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2022-11-30drm/amdgpu: temporarily disable broken Clang builds due to blown stack-frameLee Jones
Patch series "Fix a bunch of allmodconfig errors", v2. Since b339ec9c229aa ("kbuild: Only default to -Werror if COMPILE_TEST") WERROR now defaults to COMPILE_TEST meaning that it's enabled for allmodconfig builds. This leads to some interesting build failures when using Clang, each resolved in this set. With this set applied, I am able to obtain a successful allmodconfig Arm build. This patch (of 2): calculate_bandwidth() is presently broken on all !(X86_64 || SPARC64 || ARM64) architectures built with Clang (all released versions), whereby the stack frame gets blown up to well over 5k. This would cause an immediate kernel panic on most architectures. We'll revert this when the following bug report has been resolved: https://github.com/llvm/llvm-project/issues/41896. Link: https://lkml.kernel.org/r/20221125120750.3537134-1-lee@kernel.org Link: https://lkml.kernel.org/r/20221125120750.3537134-2-lee@kernel.org Signed-off-by: Lee Jones <lee@kernel.org> Suggested-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: "Christian König" <christian.koenig@amd.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: David Airlie <airlied@gmail.com> Cc: Harry Wentland <harry.wentland@amd.com> Cc: Lee Jones <lee@kernel.org> Cc: Leo Li <sunpeng.li@amd.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Maxime Ripard <mripard@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com> Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com> Cc: Thomas Zimmermann <tzimmermann@suse.de> Cc: Tom Rix <trix@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30mm/khugepaged: invoke MMU notifiers in shmem/file collapse pathsJann Horn
Any codepath that zaps page table entries must invoke MMU notifiers to ensure that secondary MMUs (like KVM) don't keep accessing pages which aren't mapped anymore. Secondary MMUs don't hold their own references to pages that are mirrored over, so failing to notify them can lead to page use-after-free. I'm marking this as addressing an issue introduced in commit f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages"), but most of the security impact of this only came in commit 27e1f8273113 ("khugepaged: enable collapse pmd for pte-mapped THP"), which actually omitted flushes for the removal of present PTEs, not just for the removal of empty page tables. Link: https://lkml.kernel.org/r/20221129154730.2274278-3-jannh@google.com Link: https://lkml.kernel.org/r/20221128180252.1684965-3-jannh@google.com Link: https://lkml.kernel.org/r/20221125213714.4115729-3-jannh@google.com Fixes: f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages") Signed-off-by: Jann Horn <jannh@google.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Peter Xu <peterx@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30mm/khugepaged: fix GUP-fast interaction by sending IPIJann Horn
Since commit 70cbc3cc78a99 ("mm: gup: fix the fast GUP race against THP collapse"), the lockless_pages_from_mm() fastpath rechecks the pmd_t to ensure that the page table was not removed by khugepaged in between. However, lockless_pages_from_mm() still requires that the page table is not concurrently freed. Fix it by sending IPIs (if the architecture uses semi-RCU-style page table freeing) before freeing/reusing page tables. Link: https://lkml.kernel.org/r/20221129154730.2274278-2-jannh@google.com Link: https://lkml.kernel.org/r/20221128180252.1684965-2-jannh@google.com Link: https://lkml.kernel.org/r/20221125213714.4115729-2-jannh@google.com Fixes: ba76149f47d8 ("thp: khugepaged") Signed-off-by: Jann Horn <jannh@google.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Peter Xu <peterx@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30mm/khugepaged: take the right locks for page table retractionJann Horn
pagetable walks on address ranges mapped by VMAs can be done under the mmap lock, the lock of an anon_vma attached to the VMA, or the lock of the VMA's address_space. Only one of these needs to be held, and it does not need to be held in exclusive mode. Under those circumstances, the rules for concurrent access to page table entries are: - Terminal page table entries (entries that don't point to another page table) can be arbitrarily changed under the page table lock, with the exception that they always need to be consistent for hardware page table walks and lockless_pages_from_mm(). This includes that they can be changed into non-terminal entries. - Non-terminal page table entries (which point to another page table) can not be modified; readers are allowed to READ_ONCE() an entry, verify that it is non-terminal, and then assume that its value will stay as-is. Retracting a page table involves modifying a non-terminal entry, so page-table-level locks are insufficient to protect against concurrent page table traversal; it requires taking all the higher-level locks under which it is possible to start a page walk in the relevant range in exclusive mode. The collapse_huge_page() path for anonymous THP already follows this rule, but the shmem/file THP path was getting it wrong, making it possible for concurrent rmap-based operations to cause corruption. Link: https://lkml.kernel.org/r/20221129154730.2274278-1-jannh@google.com Link: https://lkml.kernel.org/r/20221128180252.1684965-1-jannh@google.com Link: https://lkml.kernel.org/r/20221125213714.4115729-1-jannh@google.com Fixes: 27e1f8273113 ("khugepaged: enable collapse pmd for pte-mapped THP") Signed-off-by: Jann Horn <jannh@google.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Peter Xu <peterx@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30mm: migrate: fix THP's mapcount on isolationGavin Shan
The issue is reported when removing memory through virtio_mem device. The transparent huge page, experienced copy-on-write fault, is wrongly regarded as pinned. The transparent huge page is escaped from being isolated in isolate_migratepages_block(). The transparent huge page can't be migrated and the corresponding memory block can't be put into offline state. Fix it by replacing page_mapcount() with total_mapcount(). With this, the transparent huge page can be isolated and migrated, and the memory block can be put into offline state. Besides, The page's refcount is increased a bit earlier to avoid the page is released when the check is executed. Link: https://lkml.kernel.org/r/20221124095523.31061-1-gshan@redhat.com Fixes: 1da2f328fa64 ("mm,thp,compaction,cma: allow THP migration for CMA allocations") Signed-off-by: Gavin Shan <gshan@redhat.com> Reported-by: Zhenyu Zhang <zhenyzha@redhat.com> Tested-by: Zhenyu Zhang <zhenyzha@redhat.com> Suggested-by: David Hildenbrand <david@redhat.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: William Kucharski <william.kucharski@oracle.com> Cc: Zi Yan <ziy@nvidia.com> Cc: <stable@vger.kernel.org> [5.7+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30mm: introduce arch_has_hw_nonleaf_pmd_young()Juergen Gross
When running as a Xen PV guests commit eed9a328aa1a ("mm: x86: add CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG") can cause a protection violation in pmdp_test_and_clear_young(): BUG: unable to handle page fault for address: ffff8880083374d0 #PF: supervisor write access in kernel mode #PF: error_code(0x0003) - permissions violation PGD 3026067 P4D 3026067 PUD 3027067 PMD 7fee5067 PTE 8010000008337065 Oops: 0003 [#1] PREEMPT SMP NOPTI CPU: 7 PID: 158 Comm: kswapd0 Not tainted 6.1.0-rc5-20221118-doflr+ #1 RIP: e030:pmdp_test_and_clear_young+0x25/0x40 This happens because the Xen hypervisor can't emulate direct writes to page table entries other than PTEs. This can easily be fixed by introducing arch_has_hw_nonleaf_pmd_young() similar to arch_has_hw_pte_young() and test that instead of CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG. Link: https://lkml.kernel.org/r/20221123064510.16225-1-jgross@suse.com Fixes: eed9a328aa1a ("mm: x86: add CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG") Signed-off-by: Juergen Gross <jgross@suse.com> Reported-by: Sander Eikelenboom <linux@eikelenboom.it> Acked-by: Yu Zhao <yuzhao@google.com> Tested-by: Sander Eikelenboom <linux@eikelenboom.it> Acked-by: David Hildenbrand <david@redhat.com> [core changes] Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30mm: add dummy pmd_young() for architectures not having itJuergen Gross
In order to avoid #ifdeffery add a dummy pmd_young() implementation as a fallback. This is required for the later patch "mm: introduce arch_has_hw_nonleaf_pmd_young()". Link: https://lkml.kernel.org/r/fd3ac3cd-7349-6bbd-890a-71a9454ca0b3@suse.com Signed-off-by: Juergen Gross <jgross@suse.com> Acked-by: Yu Zhao <yuzhao@google.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Sander Eikelenboom <linux@eikelenboom.it> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30mm/damon/sysfs: fix wrong empty schemes assumption under online tuning in ↵SeongJae Park
damon_sysfs_set_schemes() Commit da87878010e5 ("mm/damon/sysfs: support online inputs update") made 'damon_sysfs_set_schemes()' to be called for running DAMON context, which could have schemes. In the case, DAMON sysfs interface is supposed to update, remove, or add schemes to reflect the sysfs files. However, the code is assuming the DAMON context wouldn't have schemes at all, and therefore creates and adds new schemes. As a result, the code doesn't work as intended for online schemes tuning and could have more than expected memory footprint. The schemes are all in the DAMON context, so it doesn't leak the memory, though. Remove the wrong asssumption (the DAMON context wouldn't have schemes) in 'damon_sysfs_set_schemes()' to fix the bug. Link: https://lkml.kernel.org/r/20221122194831.3472-1-sj@kernel.org Fixes: da87878010e5 ("mm/damon/sysfs: support online inputs update") Signed-off-by: SeongJae Park <sj@kernel.org> Cc: <stable@vger.kernel.org> [5.19+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30tools/vm/slabinfo-gnuplot: use "grep -E" instead of "egrep"Tiezhu Yang
The latest version of grep claims the egrep is now obsolete so the build now contains warnings that look like: egrep: warning: egrep is obsolescent; using grep -E fix this up by moving the related file to use "grep -E" instead. sed -i "s/egrep/grep -E/g" `grep egrep -rwl tools/vm` Here are the steps to install the latest grep: wget http://ftp.gnu.org/gnu/grep/grep-3.8.tar.gz tar xf grep-3.8.tar.gz cd grep-3.8 && ./configure && make sudo make install export PATH=/usr/local/bin:$PATH Link: https://lkml.kernel.org/r/1668825419-30584-1-git-send-email-yangtiezhu@loongson.cn Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30nilfs2: fix NULL pointer dereference in nilfs_palloc_commit_free_entry()ZhangPeng
Syzbot reported a null-ptr-deref bug: NILFS (loop0): segctord starting. Construction interval = 5 seconds, CP frequency < 30 seconds general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] CPU: 1 PID: 3603 Comm: segctord Not tainted 6.1.0-rc2-syzkaller-00105-gb229b6ca5abb #0 Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022 RIP: 0010:nilfs_palloc_commit_free_entry+0xe5/0x6b0 fs/nilfs2/alloc.c:608 Code: 00 00 00 00 fc ff df 80 3c 02 00 0f 85 cd 05 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 73 08 49 8d 7e 10 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 26 05 00 00 49 8b 46 10 be a6 00 00 00 48 c7 c7 RSP: 0018:ffffc90003dff830 EFLAGS: 00010212 RAX: dffffc0000000000 RBX: ffff88802594e218 RCX: 000000000000000d RDX: 0000000000000002 RSI: 0000000000002000 RDI: 0000000000000010 RBP: ffff888071880222 R08: 0000000000000005 R09: 000000000000003f R10: 000000000000000d R11: 0000000000000000 R12: ffff888071880158 R13: ffff88802594e220 R14: 0000000000000000 R15: 0000000000000004 FS: 0000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb1c08316a8 CR3: 0000000018560000 CR4: 0000000000350ee0 Call Trace: <TASK> nilfs_dat_commit_free fs/nilfs2/dat.c:114 [inline] nilfs_dat_commit_end+0x464/0x5f0 fs/nilfs2/dat.c:193 nilfs_dat_commit_update+0x26/0x40 fs/nilfs2/dat.c:236 nilfs_btree_commit_update_v+0x87/0x4a0 fs/nilfs2/btree.c:1940 nilfs_btree_commit_propagate_v fs/nilfs2/btree.c:2016 [inline] nilfs_btree_propagate_v fs/nilfs2/btree.c:2046 [inline] nilfs_btree_propagate+0xa00/0xd60 fs/nilfs2/btree.c:2088 nilfs_bmap_propagate+0x73/0x170 fs/nilfs2/bmap.c:337 nilfs_collect_file_data+0x45/0xd0 fs/nilfs2/segment.c:568 nilfs_segctor_apply_buffers+0x14a/0x470 fs/nilfs2/segment.c:1018 nilfs_segctor_scan_file+0x3f4/0x6f0 fs/nilfs2/segment.c:1067 nilfs_segctor_collect_blocks fs/nilfs2/segment.c:1197 [inline] nilfs_segctor_collect fs/nilfs2/segment.c:1503 [inline] nilfs_segctor_do_construct+0x12fc/0x6af0 fs/nilfs2/segment.c:2045 nilfs_segctor_construct+0x8e3/0xb30 fs/nilfs2/segment.c:2379 nilfs_segctor_thread_construct fs/nilfs2/segment.c:2487 [inline] nilfs_segctor_thread+0x3c3/0xf30 fs/nilfs2/segment.c:2570 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 </TASK> ... If DAT metadata file is corrupted on disk, there is a case where req->pr_desc_bh is NULL and blocknr is 0 at nilfs_dat_commit_end() during a b-tree operation that cascadingly updates ancestor nodes of the b-tree, because nilfs_dat_commit_alloc() for a lower level block can initialize the blocknr on the same DAT entry between nilfs_dat_prepare_end() and nilfs_dat_commit_end(). If this happens, nilfs_dat_commit_end() calls nilfs_dat_commit_free() without valid buffer heads in req->pr_desc_bh and req->pr_bitmap_bh, and causes the NULL pointer dereference above in nilfs_palloc_commit_free_entry() function, which leads to a crash. Fix this by adding a NULL check on req->pr_desc_bh and req->pr_bitmap_bh before nilfs_palloc_commit_free_entry() in nilfs_dat_commit_free(). This also calls nilfs_error() in that case to notify that there is a fatal flaw in the filesystem metadata and prevent further operations. Link: https://lkml.kernel.org/r/00000000000097c20205ebaea3d6@google.com Link: https://lkml.kernel.org/r/20221114040441.1649940-1-zhangpeng362@huawei.com Link: https://lkml.kernel.org/r/20221119120542.17204-1-konishi.ryusuke@gmail.com Signed-off-by: ZhangPeng <zhangpeng362@huawei.com> Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> Reported-by: syzbot+ebe05ee8e98f755f61d0@syzkaller.appspotmail.com Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30hugetlb: don't delete vma_lock in hugetlb MADV_DONTNEED processingMike Kravetz
madvise(MADV_DONTNEED) ends up calling zap_page_range() to clear page tables associated with the address range. For hugetlb vmas, zap_page_range will call __unmap_hugepage_range_final. However, __unmap_hugepage_range_final assumes the passed vma is about to be removed and deletes the vma_lock to prevent pmd sharing as the vma is on the way out. In the case of madvise(MADV_DONTNEED) the vma remains, but the missing vma_lock prevents pmd sharing and could potentially lead to issues with truncation/fault races. This issue was originally reported here [1] as a BUG triggered in page_try_dup_anon_rmap. Prior to the introduction of the hugetlb vma_lock, __unmap_hugepage_range_final cleared the VM_MAYSHARE flag to prevent pmd sharing. Subsequent faults on this vma were confused as VM_MAYSHARE indicates a sharable vma, but was not set so page_mapping was not set in new pages added to the page table. This resulted in pages that appeared anonymous in a VM_SHARED vma and triggered the BUG. Address issue by adding a new zap flag ZAP_FLAG_UNMAP to indicate an unmap call from unmap_vmas(). This is used to indicate the 'final' unmapping of a hugetlb vma. When called via MADV_DONTNEED, this flag is not set and the vm_lock is not deleted. [1] https://lore.kernel.org/lkml/CAO4mrfdLMXsao9RF4fUE8-Wfde8xmjsKrTNMNC9wjUb6JudD0g@mail.gmail.com/ Link: https://lkml.kernel.org/r/20221114235507.294320-3-mike.kravetz@oracle.com Fixes: 90e7e7f5ef3f ("mm: enable MADV_DONTNEED for hugetlb mappings") Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reported-by: Wei Chen <harperchen1110@gmail.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mina Almasry <almasrymina@google.com> Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Cc: Peter Xu <peterx@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30madvise: use zap_page_range_single for madvise dontneedMike Kravetz
This series addresses the issue first reported in [1], and fully described in patch 2. Patches 1 and 2 address the user visible issue and are tagged for stable backports. While exploring solutions to this issue, related problems with mmu notification calls were discovered. This is addressed in the patch "hugetlb: remove duplicate mmu notifications:". Since there are no user visible effects, this third is not tagged for stable backports. Previous discussions suggested further cleanup by removing the routine zap_page_range. This is possible because zap_page_range_single is now exported, and all callers of zap_page_range pass ranges entirely within a single vma. This work will be done in a later patch so as not to distract from this bug fix. [1] https://lore.kernel.org/lkml/CAO4mrfdLMXsao9RF4fUE8-Wfde8xmjsKrTNMNC9wjUb6JudD0g@mail.gmail.com/ This patch (of 2): Expose the routine zap_page_range_single to zap a range within a single vma. The madvise routine madvise_dontneed_single_vma can use this routine as it explicitly operates on a single vma. Also, update the mmu notification range in zap_page_range_single to take hugetlb pmd sharing into account. This is required as MADV_DONTNEED supports hugetlb vmas. Link: https://lkml.kernel.org/r/20221114235507.294320-1-mike.kravetz@oracle.com Link: https://lkml.kernel.org/r/20221114235507.294320-2-mike.kravetz@oracle.com Fixes: 90e7e7f5ef3f ("mm: enable MADV_DONTNEED for hugetlb mappings") Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reported-by: Wei Chen <harperchen1110@gmail.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mina Almasry <almasrymina@google.com> Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Cc: Peter Xu <peterx@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30mm: replace VM_WARN_ON to pr_warn if the node is offline with __GFP_THISNODEYang Shi
Syzbot reported the below splat: WARNING: CPU: 1 PID: 3646 at include/linux/gfp.h:221 __alloc_pages_node include/linux/gfp.h:221 [inline] WARNING: CPU: 1 PID: 3646 at include/linux/gfp.h:221 hpage_collapse_alloc_page mm/khugepaged.c:807 [inline] WARNING: CPU: 1 PID: 3646 at include/linux/gfp.h:221 alloc_charge_hpage+0x802/0xaa0 mm/khugepaged.c:963 Modules linked in: CPU: 1 PID: 3646 Comm: syz-executor210 Not tainted 6.1.0-rc1-syzkaller-00454-ga70385240892 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022 RIP: 0010:__alloc_pages_node include/linux/gfp.h:221 [inline] RIP: 0010:hpage_collapse_alloc_page mm/khugepaged.c:807 [inline] RIP: 0010:alloc_charge_hpage+0x802/0xaa0 mm/khugepaged.c:963 Code: e5 01 4c 89 ee e8 6e f9 ae ff 4d 85 ed 0f 84 28 fc ff ff e8 70 fc ae ff 48 8d 6b ff 4c 8d 63 07 e9 16 fc ff ff e8 5e fc ae ff <0f> 0b e9 96 fa ff ff 41 bc 1a 00 00 00 e9 86 fd ff ff e8 47 fc ae RSP: 0018:ffffc90003fdf7d8 EFLAGS: 00010293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff888077f457c0 RSI: ffffffff81cd8f42 RDI: 0000000000000001 RBP: ffff888079388c0c R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f6b48ccf700(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6b48a819f0 CR3: 00000000171e7000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> collapse_file+0x1ca/0x5780 mm/khugepaged.c:1715 hpage_collapse_scan_file+0xd6c/0x17a0 mm/khugepaged.c:2156 madvise_collapse+0x53a/0xb40 mm/khugepaged.c:2611 madvise_vma_behavior+0xd0a/0x1cc0 mm/madvise.c:1066 madvise_walk_vmas+0x1c7/0x2b0 mm/madvise.c:1240 do_madvise.part.0+0x24a/0x340 mm/madvise.c:1419 do_madvise mm/madvise.c:1432 [inline] __do_sys_madvise mm/madvise.c:1432 [inline] __se_sys_madvise mm/madvise.c:1430 [inline] __x64_sys_madvise+0x113/0x150 mm/madvise.c:1430 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f6b48a4eef9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f6b48ccf318 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 00007f6b48af0048 RCX: 00007f6b48a4eef9 RDX: 0000000000000019 RSI: 0000000000600003 RDI: 0000000020000000 RBP: 00007f6b48af0040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6b48aa53a4 R13: 00007f6b48bffcbf R14: 00007f6b48ccf400 R15: 0000000000022000 </TASK> It is because khugepaged allocates pages with __GFP_THISNODE, but the preferred node is bogus. The previous patch fixed the khugepaged code to avoid allocating page from non-existing node. But it is still racy against memory hotremove. There is no synchronization with the memory hotplug so it is possible that memory gets offline during a longer taking scanning. So this warning still seems not quite helpful because: * There is no guarantee the node is online for __GFP_THISNODE context for all the callsites. * Kernel just fails the allocation regardless the warning, and it looks all callsites handle the allocation failure gracefully. Although while the warning has helped to identify a buggy code, it is not safe in general and this warning could panic the system with panic-on-warn configuration which tends to be used surprisingly often. So replace VM_WARN_ON to pr_warn(). And the warning will be triggered if __GFP_NOWARN is set since the allocator would print out warning for such case if __GFP_NOWARN is not set. [shy828301@gmail.com: rename nid to this_node and gfp to warn_gfp] Link: https://lkml.kernel.org/r/20221123193014.153983-1-shy828301@gmail.com [akpm@linux-foundation.org: fix whitespace] [akpm@linux-foundation.org: print gfp_mask instead of warn_gfp, per Michel] Link: https://lkml.kernel.org/r/20221108184357.55614-3-shy828301@gmail.com Fixes: 7d8faaf15545 ("mm/madvise: introduce MADV_COLLAPSE sync hugepage collapse") Signed-off-by: Yang Shi <shy828301@gmail.com> Reported-by: <syzbot+0044b22d177870ee974f@syzkaller.appspotmail.com> Suggested-by: Michal Hocko <mhocko@suse.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Zach O'Keefe <zokeefe@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30Merge branches 'doc.2022.10.20a', 'fixes.2022.10.21a', 'lazy.2022.11.30a', ↵Paul E. McKenney
'srcunmisafe.2022.11.09a', 'torture.2022.10.18c' and 'torturescript.2022.10.20a' into HEAD doc.2022.10.20a: Documentation updates. fixes.2022.10.21a: Miscellaneous fixes. lazy.2022.11.30a: Lazy call_rcu() and NOCB updates. srcunmisafe.2022.11.09a: NMI-safe SRCU readers. torture.2022.10.18c: Torture-test updates. torturescript.2022.10.20a: Torture-test scripting updates.
2022-11-30net: devinet: Reduce refcount before grace periodEric Dumazet
Currently, the inetdev_destroy() function waits for an RCU grace period before decrementing the refcount and freeing memory. This causes a delay with a new RCU configuration that tries to save power, which results in the network interface disappearing later than expected. The resulting delay causes test failures on ChromeOS. Refactor the code such that the refcount is freed before the grace period and memory is freed after. With this a ChromeOS network test passes that does 'ip netns del' and polls for an interface disappearing, now passes. Reported-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Cc: David Ahern <dsahern@kernel.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Paolo Abeni <pabeni@redhat.com> Cc: <netdev@vger.kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-11-30net: Use call_rcu_hurry() for dst_release()Joel Fernandes (Google)
In a networking test on ChromeOS, kernels built with the new CONFIG_RCU_LAZY=y Kconfig option fail a networking test in the teardown phase. This failure may be reproduced as follows: ip netns del <name> The CONFIG_RCU_LAZY=y Kconfig option was introduced by earlier commits in this series for the benefit of certain battery-powered systems. This Kconfig option causes call_rcu() to delay its callbacks in order to batch them. This means that a given RCU grace period covers more callbacks, thus reducing the number of grace periods, in turn reducing the amount of energy consumed, which increases battery lifetime which can be a very good thing. This is not a subtle effect: In some important use cases, the battery lifetime is increased by more than 10%. This CONFIG_RCU_LAZY=y option is available only for CPUs that offload callbacks, for example, CPUs mentioned in the rcu_nocbs kernel boot parameter passed to kernels built with CONFIG_RCU_NOCB_CPU=y. Delaying callbacks is normally not a problem because most callbacks do nothing but free memory. If the system is short on memory, a shrinker will kick all currently queued lazy callbacks out of their laziness, thus freeing their memory in short order. Similarly, the rcu_barrier() function, which blocks until all currently queued callbacks are invoked, will also kick lazy callbacks, thus enabling rcu_barrier() to complete in a timely manner. However, there are some cases where laziness is not a good option. For example, synchronize_rcu() invokes call_rcu(), and blocks until the newly queued callback is invoked. It would not be a good for synchronize_rcu() to block for ten seconds, even on an idle system. Therefore, synchronize_rcu() invokes call_rcu_hurry() instead of call_rcu(). The arrival of a non-lazy call_rcu_hurry() callback on a given CPU kicks any lazy callbacks that might be already queued on that CPU. After all, if there is going to be a grace period, all callbacks might as well get full benefit from it. Yes, this could be done the other way around by creating a call_rcu_lazy(), but earlier experience with this approach and feedback at the 2022 Linux Plumbers Conference shifted the approach to call_rcu() being lazy with call_rcu_hurry() for the few places where laziness is inappropriate. Returning to the test failure, use of ftrace showed that this failure cause caused by the aadded delays due to this new lazy behavior of call_rcu() in kernels built with CONFIG_RCU_LAZY=y. Therefore, make dst_release() use call_rcu_hurry() in order to revert to the old test-failure-free behavior. [ paulmck: Apply s/call_rcu_flush/call_rcu_hurry/ feedback from Tejun Heo. ] Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Cc: David Ahern <dsahern@kernel.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Paolo Abeni <pabeni@redhat.com> Cc: <netdev@vger.kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-11-30workqueue: Make queue_rcu_work() use call_rcu_hurry()Uladzislau Rezki
Earlier commits in this series allow battery-powered systems to build their kernels with the default-disabled CONFIG_RCU_LAZY=y Kconfig option. This Kconfig option causes call_rcu() to delay its callbacks in order to batch them. This means that a given RCU grace period covers more callbacks, thus reducing the number of grace periods, in turn reducing the amount of energy consumed, which increases battery lifetime which can be a very good thing. This is not a subtle effect: In some important use cases, the battery lifetime is increased by more than 10%. This CONFIG_RCU_LAZY=y option is available only for CPUs that offload callbacks, for example, CPUs mentioned in the rcu_nocbs kernel boot parameter passed to kernels built with CONFIG_RCU_NOCB_CPU=y. Delaying callbacks is normally not a problem because most callbacks do nothing but free memory. If the system is short on memory, a shrinker will kick all currently queued lazy callbacks out of their laziness, thus freeing their memory in short order. Similarly, the rcu_barrier() function, which blocks until all currently queued callbacks are invoked, will also kick lazy callbacks, thus enabling rcu_barrier() to complete in a timely manner. However, there are some cases where laziness is not a good option. For example, synchronize_rcu() invokes call_rcu(), and blocks until the newly queued callback is invoked. It would not be a good for synchronize_rcu() to block for ten seconds, even on an idle system. Therefore, synchronize_rcu() invokes call_rcu_hurry() instead of call_rcu(). The arrival of a non-lazy call_rcu_hurry() callback on a given CPU kicks any lazy callbacks that might be already queued on that CPU. After all, if there is going to be a grace period, all callbacks might as well get full benefit from it. Yes, this could be done the other way around by creating a call_rcu_lazy(), but earlier experience with this approach and feedback at the 2022 Linux Plumbers Conference shifted the approach to call_rcu() being lazy with call_rcu_hurry() for the few places where laziness is inappropriate. And another call_rcu() instance that cannot be lazy is the one in queue_rcu_work(), given that callers to queue_rcu_work() are not necessarily OK with long delays. Therefore, make queue_rcu_work() use call_rcu_hurry() in order to revert to the old behavior. [ paulmck: Apply s/call_rcu_flush/call_rcu_hurry/ feedback from Tejun Heo. ] Signed-off-by: Uladzislau Rezki <urezki@gmail.com> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Acked-by: Tejun Heo <tj@kernel.org> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-11-30percpu-refcount: Use call_rcu_hurry() for atomic switchJoel Fernandes (Google)
Earlier commits in this series allow battery-powered systems to build their kernels with the default-disabled CONFIG_RCU_LAZY=y Kconfig option. This Kconfig option causes call_rcu() to delay its callbacks in order to batch callbacks. This means that a given RCU grace period covers more callbacks, thus reducing the number of grace periods, in turn reducing the amount of energy consumed, which increases battery lifetime which can be a very good thing. This is not a subtle effect: In some important use cases, the battery lifetime is increased by more than 10%. This CONFIG_RCU_LAZY=y option is available only for CPUs that offload callbacks, for example, CPUs mentioned in the rcu_nocbs kernel boot parameter passed to kernels built with CONFIG_RCU_NOCB_CPU=y. Delaying callbacks is normally not a problem because most callbacks do nothing but free memory. If the system is short on memory, a shrinker will kick all currently queued lazy callbacks out of their laziness, thus freeing their memory in short order. Similarly, the rcu_barrier() function, which blocks until all currently queued callbacks are invoked, will also kick lazy callbacks, thus enabling rcu_barrier() to complete in a timely manner. However, there are some cases where laziness is not a good option. For example, synchronize_rcu() invokes call_rcu(), and blocks until the newly queued callback is invoked. It would not be a good for synchronize_rcu() to block for ten seconds, even on an idle system. Therefore, synchronize_rcu() invokes call_rcu_hurry() instead of call_rcu(). The arrival of a non-lazy call_rcu_hurry() callback on a given CPU kicks any lazy callbacks that might be already queued on that CPU. After all, if there is going to be a grace period, all callbacks might as well get full benefit from it. Yes, this could be done the other way around by creating a call_rcu_lazy(), but earlier experience with this approach and feedback at the 2022 Linux Plumbers Conference shifted the approach to call_rcu() being lazy with call_rcu_hurry() for the few places where laziness is inappropriate. And another call_rcu() instance that cannot be lazy is the one on the percpu refcounter's "per-CPU to atomic switch" code path, which uses RCU when switching to atomic mode. The enqueued callback wakes up waiters waiting in the percpu_ref_switch_waitq. Allowing this callback to be lazy would result in unacceptable slowdowns for users of per-CPU refcounts, such as blk_pre_runtime_suspend(). Therefore, make __percpu_ref_switch_to_atomic() use call_rcu_hurry() in order to revert to the old behavior. [ paulmck: Apply s/call_rcu_flush/call_rcu_hurry/ feedback from Tejun Heo. ] Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Dennis Zhou <dennis@kernel.org> Cc: Christoph Lameter <cl@linux.com> Cc: <linux-mm@kvack.org>
2022-11-30igb: Allocate MSI-X vector when testingAkihiko Odaki
Without this change, the interrupt test fail with MSI-X environment: $ sudo ethtool -t enp0s2 offline [ 43.921783] igb 0000:00:02.0: offline testing starting [ 44.855824] igb 0000:00:02.0 enp0s2: igb: enp0s2 NIC Link is Down [ 44.961249] igb 0000:00:02.0 enp0s2: igb: enp0s2 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX/TX [ 51.272202] igb 0000:00:02.0: testing shared interrupt [ 56.996975] igb 0000:00:02.0 enp0s2: igb: enp0s2 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX/TX The test result is FAIL The test extra info: Register test (offline) 0 Eeprom test (offline) 0 Interrupt test (offline) 4 Loopback test (offline) 0 Link test (on/offline) 0 Here, "4" means an expected interrupt was not delivered. To fix this, route IRQs correctly to the first MSI-X vector by setting IVAR_MISC. Also, set bit 0 of EIMS so that the vector will not be masked. The interrupt test now runs properly with this change: $ sudo ethtool -t enp0s2 offline [ 42.762985] igb 0000:00:02.0: offline testing starting [ 50.141967] igb 0000:00:02.0: testing shared interrupt [ 56.163957] igb 0000:00:02.0 enp0s2: igb: enp0s2 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX/TX The test result is PASS The test extra info: Register test (offline) 0 Eeprom test (offline) 0 Interrupt test (offline) 0 Loopback test (offline) 0 Link test (on/offline) 0 Fixes: 4eefa8f01314 ("igb: add single vector msi-x testing to interrupt test") Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com> Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Tested-by: Gurucharan G <gurucharanx.g@intel.com> (A Contingent worker at Intel) Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
2022-11-30e1000e: Fix TX dispatch conditionAkihiko Odaki
e1000_xmit_frame is expected to stop the queue and dispatch frames to hardware if there is not sufficient space for the next frame in the buffer, but sometimes it failed to do so because the estimated maximum size of frame was wrong. As the consequence, the later invocation of e1000_xmit_frame failed with NETDEV_TX_BUSY, and the frame in the buffer remained forever, resulting in a watchdog failure. This change fixes the estimated size by making it match with the condition for NETDEV_TX_BUSY. Apparently, the old estimation failed to account for the following lines which determines the space requirement for not causing NETDEV_TX_BUSY: ``` /* reserve a descriptor for the offload context */ if ((mss) || (skb->ip_summed == CHECKSUM_PARTIAL)) count++; count++; count += DIV_ROUND_UP(len, adapter->tx_fifo_limit); ``` This issue was found when running http-stress02 test included in Linux Test Project 20220930 on QEMU with the following commandline: ``` qemu-system-x86_64 -M q35,accel=kvm -m 8G -smp 8 -drive if=virtio,format=raw,file=root.img,file.locking=on -device e1000e,netdev=netdev -netdev tap,script=ifup,downscript=no,id=netdev ``` Fixes: bc7f75fa9788 ("[E1000E]: New pci-express e1000 driver (currently for ICH9 devices only)") Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com> Tested-by: Gurucharan G <gurucharanx.g@intel.com> (A Contingent worker at Intel) Tested-by: Naama Meir <naamax.meir@linux.intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
2022-11-30afs: Fix server->active leak in afs_put_serverMarc Dionne
The atomic_read was accidentally replaced with atomic_inc_return, which prevents the server from getting cleaned up and causes rmmod to hang with a warning: Can't purge s=00000001 Fixes: 2757a4dc1849 ("afs: Fix access after dec in put functions") Signed-off-by: Marc Dionne <marc.dionne@auristor.com> Signed-off-by: David Howells <dhowells@redhat.com> Link: https://lore.kernel.org/r/20221130174053.2665818-1-marc.dionne@auristor.com/ Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-11-30drm/i915: fix TLB invalidation for Gen12 video and compute enginesAndrzej Hajda
In case of Gen12 video and compute engines, TLB_INV registers are masked - to modify one bit, corresponding bit in upper half of the register must be enabled, otherwise nothing happens. CVE: CVE-2022-4139 Suggested-by: Chris Wilson <chris.p.wilson@intel.com> Signed-off-by: Andrzej Hajda <andrzej.hajda@intel.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Fixes: 7938d61591d3 ("drm/i915: Flush TLBs before releasing backing store") Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-11-30Merge tag 'asoc-fix-v6.1-rc7' of ↵Takashi Iwai
https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus ASoC: Fixes for v6.1 Some more fixes for v6.1, some of these are very old and were originally intended to get sent for v5.18 but got lost in the shuffle when there was an issue with Linus not liking my branching strategy and I rebuilt bits of my workflow. The ops changes have been validated by people looking at real hardware and are how things getting dropped got noticed.
2022-11-30gpio: amd8111: Fix PCI device reference count leakXiongfeng Wang
for_each_pci_dev() is implemented by pci_get_device(). The comment of pci_get_device() says that it will increase the reference count for the returned pci_dev and also decrease the reference count for the input pci_dev @from if it is not NULL. If we break for_each_pci_dev() loop with pdev not NULL, we need to call pci_dev_put() to decrease the reference count. Add the missing pci_dev_put() after the 'out' label. Since pci_dev_put() can handle NULL input parameter, there is no problem for the 'Device not found' branch. For the normal path, add pci_dev_put() in amd_gpio_exit(). Fixes: f942a7de047d ("gpio: add a driver for GPIO pins found on AMD-8111 south bridge chips") Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
2022-11-30KVM: x86: fix uninitialized variable use on KVM_REQ_TRIPLE_FAULTPaolo Bonzini
If a triple fault was fixed by kvm_x86_ops.nested_ops->triple_fault (by turning it into a vmexit), there is no need to leave vcpu_enter_guest(). Any vcpu->requests will be caught later before the actual vmentry, and in fact vcpu_enter_guest() was not initializing the "r" variable. Depending on the compiler's whims, this could cause the x86_64/triple_fault_event_test test to fail. Cc: Maxim Levitsky <mlevitsk@redhat.com> Fixes: 92e7d5c83aff ("KVM: x86: allow L1 to not intercept triple fault") Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-11-30ALSA: dice: fix regression for Lexicon I-ONIX FW810STakashi Sakamoto
For Lexicon I-ONIX FW810S, the call of ioctl(2) with SNDRV_PCM_IOCTL_HW_PARAMS can returns -ETIMEDOUT. This is a regression due to the commit 41319eb56e19 ("ALSA: dice: wait just for NOTIFY_CLOCK_ACCEPTED after GLOBAL_CLOCK_SELECT operation"). The device does not emit NOTIFY_CLOCK_ACCEPTED notification when accepting GLOBAL_CLOCK_SELECT operation with the same parameters as current ones. This commit fixes the regression. When receiving no notification, return -ETIMEDOUT as long as operating for any change. Fixes: 41319eb56e19 ("ALSA: dice: wait just for NOTIFY_CLOCK_ACCEPTED after GLOBAL_CLOCK_SELECT operation") Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Link: https://lore.kernel.org/r/20221130130604.29774-1-o-takashi@sakamocchi.jp Signed-off-by: Takashi Iwai <tiwai@suse.de>
2022-11-30drm/bridge: ti-sn65dsi86: Fix output polarity setting bugQiqi Zhang
According to the description in ti-sn65dsi86's datasheet: CHA_HSYNC_POLARITY: 0 = Active High Pulse. Synchronization signal is high for the sync pulse width. (default) 1 = Active Low Pulse. Synchronization signal is low for the sync pulse width. CHA_VSYNC_POLARITY: 0 = Active High Pulse. Synchronization signal is high for the sync pulse width. (Default) 1 = Active Low Pulse. Synchronization signal is low for the sync pulse width. We should only set these bits when the polarity is negative. Fixes: a095f15c00e2 ("drm/bridge: add support for sn65dsi86 bridge driver") Signed-off-by: Qiqi Zhang <eddy.zhang@rock-chips.com> Reviewed-by: Douglas Anderson <dianders@chromium.org> Tested-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://patchwork.freedesktop.org/patch/msgid/20221125104558.84616-1-eddy.zhang@rock-chips.com
2022-11-30nvme: fix SRCU protection of nvme_ns_head listCaleb Sander
Walking the nvme_ns_head siblings list is protected by the head's srcu in nvme_ns_head_submit_bio() but not nvme_mpath_revalidate_paths(). Removing namespaces from the list also fails to synchronize the srcu. Concurrent scan work can therefore cause use-after-frees. Hold the head's srcu lock in nvme_mpath_revalidate_paths() and synchronize with the srcu, not the global RCU, in nvme_ns_remove(). Observed the following panic when making NVMe/RDMA connections with native multipath on the Rocky Linux 8.6 kernel (it seems the upstream kernel has the same race condition). Disassembly shows the faulting instruction is cmp 0x50(%rdx),%rcx; computing capacity != get_capacity(ns->disk). Address 0x50 is dereferenced because ns->disk is NULL. The NULL disk appears to be the result of concurrent scan work freeing the namespace (note the log line in the middle of the panic). [37314.206036] BUG: unable to handle kernel NULL pointer dereference at 0000000000000050 [37314.206036] nvme0n3: detected capacity change from 0 to 11811160064 [37314.299753] PGD 0 P4D 0 [37314.299756] Oops: 0000 [#1] SMP PTI [37314.299759] CPU: 29 PID: 322046 Comm: kworker/u98:3 Kdump: loaded Tainted: G W X --------- - - 4.18.0-372.32.1.el8test86.x86_64 #1 [37314.299762] Hardware name: Dell Inc. PowerEdge R720/0JP31P, BIOS 2.7.0 05/23/2018 [37314.299763] Workqueue: nvme-wq nvme_scan_work [nvme_core] [37314.299783] RIP: 0010:nvme_mpath_revalidate_paths+0x26/0xb0 [nvme_core] [37314.299790] Code: 1f 44 00 00 66 66 66 66 90 55 53 48 8b 5f 50 48 8b 83 c8 c9 00 00 48 8b 13 48 8b 48 50 48 39 d3 74 20 48 8d 42 d0 48 8b 50 20 <48> 3b 4a 50 74 05 f0 80 60 70 ef 48 8b 50 30 48 8d 42 d0 48 39 d3 [37315.058803] RSP: 0018:ffffabe28f913d10 EFLAGS: 00010202 [37315.121316] RAX: ffff927a077da800 RBX: ffff92991dd70000 RCX: 0000000001600000 [37315.206704] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff92991b719800 [37315.292106] RBP: ffff929a6b70c000 R08: 000000010234cd4a R09: c0000000ffff7fff [37315.377501] R10: 0000000000000001 R11: ffffabe28f913a30 R12: 0000000000000000 [37315.462889] R13: ffff92992716600c R14: ffff929964e6e030 R15: ffff92991dd70000 [37315.548286] FS: 0000000000000000(0000) GS:ffff92b87fb80000(0000) knlGS:0000000000000000 [37315.645111] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [37315.713871] CR2: 0000000000000050 CR3: 0000002208810006 CR4: 00000000000606e0 [37315.799267] Call Trace: [37315.828515] nvme_update_ns_info+0x1ac/0x250 [nvme_core] [37315.892075] nvme_validate_or_alloc_ns+0x2ff/0xa00 [nvme_core] [37315.961871] ? __blk_mq_free_request+0x6b/0x90 [37316.015021] nvme_scan_work+0x151/0x240 [nvme_core] [37316.073371] process_one_work+0x1a7/0x360 [37316.121318] ? create_worker+0x1a0/0x1a0 [37316.168227] worker_thread+0x30/0x390 [37316.212024] ? create_worker+0x1a0/0x1a0 [37316.258939] kthread+0x10a/0x120 [37316.297557] ? set_kthread_struct+0x50/0x50 [37316.347590] ret_from_fork+0x35/0x40 [37316.390360] Modules linked in: nvme_rdma nvme_tcp(X) nvme_fabrics nvme_core netconsole iscsi_tcp libiscsi_tcp dm_queue_length dm_service_time nf_conntrack_netlink br_netfilter bridge stp llc overlay nft_chain_nat ipt_MASQUERADE nf_nat xt_addrtype xt_CT nft_counter xt_state xt_conntrack nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 xt_comment xt_multiport nft_compat nf_tables libcrc32c nfnetlink dm_multipath tg3 rpcrdma sunrpc rdma_ucm ib_srpt ib_isert iscsi_target_mod target_core_mod ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_cm ib_ipoib iw_cm ib_cm intel_rapl_msr iTCO_wdt iTCO_vendor_support dcdbas intel_rapl_common sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel ipmi_ssif kvm irqbypass crct10dif_pclmul crc32_pclmul mlx5_ib ghash_clmulni_intel ib_uverbs rapl intel_cstate intel_uncore ib_core ipmi_si joydev mei_me pcspkr ipmi_devintf mei lpc_ich wmi ipmi_msghandler acpi_power_meter ext4 mbcache jbd2 sd_mod t10_pi sg mgag200 mlx5_core drm_kms_helper syscopyarea [37316.390419] sysfillrect ahci sysimgblt fb_sys_fops libahci drm crc32c_intel libata mlxfw pci_hyperv_intf tls i2c_algo_bit psample dm_mirror dm_region_hash dm_log dm_mod fuse [last unloaded: nvme_core] [37317.645908] CR2: 0000000000000050 Fixes: e7d65803e2bb ("nvme-multipath: revalidate paths during rescan") Signed-off-by: Caleb Sander <csander@purestorage.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2022-11-30nvme-pci: clear the prp2 field when not usedLei Rao
If the prp2 field is not filled in nvme_setup_prp_simple(), the prp2 field is garbage data. According to nvme spec, the prp2 is reserved if the data transfer does not cross a memory page boundary, so clear it to zero if it is not used. Signed-off-by: Lei Rao <lei.rao@intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2022-11-30netfilter: ctnetlink: fix compilation warning after data race fixes in ct markPablo Neira Ayuso
All warnings (new ones prefixed by >>): net/netfilter/nf_conntrack_netlink.c: In function '__ctnetlink_glue_build': >> net/netfilter/nf_conntrack_netlink.c:2674:13: warning: unused variable 'mark' [-Wunused-variable] 2674 | u32 mark; | ^~~~ Fixes: 52d1aa8b8249 ("netfilter: conntrack: Fix data-races around ct mark") Reported-by: kernel test robot <lkp@intel.com> Tested-by: Ivan Babrou <ivan@ivan.computer> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2022-11-30netfilter: conntrack: fix using __this_cpu_add in preemptibleXin Long
Currently in nf_conntrack_hash_check_insert(), when it fails in nf_ct_ext_valid_pre/post(), NF_CT_STAT_INC() will be called in the preemptible context, a call trace can be triggered: BUG: using __this_cpu_add() in preemptible [00000000] code: conntrack/1636 caller is nf_conntrack_hash_check_insert+0x45/0x430 [nf_conntrack] Call Trace: <TASK> dump_stack_lvl+0x33/0x46 check_preemption_disabled+0xc3/0xf0 nf_conntrack_hash_check_insert+0x45/0x430 [nf_conntrack] ctnetlink_create_conntrack+0x3cd/0x4e0 [nf_conntrack_netlink] ctnetlink_new_conntrack+0x1c0/0x450 [nf_conntrack_netlink] nfnetlink_rcv_msg+0x277/0x2f0 [nfnetlink] netlink_rcv_skb+0x50/0x100 nfnetlink_rcv+0x65/0x144 [nfnetlink] netlink_unicast+0x1ae/0x290 netlink_sendmsg+0x257/0x4f0 sock_sendmsg+0x5f/0x70 This patch is to fix it by changing to use NF_CT_STAT_INC_ATOMIC() for nf_ct_ext_valid_pre/post() check in nf_conntrack_hash_check_insert(), as well as nf_ct_ext_valid_post() in __nf_conntrack_confirm(). Note that nf_ct_ext_valid_pre() check in __nf_conntrack_confirm() is safe to use NF_CT_STAT_INC(), as it's under local_bh_disable(). Fixes: c56716c69ce1 ("netfilter: extensions: introduce extension genid count") Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2022-11-30Add process name and pid to locks warningAndi Kleen
It's fairly useless to complain about using an obsolete feature without telling the user which process used it. My Fedora desktop randomly drops this message, but I would really need this patch to figure out what triggers is. [ jlayton: print pid as well as process name ] Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Jeff Layton <jlayton@kernel.org>
2022-11-30nfsd: use locks_inode_context helperJeff Layton
nfsd currently doesn't access i_flctx safely everywhere. This requires a smp_load_acquire, as the pointer is set via cmpxchg (a release operation). Acked-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jeff Layton <jlayton@kernel.org>
2022-11-30nfs: use locks_inode_context helperJeff Layton
nfs currently doesn't access i_flctx safely. This requires a smp_load_acquire, as the pointer is set via cmpxchg (a release operation). Cc: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: Anna Schumaker <anna@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jeff Layton <jlayton@kernel.org>
2022-11-30lockd: use locks_inode_context helperJeff Layton
lockd currently doesn't access i_flctx safely. This requires a smp_load_acquire, as the pointer is set via cmpxchg (a release operation). Cc: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: Anna Schumaker <anna@kernel.org> Cc: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jeff Layton <jlayton@kernel.org>
2022-11-30ksmbd: use locks_inode_context helperJeff Layton
ksmbd currently doesn't access i_flctx safely. This requires a smp_load_acquire, as the pointer is set via cmpxchg (a release operation). Cc: Steve French <sfrench@samba.org> Acked-by: Namjae Jeon <linkinjeon@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jeff Layton <jlayton@kernel.org>
2022-11-30cifs: use locks_inode_context helperJeff Layton
cifs currently doesn't access i_flctx safely. This requires a smp_load_acquire, as the pointer is set via cmpxchg (a release operation). Cc: Steve French <smfrench@samba.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jeff Layton <jlayton@kernel.org>
2022-11-30ceph: use locks_inode_context helperJeff Layton
ceph currently doesn't access i_flctx safely. This requires a smp_load_acquire, as the pointer is set via cmpxchg (a release operation). Reviewed-by: Xiubo Li <xiubli@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jeff Layton <jlayton@kernel.org>
2022-11-30filelock: add a new locks_inode_context accessor functionJeff Layton
There are a number of places in the kernel that are accessing the inode->i_flctx field without smp_load_acquire. This is required to ensure that the caller doesn't see a partially-initialized structure. Add a new accessor function for it to make this clear and convert all of the relevant accesses in locks.c to use it. Also, convert locks_free_lock_context to use the helper as well instead of just doing a "bare" assignment. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jeff Layton <jlayton@kernel.org>
2022-11-30filelock: new helper: vfs_inode_has_locksJeff Layton
Ceph has a need to know whether a particular inode has any locks set on it. It's currently tracking that by a num_locks field in its filp->private_data, but that's problematic as it tries to decrement this field when releasing locks and that can race with the file being torn down. Add a new vfs_inode_has_locks helper that just returns whether any locks are currently held on the inode. Reviewed-by: Xiubo Li <xiubli@redhat.com> Reviewed-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Jeff Layton <jlayton@kernel.org>
2022-11-29Merge patch series "riscv: kexec: Fxiup crash_save percpu and ↵Palmer Dabbelt
machine_kexec_mask_interrupts" guoren@kernel.org <guoren@kernel.org> says: From: Guo Ren <guoren@linux.alibaba.com> Current riscv kexec can't crash_save percpu states and disable interrupts properly. The patch series fix them, make kexec work correct. * b4-shazam-merge: riscv: kexec: Fixup crash_smp_send_stop without multi cores riscv: kexec: Fixup irq controller broken in kexec crash path Link: https://lore.kernel.org/r/20221020141603.2856206-1-guoren@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-11-29riscv: kexec: Fixup crash_smp_send_stop without multi coresGuo Ren
Current crash_smp_send_stop is the same as the generic one in kernel/panic and misses crash_save_cpu in percpu. This patch is inspired by 78fd584cdec0 ("arm64: kdump: implement machine_crash_shutdown()") and adds the same mechanism for riscv. Before this patch, test result: crash> help -r CPU 0: [OFFLINE] CPU 1: epc : ffffffff80009ff0 ra : ffffffff800b789a sp : ff2000001098bb40 gp : ffffffff815fca60 tp : ff60000004680000 t0 : 6666666666663c5b t1 : 0000000000000000 t2 : 666666666666663c s0 : ff2000001098bc90 s1 : ffffffff81600798 a0 : ff2000001098bb48 a1 : 0000000000000000 a2 : 0000000000000000 a3 : 0000000000000001 a4 : 0000000000000000 a5 : ff60000004690800 a6 : 0000000000000000 a7 : 0000000000000000 s2 : ff2000001098bb48 s3 : ffffffff81093ec8 s4 : ffffffff816004ac s5 : 0000000000000000 s6 : 0000000000000007 s7 : ffffffff80e7f720 s8 : 00fffffffffff3f0 s9 : 0000000000000007 s10: 00aaaaaaaab98700 s11: 0000000000000001 t3 : ffffffff819a8097 t4 : ffffffff819a8097 t5 : ffffffff819a8098 t6 : ff2000001098b9a8 CPU 2: [OFFLINE] CPU 3: [OFFLINE] After this patch, test result: crash> help -r CPU 0: epc : ffffffff80003f34 ra : ffffffff808caa7c sp : ffffffff81403eb0 gp : ffffffff815fcb48 tp : ffffffff81413400 t0 : 0000000000000000 t1 : 0000000000000000 t2 : 0000000000000000 s0 : ffffffff81403ec0 s1 : 0000000000000000 a0 : 0000000000000000 a1 : 0000000000000000 a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000 a5 : 0000000000000000 a6 : 0000000000000000 a7 : 0000000000000000 s2 : ffffffff816001c8 s3 : ffffffff81600370 s4 : ffffffff80c32e18 s5 : ffffffff819d3018 s6 : ffffffff810e2110 s7 : 0000000000000000 s8 : 0000000000000000 s9 : 0000000080039eac s10: 0000000000000000 s11: 0000000000000000 t3 : 0000000000000000 t4 : 0000000000000000 t5 : 0000000000000000 t6 : 0000000000000000 CPU 1: epc : ffffffff80003f34 ra : ffffffff808caa7c sp : ff2000000068bf30 gp : ffffffff815fcb48 tp : ff6000000240d400 t0 : 0000000000000000 t1 : 0000000000000000 t2 : 0000000000000000 s0 : ff2000000068bf40 s1 : 0000000000000001 a0 : 0000000000000000 a1 : 0000000000000000 a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000 a5 : 0000000000000000 a6 : 0000000000000000 a7 : 0000000000000000 s2 : ffffffff816001c8 s3 : ffffffff81600370 s4 : ffffffff80c32e18 s5 : ffffffff819d3018 s6 : ffffffff810e2110 s7 : 0000000000000000 s8 : 0000000000000000 s9 : 0000000080039ea8 s10: 0000000000000000 s11: 0000000000000000 t3 : 0000000000000000 t4 : 0000000000000000 t5 : 0000000000000000 t6 : 0000000000000000 CPU 2: epc : ffffffff80003f34 ra : ffffffff808caa7c sp : ff20000000693f30 gp : ffffffff815fcb48 tp : ff6000000240e900 t0 : 0000000000000000 t1 : 0000000000000000 t2 : 0000000000000000 s0 : ff20000000693f40 s1 : 0000000000000002 a0 : 0000000000000000 a1 : 0000000000000000 a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000 a5 : 0000000000000000 a6 : 0000000000000000 a7 : 0000000000000000 s2 : ffffffff816001c8 s3 : ffffffff81600370 s4 : ffffffff80c32e18 s5 : ffffffff819d3018 s6 : ffffffff810e2110 s7 : 0000000000000000 s8 : 0000000000000000 s9 : 0000000080039eb0 s10: 0000000000000000 s11: 0000000000000000 t3 : 0000000000000000 t4 : 0000000000000000 t5 : 0000000000000000 t6 : 0000000000000000 CPU 3: epc : ffffffff8000a1e4 ra : ffffffff800b7bba sp : ff200000109bbb40 gp : ffffffff815fcb48 tp : ff6000000373aa00 t0 : 6666666666663c5b t1 : 0000000000000000 t2 : 666666666666663c s0 : ff200000109bbc90 s1 : ffffffff816007a0 a0 : ff200000109bbb48 a1 : 0000000000000000 a2 : 0000000000000000 a3 : 0000000000000001 a4 : 0000000000000000 a5 : ff60000002c61c00 a6 : 0000000000000000 a7 : 0000000000000000 s2 : ff200000109bbb48 s3 : ffffffff810941a8 s4 : ffffffff816004b4 s5 : 0000000000000000 s6 : 0000000000000007 s7 : ffffffff80e7f7a0 s8 : 00fffffffffff3f0 s9 : 0000000000000007 s10: 00aaaaaaaab98700 s11: 0000000000000001 t3 : ffffffff819a8097 t4 : ffffffff819a8097 t5 : ffffffff819a8098 t6 : ff200000109bb9a8 Fixes: ad943893d5f1 ("RISC-V: Fixup schedule out issue in machine_crash_shutdown()") Reviewed-by: Xianting Tian <xianting.tian@linux.alibaba.com> Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Signed-off-by: Guo Ren <guoren@kernel.org> Cc: Nick Kossifidis <mick@ics.forth.gr> Link: https://lore.kernel.org/r/20221020141603.2856206-3-guoren@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-11-29riscv: kexec: Fixup irq controller broken in kexec crash pathGuo Ren
If a crash happens on cpu3 and all interrupts are binding on cpu0, the bad irq routing will cause a crash kernel which can't receive any irq. Because crash kernel won't clean up all harts' PLIC enable bits in enable registers. This patch is similar to 9141a003a491 ("ARM: 7316/1: kexec: EOI active and mask all interrupts in kexec crash path") and 78fd584cdec0 ("arm64: kdump: implement machine_crash_shutdown()"), and PowerPC also has the same mechanism. Fixes: fba8a8674f68 ("RISC-V: Add kexec support") Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Signed-off-by: Guo Ren <guoren@kernel.org> Reviewed-by: Xianting Tian <xianting.tian@linux.alibaba.com> Cc: Nick Kossifidis <mick@ics.forth.gr> Cc: Palmer Dabbelt <palmer@rivosinc.com> Link: https://lore.kernel.org/r/20221020141603.2856206-2-guoren@kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-11-29riscv: mm: Proper page permissions after initmem freeBjörn Töpel
64-bit RISC-V kernels have the kernel image mapped separately to alias the linear map. The linear map and the kernel image map are documented as "direct mapping" and "kernel" respectively in [1]. At image load time, the linear map corresponding to the kernel image is set to PAGE_READ permission, and the kernel image map is set to PAGE_READ|PAGE_EXEC. When the initmem is freed, the pages in the linear map should be restored to PAGE_READ|PAGE_WRITE, whereas the corresponding pages in the kernel image map should be restored to PAGE_READ, by removing the PAGE_EXEC permission. This is not the case. For 64-bit kernels, only the linear map is restored to its proper page permissions at initmem free, and not the kernel image map. In practise this results in that the kernel can potentially jump to dead __init code, and start executing invalid instructions, without getting an exception. Restore the freed initmem properly, by setting both the kernel image map to the correct permissions. [1] Documentation/riscv/vm-layout.rst Fixes: e5c35fa04019 ("riscv: Map the kernel with correct permissions the first time") Signed-off-by: Björn Töpel <bjorn@rivosinc.com> Reviewed-by: Alexandre Ghiti <alex@ghiti.fr> Tested-by: Alexandre Ghiti <alex@ghiti.fr> Link: https://lore.kernel.org/r/20221115090641.258476-1-bjorn@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-11-29riscv: vdso: fix section overlapping under some conditionsJisheng Zhang
lkp reported a build error, I tried the config and can reproduce build error as below: VDSOLD arch/riscv/kernel/vdso/vdso.so.dbg ld.lld: error: section .note file range overlaps with .text >>> .note range is [0x7C8, 0x803] >>> .text range is [0x800, 0x1993] ld.lld: error: section .text file range overlaps with .dynamic >>> .text range is [0x800, 0x1993] >>> .dynamic range is [0x808, 0x937] ld.lld: error: section .note virtual address range overlaps with .text >>> .note range is [0x7C8, 0x803] >>> .text range is [0x800, 0x1993] Fix it by setting DISABLE_BRANCH_PROFILING which will disable branch tracing for vdso, thus avoid useless _ftrace_annotated_branch section and _ftrace_branch section. Although we can also fix it by removing the hardcoded .text begin address, but I think that's another story and should be put into another patch. Link: https://lore.kernel.org/lkml/202210122123.Cc4FPShJ-lkp@intel.com/#r Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Link: https://lore.kernel.org/r/20221102170254.1925-1-jszhang@kernel.org Fixes: ad5d1122b82f ("riscv: use vDSO common flow to reduce the latency of the time-related functions") Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-11-29riscv: fix race when vmap stack overflowJisheng Zhang
Currently, when detecting vmap stack overflow, riscv firstly switches to the so called shadow stack, then use this shadow stack to call the get_overflow_stack() to get the overflow stack. However, there's a race here if two or more harts use the same shadow stack at the same time. To solve this race, we introduce spin_shadow_stack atomic var, which will be swap between its own address and 0 in atomic way, when the var is set, it means the shadow_stack is being used; when the var is cleared, it means the shadow_stack isn't being used. Fixes: 31da94c25aea ("riscv: add VMAP_STACK overflow detection") Signed-off-by: Jisheng Zhang <jszhang@kernel.org> Suggested-by: Guo Ren <guoren@kernel.org> Reviewed-by: Guo Ren <guoren@kernel.org> Link: https://lore.kernel.org/r/20221030124517.2370-1-jszhang@kernel.org [Palmer: Add AQ to the swap, and also some comments.] Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-11-29rcu: Make SRCU mandatoryPaul E. McKenney
Kernels configured with CONFIG_PRINTK=n and CONFIG_SRCU=n get build failures. This causes trouble for deep embedded systems. But given that there are more than 25 instances of "select SRCU" in the kernel, it is hard to believe that there are many kernels running in production without SRCU. This commit therefore makes SRCU mandatory. The SRCU Kconfig option remains for backwards compatibility, and will be removed when it is no longer used. [ paulmck: Update per kernel test robot feedback. ] Reported-by: John Ogness <john.ogness@linutronix.de> Reported-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: <linux-arch@vger.kernel.org> Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested Reviewed-by: John Ogness <john.ogness@linutronix.de>
2022-11-29scsi/scsi_error: Use call_rcu_hurry() instead of call_rcu()Uladzislau Rezki
Earlier commits in this series allow battery-powered systems to build their kernels with the default-disabled CONFIG_RCU_LAZY=y Kconfig option. This Kconfig option causes call_rcu() to delay its callbacks in order to batch them. This means that a given RCU grace period covers more callbacks, thus reducing the number of grace periods, in turn reducing the amount of energy consumed, which increases battery lifetime which can be a very good thing. This is not a subtle effect: In some important use cases, the battery lifetime is increased by more than 10%. This CONFIG_RCU_LAZY=y option is available only for CPUs that offload callbacks, for example, CPUs mentioned in the rcu_nocbs kernel boot parameter passed to kernels built with CONFIG_RCU_NOCB_CPU=y. Delaying callbacks is normally not a problem because most callbacks do nothing but free memory. If the system is short on memory, a shrinker will kick all currently queued lazy callbacks out of their laziness, thus freeing their memory in short order. Similarly, the rcu_barrier() function, which blocks until all currently queued callbacks are invoked, will also kick lazy callbacks, thus enabling rcu_barrier() to complete in a timely manner. However, there are some cases where laziness is not a good option. For example, synchronize_rcu() invokes call_rcu(), and blocks until the newly queued callback is invoked. It would not be a good for synchronize_rcu() to block for ten seconds, even on an idle system. Therefore, synchronize_rcu() invokes call_rcu_hurry() instead of call_rcu(). The arrival of a non-lazy call_rcu_hurry() callback on a given CPU kicks any lazy callbacks that might be already queued on that CPU. After all, if there is going to be a grace period, all callbacks might as well get full benefit from it. Yes, this could be done the other way around by creating a call_rcu_lazy(), but earlier experience with this approach and feedback at the 2022 Linux Plumbers Conference shifted the approach to call_rcu() being lazy with call_rcu_hurry() for the few places where laziness is inappropriate. And another call_rcu() instance that cannot be lazy is the one in the scsi_eh_scmd_add() function. Leaving this instance lazy results in unacceptably slow boot times. Therefore, make scsi_eh_scmd_add() use call_rcu_hurry() in order to revert to the old behavior. [ paulmck: Apply s/call_rcu_flush/call_rcu_hurry/ feedback from Tejun Heo. ] Tested-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Uladzislau Rezki <urezki@gmail.com> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Cc: "James E.J. Bottomley" <jejb@linux.ibm.com> Cc: <linux-scsi@vger.kernel.org> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Acked-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-11-29rcu/rcutorture: Use call_rcu_hurry() where neededJoel Fernandes (Google)
call_rcu() changes to save power will change the behavior of rcutorture tests. Use the call_rcu_hurry() API instead which reverts to the old behavior. [ paulmck: Apply s/call_rcu_flush/call_rcu_hurry/ feedback from Tejun Heo. ] Reported-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-11-29rcu/rcuscale: Use call_rcu_hurry() for async reader testJoel Fernandes (Google)
rcuscale uses call_rcu() to queue async readers. With recent changes to save power, the test will have fewer async readers in flight. Use the call_rcu_hurry() API instead to revert to the old behavior. [ paulmck: Apply s/call_rcu_flush/call_rcu_hurry/ feedback from Tejun Heo. ] Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>