed sometimes. It is hard to track down the problem, because it is related to page reference manipulation and we don't have any facility to analyze it. This patch adds tracepoints to track down page reference manipulation. With it, we can find exact reason of failure and can fix the problem. Following is an example of tracepoint output. (note: this example is stale version that printing flags as the number. Recent version will print it as human readable string.) <...>-9018 [004] 92.678375: page_ref_set: pfn=0x17ac9 flags=0x0 count=1 mapcount=0 mapping=(nil) mt=4 val=1 <...>-9018 [004] 92.678378: kernel_stack: => get_page_from_freelist (ffffffff81176659) => __alloc_pages_nodemask (ffffffff81176d22) => alloc_pages_vma (ffffffff811bf675) => handle_mm_fault (ffffffff8119e693) => __do_page_fault (ffffffff810631ea) => trace_do_page_fault (ffffffff81063543) => do_async_page_fault (ffffffff8105c40a) => async_page_fault (ffffffff817581d8) [snip] <...>-9018 [004] 92.678379: page_ref_mod: pfn=0x17ac9 flags=0x40048 count=2 mapcount=1 mapping=0xffff880015a78dc1 mt=4 val=1 [snip] ... ... <...>-9131 [001] 93.174468: test_pages_isolated: start_pfn=0x17800 end_pfn=0x17c00 fin_pfn=0x17ac9 ret=fail [snip] <...>-9018 [004] 93.174843: page_ref_mod_and_test: pfn=0x17ac9 flags=0x40068 count=0 mapcount=0 mapping=0xffff880015a78dc1 mt=4 val=-1 ret=1 => release_pages (ffffffff8117c9e4) => free_pages_and_swap_cache (ffffffff811b0697) => tlb_flush_mmu_free (ffffffff81199616) => tlb_finish_mmu (ffffffff8119a62c) => exit_mmap (ffffffff811a53f7) => mmput (ffffffff81073f47) => do_exit (ffffffff810794e9) => do_group_exit (ffffffff81079def) => SyS_exit_group (ffffffff81079e74) => entry_SYSCALL_64_fastpath (ffffffff817560b6) This output shows that problem comes from exit path. In exit path, to improve performance, pages are not freed immediately. They are gathered and processed by batch. During this process, migration cannot be possible and CMA allocation is failed. This problem is hard to find without this page reference tracepoint facility. Enabling this feature bloat kernel text 30 KB in my configuration. text data bss dec hex filename 12127327 2243616 1507328 15878271 f2487f vmlinux_disabled 12157208 2258880 1507328 15923416 f2f8d8 vmlinux_enabled Note that, due to header file dependency problem between mm.h and tracepoint.h, this feature has to open code the static key functions for tracepoints. Proposed by Steven Rostedt in following link. https://lkml.org/lkml/2015/12/9/699 [arnd@arndb.de: crypto/async_pq: use __free_page() instead of put_page()] [iamjoonsoo.kim@lge.com: fix build failure for xtensa] [akpm@linux-foundation.org: tweak Kconfig text, per Vlastimil] Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Michal Nazarewicz <mina86@mina86.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Minchan Kim <minchan@kernel.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-15mm/page_poison.c: enable PAGE_POISONING as a separate optionLaura Abbott
Page poisoning is currently set up as a feature if architectures don't have architecture debug page_alloc to allow unmapping of pages. It has uses apart from that though. Clearing of the pages on free provides an increase in security as it helps to limit the risk of information leaks. Allow page poisoning to be enabled as a separate option independent of kernel_map pages since the two features do separate work. Because of how hiberanation is implemented, the checks on alloc cannot occur if hibernation is enabled. The runtime alloc checks can also be enabled with an option when !HIBERNATION. Credit to Grsecurity/PaX team for inspiring this work Signed-off-by: Laura Abbott <labbott@fedoraproject.org> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@suse.com> Cc: Kees Cook <keescook@chromium.org> Cc: Mathias Krause <minipli@googlemail.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Jianyu Zhan <nasa4836@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11Merge tag 'media/v4.3-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media Pull media updates from Mauro Carvalho Chehab: "A series of patches that move part of the code used to allocate memory from the media subsystem to the mm subsystem" [ The mm parts have been acked by VM people, and the series was apparently in -mm for a while - Linus ] * tag 'media/v4.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: [media] drm/exynos: Convert g2d_userptr_get_dma_addr() to use get_vaddr_frames() [media] media: vb2: Remove unused functions [media] media: vb2: Convert vb2_dc_get_userptr() to use frame vector [media] media: vb2: Convert vb2_vmalloc_get_userptr() to use frame vector [media] media: vb2: Convert vb2_dma_sg_get_userptr() to use frame vector [media] vb2: Provide helpers for mapping virtual addresses [media] media: omap_vout: Convert omap_vout_uservirt_to_phys() to use get_vaddr_pfns() [media] mm: Provide new get_vaddr_frames() helper [media] vb2: Push mmap_sem down to memops
2015-09-10mm: introduce idle page trackingVladimir Davydov
Knowing the portion of memory that is not used by a certain application or memory cgroup (idle memory) can be useful for partitioning the system efficiently, e.g. by setting memory cgroup limits appropriately. Currently, the only means to estimate the amount of idle memory provided by the kernel is /proc/PID/{clear_refs,smaps}: the user can clear the access bit for all pages mapped to a particular process by writing 1 to clear_refs, wait for some time, and then count smaps:Referenced. However, this method has two serious shortcomings: - it does not count unmapped file pages - it affects the reclaimer logic To overcome these drawbacks, this patch introduces two new page flags, Idle and Young, and a new sysfs file, /sys/kernel/mm/page_idle/bitmap. A page's Idle flag can only be set from userspace by setting bit in /sys/kernel/mm/page_idle/bitmap at the offset corresponding to the page, and it is cleared whenever the page is accessed either through page tables (it is cleared in page_referenced() in this case) or using the read(2) system call (mark_page_accessed()). Thus by setting the Idle flag for pages of a particular workload, which can be found e.g. by reading /proc/PID/pagemap, waiting for some time to let the workload access its working set, and then reading the bitmap file, one can estimate the amount of pages that are not used by the workload. The Young page flag is used to avoid interference with the memory reclaimer. A page's Young flag is set whenever the Access bit of a page table entry pointing to the page is cleared by writing to the bitmap file. If page_referenced() is called on a Young page, it will add 1 to its return value, therefore concealing the fact that the Access bit was cleared. Note, since there is no room for extra page flags on 32 bit, this feature uses extended page flags when compiled on 32 bit. [akpm@linux-foundation.org: fix build] [akpm@linux-foundation.org: kpageidle requires an MMU] [akpm@linux-foundation.org: decouple from page-flags rework] Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Reviewed-by: Andres Lagar-Cavilla <andreslc@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Greg Thelen <gthelen@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>