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2016-03-25arch, ftrace: for KASAN put hard/soft IRQ entries into separate sectionsAlexander Potapenko
KASAN needs to know whether the allocation happens in an IRQ handler. This lets us strip everything below the IRQ entry point to reduce the number of unique stack traces needed to be stored. Move the definition of __irq_entry to <linux/interrupt.h> so that the users don't need to pull in <linux/ftrace.h>. Also introduce the __softirq_entry macro which is similar to __irq_entry, but puts the corresponding functions to the .softirqentry.text section. Signed-off-by: Alexander Potapenko <glider@google.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> 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: 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>
2016-03-25oom: clear TIF_MEMDIE after oom_reaper managed to unmap the address spaceMichal Hocko
When oom_reaper manages to unmap all the eligible vmas there shouldn't be much of the freable memory held by the oom victim left anymore so it makes sense to clear the TIF_MEMDIE flag for the victim and allow the OOM killer to select another task. The lack of TIF_MEMDIE also means that the victim cannot access memory reserves anymore but that shouldn't be a problem because it would get the access again if it needs to allocate and hits the OOM killer again due to the fatal_signal_pending resp. PF_EXITING check. We can safely hide the task from the OOM killer because it is clearly not a good candidate anymore as everyhing reclaimable has been torn down already. This patch will allow to cap the time an OOM victim can keep TIF_MEMDIE and thus hold off further global OOM killer actions granted the oom reaper is able to take mmap_sem for the associated mm struct. This is not guaranteed now but further steps should make sure that mmap_sem for write should be blocked killable which will help to reduce such a lock contention. This is not done by this patch. Note that exit_oom_victim might be called on a remote task from __oom_reap_task now so we have to check and clear the flag atomically otherwise we might race and underflow oom_victims or wake up waiters too early. Signed-off-by: Michal Hocko <mhocko@suse.com> Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Andrea Argangeli <andrea@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-25sched: add schedule_timeout_idle()Andrew Morton
This will be needed in the patch "mm, oom: introduce oom reaper". Acked-by: Michal Hocko <mhocko@suse.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-24Merge tag 'pm+acpi-4.6-rc1-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull more power management and ACPI updates from Rafael Wysocki: "The second batch of power management and ACPI updates for v4.6. Included are fixups on top of the previous PM/ACPI pull request and other material that didn't make into it but still should go into 4.6. Among other things, there's a fix for an intel_pstate driver issue uncovered by recent cpufreq changes, a workaround for a boot hang on Skylake-H related to the handling of deep C-states by the platform and a PCI/ACPI fix for the handling of IO port resources on non-x86 architectures plus some new device IDs and similar. Specifics: - Fix for an intel_pstate driver issue related to the handling of MSR updates uncovered by the recent cpufreq rework (Rafael Wysocki). - cpufreq core cleanups related to starting governors and frequency synchronization during resume from system suspend and a locking fix for cpufreq_quick_get() (Rafael Wysocki, Richard Cochran). - acpi-cpufreq and powernv cpufreq driver updates (Jisheng Zhang, Michael Neuling, Richard Cochran, Shilpasri Bhat). - intel_idle driver update preventing some Skylake-H systems from hanging during initialization by disabling deep C-states mishandled by the platform in the problematic configurations (Len Brown). - Intel Xeon Phi Processor x200 support for intel_idle (Dasaratharaman Chandramouli). - cpuidle menu governor updates to make it always honor PM QoS latency constraints (and prevent C1 from being used as the fallback C-state on x86 when they are set below its exit latency) and to restore the previous behavior to fall back to C1 if the next timer event is set far enough in the future that was changed in 4.4 which led to an energy consumption regression (Rik van Riel, Rafael Wysocki). - New device ID for a future AMD UART controller in the ACPI driver for AMD SoCs (Wang Hongcheng). - Rockchip rk3399 support for the rockchip-io-domain adaptive voltage scaling (AVS) driver (David Wu). - ACPI PCI resources management fix for the handling of IO space resources on architectures where the IO space is memory mapped (IA64 and ARM64) broken by the introduction of common ACPI resources parsing for PCI host bridges in 4.4 (Lorenzo Pieralisi). - Fix for the ACPI backend of the generic device properties API to make it parse non-device (data node only) children of an ACPI device correctly (Irina Tirdea). - Fixes for the handling of global suspend flags (introduced in 4.4) during hibernation and resume from it (Lukas Wunner). - Support for obtaining configuration information from Device Trees in the PM clocks framework (Jon Hunter). - ACPI _DSM helper code and devfreq framework cleanups (Colin Ian King, Geert Uytterhoeven)" * tag 'pm+acpi-4.6-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (23 commits) PM / AVS: rockchip-io: add io selectors and supplies for rk3399 intel_idle: Support for Intel Xeon Phi Processor x200 Product Family intel_idle: prevent SKL-H boot failure when C8+C9+C10 enabled ACPI / PM: Runtime resume devices when waking from hibernate PM / sleep: Clear pm_suspend_global_flags upon hibernate cpufreq: governor: Always schedule work on the CPU running update cpufreq: Always update current frequency before startig governor cpufreq: Introduce cpufreq_update_current_freq() cpufreq: Introduce cpufreq_start_governor() cpufreq: powernv: Add sysfs attributes to show throttle stats cpufreq: acpi-cpufreq: make Intel/AMD MSR access, io port access static PCI: ACPI: IA64: fix IO port generic range check ACPI / util: cast data to u64 before shifting to fix sign extension cpufreq: powernv: Define per_cpu chip pointer to optimize hot-path cpuidle: menu: Fall back to polling if next timer event is near cpufreq: acpi-cpufreq: Clean up hot plug notifier callback intel_pstate: Do not call wrmsrl_on_cpu() with disabled interrupts cpufreq: Make cpufreq_quick_get() safe to call ACPI / property: fix data node parsing in acpi_get_next_subnode() ACPI / APD: Add device HID for future AMD UART controller ...
2016-03-25Merge branches 'pm-avs', 'pm-clk', 'pm-devfreq' and 'pm-sleep'Rafael J. Wysocki
* pm-avs: PM / AVS: rockchip-io: add io selectors and supplies for rk3399 * pm-clk: PM / clk: Add support for obtaining clocks from device-tree * pm-devfreq: PM / devfreq: Spelling s/frequnecy/frequency/ * pm-sleep: ACPI / PM: Runtime resume devices when waking from hibernate PM / sleep: Clear pm_suspend_global_flags upon hibernate
2016-03-24Merge tag 'trace-v4.6' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing updates from Steven Rostedt: "Nothing major this round. Mostly small clean ups and fixes. Some visible changes: - A new flag was added to distinguish traces done in NMI context. - Preempt tracer now shows functions where preemption is disabled but interrupts are still enabled. Other notes: - Updates were done to function tracing to allow better performance with perf. - Infrastructure code has been added to allow for a new histogram feature for recording live trace event histograms that can be configured by simple user commands. The feature itself was just finished, but needs a round in linux-next before being pulled. This only includes some infrastructure changes that will be needed" * tag 'trace-v4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (22 commits) tracing: Record and show NMI state tracing: Fix trace_printk() to print when not using bprintk() tracing: Remove redundant reset per-CPU buff in irqsoff tracer x86: ftrace: Fix the misleading comment for arch/x86/kernel/ftrace.c tracing: Fix crash from reading trace_pipe with sendfile tracing: Have preempt(irqs)off trace preempt disabled functions tracing: Fix return while holding a lock in register_tracer() ftrace: Use kasprintf() in ftrace_profile_tracefs() ftrace: Update dynamic ftrace calls only if necessary ftrace: Make ftrace_hash_rec_enable return update bool tracing: Fix typoes in code comment and printk in trace_nop.c tracing, writeback: Replace cgroup path to cgroup ino tracing: Use flags instead of bool in trigger structure tracing: Add an unreg_all() callback to trigger commands tracing: Add needs_rec flag to event triggers tracing: Add a per-event-trigger 'paused' field tracing: Add get_syscall_name() tracing: Add event record param to trigger_ops.func() tracing: Make event trigger functions available tracing: Make ftrace_event_field checking functions available ...
2016-03-24Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Ingo Molnar: "This tree contains various perf fixes on the kernel side, plus three hw/event-enablement late additions: - Intel Memory Bandwidth Monitoring events and handling - the AMD Accumulated Power Mechanism reporting facility - more IOMMU events ... and a final round of perf tooling updates/fixes" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (44 commits) perf llvm: Use strerror_r instead of the thread unsafe strerror one perf llvm: Use realpath to canonicalize paths perf tools: Unexport some methods unused outside strbuf.c perf probe: No need to use formatting strbuf method perf help: Use asprintf instead of adhoc equivalents perf tools: Remove unused perf_pathdup, xstrdup functions perf tools: Do not include stringify.h from the kernel sources tools include: Copy linux/stringify.h from the kernel tools lib traceevent: Remove redundant CPU output perf tools: Remove needless 'extern' from function prototypes perf tools: Simplify die() mechanism perf tools: Remove unused DIE_IF macro perf script: Remove lots of unused arguments perf thread: Rename perf_event__preprocess_sample_addr to thread__resolve perf machine: Rename perf_event__preprocess_sample to machine__resolve perf tools: Add cpumode to struct perf_sample perf tests: Forward the perf_sample in the dwarf unwind test perf tools: Remove misplaced __maybe_unused perf list: Fix documentation of :ppp perf bench numa: Fix assertion for nodes bitfield ...
2016-03-24Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Ingo Molnar: "Misc fixes: a cgroup fix, a fair-scheduler migration accounting fix, a cputime fix and two cpuacct cleanups" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/cpuacct: Simplify the cpuacct code sched/cpuacct: Rename parameter in cpuusage_write() for readability sched/fair: Add comments to explain select_idle_sibling() sched/fair: Fix fairness issue on migration sched/cgroup: Fix/cleanup cgroup teardown/init sched/cputime: Fix steal time accounting vs. CPU hotplug
2016-03-23PM / sleep: Clear pm_suspend_global_flags upon hibernateLukas Wunner
When suspending to RAM, waking up and later suspending to disk, we gratuitously runtime resume devices after the thaw phase. This does not occur if we always suspend to RAM or always to disk. pm_complete_with_resume_check(), which gets called from pci_pm_complete() among others, schedules a runtime resume if PM_SUSPEND_FLAG_FW_RESUME is set. The flag is set during a suspend-to-RAM cycle. It is cleared at the beginning of the suspend-to-RAM cycle but not afterwards and it is not cleared during a suspend-to-disk cycle at all. Fix it. Fixes: ef25ba047601 (PM / sleep: Add flags to indicate platform firmware involvement) Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: 4.4+ <stable@vger.kernel.org> # 4.4+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-03-22kernel/...: convert pr_warning to pr_warnJoe Perches
Use the more common logging method with the eventual goal of removing pr_warning altogether. Miscellanea: - Realign arguments - Coalesce formats - Add missing space between a few coalesced formats Signed-off-by: Joe Perches <joe@perches.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> [kernel/power/suspend.c] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22memremap: add MEMREMAP_WC flagBrian Starkey
Add a flag to memremap() for writecombine mappings. Mappings satisfied by this flag will not be cached, however writes may be delayed or combined into more efficient bursts. This is most suitable for buffers written sequentially by the CPU for use by other DMA devices. Signed-off-by: Brian Starkey <brian.starkey@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22memremap: don't modify flagsBrian Starkey
These patches implement a MEMREMAP_WC flag for memremap(), which can be used to obtain writecombine mappings. This is then used for setting up dma_coherent_mem regions which use the DMA_MEMORY_MAP flag. The motivation is to fix an alignment fault on arm64, and the suggestion to implement MEMREMAP_WC for this case was made at [1]. That particular issue is handled in patch 4, which makes sure that the appropriate memset function is used when zeroing allocations mapped as IO memory. This patch (of 4): Don't modify the flags input argument to memremap(). MEMREMAP_WB is already a special case so we can check for it directly instead of clearing flag bits in each mapper. Signed-off-by: Brian Starkey <brian.starkey@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22kernel/signal.c: add compile-time check for __ARCH_SI_PREAMBLE_SIZEHelge Deller
The value of __ARCH_SI_PREAMBLE_SIZE defines the size (including padding) of the part of the struct siginfo that is before the union, and it is then used to calculate the needed padding (SI_PAD_SIZE) to make the size of struct siginfo equal to 128 (SI_MAX_SIZE) bytes. Depending on the target architecture and word width it equals to either 3 or 4 times sizeof int. Since the very beginning we had __ARCH_SI_PREAMBLE_SIZE wrong on the parisc architecture for the 64bit kernel build. It's even more frustrating, because it can easily be checked at compile time if the value was defined correctly. This patch adds such a check for the correctness of __ARCH_SI_PREAMBLE_SIZE in the hope that it will prevent existing and future architectures from running into the same problem. I refrained from replacing __ARCH_SI_PREAMBLE_SIZE by offsetof() in copy_siginfo() in include/asm-generic/siginfo.h, because a) it doesn't make any difference and b) it's used in the Documentation/kmemcheck.txt example. I ran this patch through the 0-DAY kernel test infrastructure and only the parisc architecture triggered as expected. That means that this patch should be OK for all major architectures. Signed-off-by: Helge Deller <deller@gmx.de> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Oleg Nesterov <oleg@redhat.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>
2016-03-22profile: hide unused functions when !CONFIG_PROC_FSArnd Bergmann
A couple of functions and variables in the profile implementation are used only on SMP systems by the procfs code, but are unused if either procfs is disabled or in uniprocessor kernels. gcc prints a harmless warning about the unused symbols: kernel/profile.c:243:13: error: 'profile_flip_buffers' defined but not used [-Werror=unused-function] static void profile_flip_buffers(void) ^ kernel/profile.c:266:13: error: 'profile_discard_flip_buffers' defined but not used [-Werror=unused-function] static void profile_discard_flip_buffers(void) ^ kernel/profile.c:330:12: error: 'profile_cpu_callback' defined but not used [-Werror=unused-function] static int profile_cpu_callback(struct notifier_block *info, ^ This adds further #ifdef to the file, to annotate exactly in which cases they are used. I have done several thousand ARM randconfig kernels with this patch applied and no longer get any warnings in this file. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Robin Holt <robinmholt@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Lameter <cl@linux.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22panic: change nmi_panic from macro to functionHidehiro Kawai
Commit 1717f2096b54 ("panic, x86: Fix re-entrance problem due to panic on NMI") and commit 58c5661f2144 ("panic, x86: Allow CPUs to save registers even if looping in NMI context") introduced nmi_panic() which prevents concurrent/recursive execution of panic(). It also saves registers for the crash dump on x86. However, there are some cases where NMI handlers still use panic(). This patch set partially replaces them with nmi_panic() in those cases. Even this patchset is applied, some NMI or similar handlers (e.g. MCE handler) continue to use panic(). This is because I can't test them well and actual problems won't happen. For example, the possibility that normal panic and panic on MCE happen simultaneously is very low. This patch (of 3): Convert nmi_panic() to a proper function and export it instead of exporting internal implementation details to modules, for obvious reasons. Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com> Acked-by: Borislav Petkov <bp@suse.de> Acked-by: Michal Nazarewicz <mina86@mina86.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Nicolas Iooss <nicolas.iooss_linux@m4x.org> Cc: Javi Merino <javi.merino@arm.com> Cc: Gobinda Charan Maji <gobinda.cemk07@gmail.com> Cc: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22fs/coredump: prevent fsuid=0 dumps into user-controlled directoriesJann Horn
This commit fixes the following security hole affecting systems where all of the following conditions are fulfilled: - The fs.suid_dumpable sysctl is set to 2. - The kernel.core_pattern sysctl's value starts with "/". (Systems where kernel.core_pattern starts with "|/" are not affected.) - Unprivileged user namespace creation is permitted. (This is true on Linux >=3.8, but some distributions disallow it by default using a distro patch.) Under these conditions, if a program executes under secure exec rules, causing it to run with the SUID_DUMP_ROOT flag, then unshares its user namespace, changes its root directory and crashes, the coredump will be written using fsuid=0 and a path derived from kernel.core_pattern - but this path is interpreted relative to the root directory of the process, allowing the attacker to control where a coredump will be written with root privileges. To fix the security issue, always interpret core_pattern for dumps that are written under SUID_DUMP_ROOT relative to the root directory of init. Signed-off-by: Jann Horn <jann@thejh.net> Acked-by: Kees Cook <keescook@chromium.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22ptrace: change __ptrace_unlink() to clear ->ptrace under ->siglockOleg Nesterov
This test-case (simplified version of generated by syzkaller) #include <unistd.h> #include <sys/ptrace.h> #include <sys/wait.h> void test(void) { for (;;) { if (fork()) { wait(NULL); continue; } ptrace(PTRACE_SEIZE, getppid(), 0, 0); ptrace(PTRACE_INTERRUPT, getppid(), 0, 0); _exit(0); } } int main(void) { int np; for (np = 0; np < 8; ++np) if (!fork()) test(); while (wait(NULL) > 0) ; return 0; } triggers the 2nd WARN_ON_ONCE(!signr) warning in do_jobctl_trap(). The problem is that __ptrace_unlink() clears task->jobctl under siglock but task->ptrace is cleared without this lock held; this fools the "else" branch which assumes that !PT_SEIZED means PT_PTRACED. Note also that most of other PTRACE_SEIZE checks can race with detach from the exiting tracer too. Say, the callers of ptrace_trap_notify() assume that SEIZED can't go away after it was checked. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: syzkaller <syzkaller@googlegroups.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22auditsc: for seccomp events, log syscall compat state using in_compat_syscallAndy Lutomirski
Except on SPARC, this is what the code always did. SPARC compat seccomp was buggy, although the impact of the bug was limited because SPARC 32-bit and 64-bit syscall numbers are the same. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Paul Moore <paul@paul-moore.com> Cc: Eric Paris <eparis@redhat.com> Cc: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22ptrace: in PEEK_SIGINFO, check syscall bitness, not task bitnessAndy Lutomirski
Users of the 32-bit ptrace() ABI expect the full 32-bit ABI. siginfo translation should check ptrace() ABI, not caller task ABI. This is an ABI change on SPARC. Let's hope that no one relied on the old buggy ABI. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22seccomp: check in_compat_syscall, not is_compat_task, in strict modeAndy Lutomirski
Seccomp wants to know the syscall bitness, not the caller task bitness, when it selects the syscall whitelist. As far as I know, this makes no difference on any architecture, so it's not a security problem. (It generates identical code everywhere except sparc, and, on sparc, the syscall numbering is the same for both ABIs.) Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22kernel/hung_task.c: use timeout diff when timeout is updatedTetsuo Handa
When new timeout is written to /proc/sys/kernel/hung_task_timeout_secs, khungtaskd is interrupted and again sleeps for full timeout duration. This means that hang task will not be checked if new timeout is written periodically within old timeout duration and/or checking of hang task will be delayed for up to previous timeout duration. Fix this by remembering last time khungtaskd checked hang task. This change will allow other watchdog tasks (if any) to share khungtaskd by sleeping for minimal timeout diff of all watchdog tasks. Doing more watchdog tasks from khungtaskd will reduce the possibility of printk() collisions by multiple watchdog threads. Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-22tracing: Record and show NMI statePeter Zijlstra
The latency tracer format has a nice column to indicate IRQ state, but this is not able to tell us about NMI state. When tracing perf interrupt handlers (which often run in NMI context) it is very useful to see how the events nest. Link: http://lkml.kernel.org/r/20160318153022.105068893@infradead.org Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-22tracing: Fix trace_printk() to print when not using bprintk()Steven Rostedt (Red Hat)
The trace_printk() code will allocate extra buffers if the compile detects that a trace_printk() is used. To do this, the format of the trace_printk() is saved to the __trace_printk_fmt section, and if that section is bigger than zero, the buffers are allocated (along with a message that this has happened). If trace_printk() uses a format that is not a constant, and thus something not guaranteed to be around when the print happens, the compiler optimizes the fmt out, as it is not used, and the __trace_printk_fmt section is not filled. This means the kernel will not allocate the special buffers needed for the trace_printk() and the trace_printk() will not write anything to the tracing buffer. Adding a "__used" to the variable in the __trace_printk_fmt section will keep it around, even though it is set to NULL. This will keep the string from being printed in the debugfs/tracing/printk_formats section as it is not needed. Reported-by: Vlastimil Babka <vbabka@suse.cz> Fixes: 07d777fe8c398 "tracing: Add percpu buffers for trace_printk()" Cc: stable@vger.kernel.org # v3.5+ Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-21Merge branch 'for-4.6-ns' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup namespace support from Tejun Heo: "These are changes to implement namespace support for cgroup which has been pending for quite some time now. It is very straight-forward and only affects what part of cgroup hierarchies are visible. After unsharing, mounting a cgroup fs will be scoped to the cgroups the task belonged to at the time of unsharing and the cgroup paths exposed to userland would be adjusted accordingly" * 'for-4.6-ns' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: fix and restructure error handling in copy_cgroup_ns() cgroup: fix alloc_cgroup_ns() error handling in copy_cgroup_ns() Add FS_USERNS_FLAG to cgroup fs cgroup: Add documentation for cgroup namespaces cgroup: mount cgroupns-root when inside non-init cgroupns kernfs: define kernfs_node_dentry cgroup: cgroup namespace setns support cgroup: introduce cgroup namespaces sched: new clone flag CLONE_NEWCGROUP for cgroup namespace kernfs: Add API to generate relative kernfs path
2016-03-21sched/cpuacct: Simplify the cpuacct codeZhao Lei
- Use for() instead of while() loop in some functions to make the code simpler. - Use this_cpu_ptr() instead of per_cpu_ptr() to make the code cleaner and a bit faster. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Tejun Heo <htejun@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/d8a7ef9592f55224630cb26dea239f05b6398a4e.1458187654.git.zhaolei@cn.fujitsu.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-21sched/cpuacct: Rename parameter in cpuusage_write() for readabilityDongsheng Yang
The name of the 'reset' parameter to cpuusage_write() is quite confusing, because the only valid value we allow is '0', so !reset is actually the case that resets ... Rename it to 'val' and explain it in a comment that we only allow 0. Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: cgroups@vger.kernel.org Cc: tj@kernel.org Link: http://lkml.kernel.org/r/1450696483-2864-1-git-send-email-yangds.fnst@cn.fujitsu.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-21sched/fair: Add comments to explain select_idle_sibling()Matt Fleming
It's not entirely obvious how the main loop in select_idle_sibling() works on first glance. Sprinkle a few comments to explain the design and intention behind the loop based on some conversations with Mike and Peter. Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.com> Cc: Mike Galbraith <mgalbraith@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1457535548-15329-1-git-send-email-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-21sched/fair: Fix fairness issue on migrationPeter Zijlstra
Pavan reported that in the presence of very light tasks (or cgroups) the placement of migrated tasks can cause severe fairness issues. The problem is that enqueue_entity() places the task before it updates time, thereby it can place the task far in the past (remember that light tasks will shoot virtual time forward at a high speed, so in relation to the pre-existing light task, we can land far in the past). This is done because update_curr() needs the current task, and we might be placing the current task. The obvious solution is to differentiate between the current and any other task; placing the current before we update time, and placing any other task after, such that !curr tasks end up at the current moment in time, and not in the past. Reported-by: Pavan Kondeti <pkondeti@codeaurora.org> Tested-by: Pavan Kondeti <pkondeti@codeaurora.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Ben Segall <bsegall@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: byungchul.park@lge.com Link: http://lkml.kernel.org/r/20160309120403.GK6344@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-21sched/cgroup: Fix/cleanup cgroup teardown/initPeter Zijlstra
The CPU controller hasn't kept up with the various changes in the whole cgroup initialization / destruction sequence, and commit: 2e91fa7f6d45 ("cgroup: keep zombies associated with their original cgroups") caused it to explode. The reason for this is that zombies do not inhibit css_offline() from being called, but do stall css_released(). Now we tear down the cfs_rq structures on css_offline() but zombies can run after that, leading to use-after-free issues. The solution is to move the tear-down to css_released(), which guarantees nobody (including no zombies) is still using our cgroup. Furthermore, a few simple cleanups are possible too. There doesn't appear to be any point to us using css_online() (anymore?) so fold that in css_alloc(). And since cgroup code guarantees an RCU grace period between css_released() and css_free() we can forgo using call_rcu() and free the stuff immediately. Suggested-by: Tejun Heo <tj@kernel.org> Reported-by: Kazuki Yamaguchi <k@rhe.jp> Reported-by: Niklas Cassel <niklas.cassel@axis.com> Tested-by: Niklas Cassel <niklas.cassel@axis.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Tejun Heo <tj@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 2e91fa7f6d45 ("cgroup: keep zombies associated with their original cgroups") Link: http://lkml.kernel.org/r/20160316152245.GY6344@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-21Merge branch 'linus' into sched/urgent, to pick up dependenciesIngo Molnar
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-21perf/core: Document some hotplug bitsPeter Zijlstra
Document some of the hotplug notifier usage. Requested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David Ahern <dsahern@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-21perf/core: Fix Undefined behaviour in rb_alloc()Peter Zijlstra
Sasha reported: [ 3494.030114] UBSAN: Undefined behaviour in kernel/events/ring_buffer.c:685:22 [ 3494.030647] shift exponent -1 is negative Andrey spotted that this is because: It happens if nr_pages = 0: rb->page_order = ilog2(nr_pages); Fix it by making both assignments conditional on nr_pages; since otherwise they should both be 0 anyway, and will be because of the kzalloc() used to allocate the structure. Reported-by: Sasha Levin <sasha.levin@oracle.com> Reported-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David Ahern <dsahern@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Link: http://lkml.kernel.org/r/20160129141751.GA407@worktop Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-21perf/core: Fix dynamic interrupt throttlePeter Zijlstra
There were two problems with the dynamic interrupt throttle mechanism, both triggered by the same action. When you (or perf_fuzzer) write a huge value into /proc/sys/kernel/perf_event_max_sample_rate the computed perf_sample_allowed_ns becomes 0. This effectively disables the whole dynamic throttle. This is fixed by ensuring update_perf_cpu_limits() never sets the value to 0. However, we allow disabling of the dynamic throttle by writing 100 to /proc/sys/kernel/perf_cpu_time_max_percent. This will generate a warning in dmesg. The second problem is that by setting the max_sample_rate to a huge number, the adaptive process can take a few tries, since it halfs the limit each time. Change that to directly compute a new value based on the observed duration. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David Ahern <dsahern@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-21perf/core: Fix the unthrottle logicPeter Zijlstra
Its possible to IOC_PERIOD while the event is throttled, this would re-start the event and the next tick would then try to unthrottle it, and find the event wasn't actually stopped anymore. This would tickle a WARN in the x86-pmu code which isn't expecting to start a !stopped event. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David Ahern <dsahern@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: dvyukov@google.com Cc: oleg@redhat.com Cc: panand@redhat.com Cc: sasha.levin@oracle.com Cc: vince@deater.net Link: http://lkml.kernel.org/r/20160310143924.GR6356@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-20Merge branch 'mm-pkeys-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 protection key support from Ingo Molnar: "This tree adds support for a new memory protection hardware feature that is available in upcoming Intel CPUs: 'protection keys' (pkeys). There's a background article at LWN.net: https://lwn.net/Articles/643797/ The gist is that protection keys allow the encoding of user-controllable permission masks in the pte. So instead of having a fixed protection mask in the pte (which needs a system call to change and works on a per page basis), the user can map a (handful of) protection mask variants and can change the masks runtime relatively cheaply, without having to change every single page in the affected virtual memory range. This allows the dynamic switching of the protection bits of large amounts of virtual memory, via user-space instructions. It also allows more precise control of MMU permission bits: for example the executable bit is separate from the read bit (see more about that below). This tree adds the MM infrastructure and low level x86 glue needed for that, plus it adds a high level API to make use of protection keys - if a user-space application calls: mmap(..., PROT_EXEC); or mprotect(ptr, sz, PROT_EXEC); (note PROT_EXEC-only, without PROT_READ/WRITE), the kernel will notice this special case, and will set a special protection key on this memory range. It also sets the appropriate bits in the Protection Keys User Rights (PKRU) register so that the memory becomes unreadable and unwritable. So using protection keys the kernel is able to implement 'true' PROT_EXEC on x86 CPUs: without protection keys PROT_EXEC implies PROT_READ as well. Unreadable executable mappings have security advantages: they cannot be read via information leaks to figure out ASLR details, nor can they be scanned for ROP gadgets - and they cannot be used by exploits for data purposes either. We know about no user-space code that relies on pure PROT_EXEC mappings today, but binary loaders could start making use of this new feature to map binaries and libraries in a more secure fashion. There is other pending pkeys work that offers more high level system call APIs to manage protection keys - but those are not part of this pull request. Right now there's a Kconfig that controls this feature (CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS) that is default enabled (like most x86 CPU feature enablement code that has no runtime overhead), but it's not user-configurable at the moment. If there's any serious problem with this then we can make it configurable and/or flip the default" * 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (38 commits) x86/mm/pkeys: Fix mismerge of protection keys CPUID bits mm/pkeys: Fix siginfo ABI breakage caused by new u64 field x86/mm/pkeys: Fix access_error() denial of writes to write-only VMA mm/core, x86/mm/pkeys: Add execute-only protection keys support x86/mm/pkeys: Create an x86 arch_calc_vm_prot_bits() for VMA flags x86/mm/pkeys: Allow kernel to modify user pkey rights register x86/fpu: Allow setting of XSAVE state x86/mm: Factor out LDT init from context init mm/core, x86/mm/pkeys: Add arch_validate_pkey() mm/core, arch, powerpc: Pass a protection key in to calc_vm_flag_bits() x86/mm/pkeys: Actually enable Memory Protection Keys in the CPU x86/mm/pkeys: Add Kconfig prompt to existing config option x86/mm/pkeys: Dump pkey from VMA in /proc/pid/smaps x86/mm/pkeys: Dump PKRU with other kernel registers mm/core, x86/mm/pkeys: Differentiate instruction fetches x86/mm/pkeys: Optimize fault handling in access_error() mm/core: Do not enforce PKEY permissions on remote mm access um, pkeys: Add UML arch_*_access_permitted() methods mm/gup, x86/mm/pkeys: Check VMAs and PTEs for protection keys x86/mm/gup: Simplify get_user_pages() PTE bit handling ...
2016-03-20Merge branch 'core-objtool-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull 'objtool' stack frame validation from Ingo Molnar: "This tree adds a new kernel build-time object file validation feature (ONFIG_STACK_VALIDATION=y): kernel stack frame correctness validation. It was written by and is maintained by Josh Poimboeuf. The motivation: there's a category of hard to find kernel bugs, most of them in assembly code (but also occasionally in C code), that degrades the quality of kernel stack dumps/backtraces. These bugs are hard to detect at the source code level. Such bugs result in incorrect/incomplete backtraces most of time - but can also in some rare cases result in crashes or other undefined behavior. The build time correctness checking is done via the new 'objtool' user-space utility that was written for this purpose and which is hosted in the kernel repository in tools/objtool/. The tool's (very simple) UI and source code design is shaped after Git and perf and shares quite a bit of infrastructure with tools/perf (which tooling infrastructure sharing effort got merged via perf and is already upstream). Objtool follows the well-known kernel coding style. Objtool does not try to check .c or .S files, it instead analyzes the resulting .o generated machine code from first principles: it decodes the instruction stream and interprets it. (Right now objtool supports the x86-64 architecture.) From tools/objtool/Documentation/stack-validation.txt: "The kernel CONFIG_STACK_VALIDATION option enables a host tool named objtool which runs at compile time. It has a "check" subcommand which analyzes every .o file and ensures the validity of its stack metadata. It enforces a set of rules on asm code and C inline assembly code so that stack traces can be reliable. Currently it only checks frame pointer usage, but there are plans to add CFI validation for C files and CFI generation for asm files. For each function, it recursively follows all possible code paths and validates the correct frame pointer state at each instruction. It also follows code paths involving special sections, like .altinstructions, __jump_table, and __ex_table, which can add alternative execution paths to a given instruction (or set of instructions). Similarly, it knows how to follow switch statements, for which gcc sometimes uses jump tables." When this new kernel option is enabled (it's disabled by default), the tool, if it finds any suspicious assembly code pattern, outputs warnings in compiler warning format: warning: objtool: rtlwifi_rate_mapping()+0x2e7: frame pointer state mismatch warning: objtool: cik_tiling_mode_table_init()+0x6ce: call without frame pointer save/setup warning: objtool:__schedule()+0x3c0: duplicate frame pointer save warning: objtool:__schedule()+0x3fd: sibling call from callable instruction with changed frame pointer ... so that scripts that pick up compiler warnings will notice them. All known warnings triggered by the tool are fixed by the tree, most of the commits in fact prepare the kernel to be warning-free. Most of them are bugfixes or cleanups that stand on their own, but there are also some annotations of 'special' stack frames for justified cases such entries to JIT-ed code (BPF) or really special boot time code. There are two other long-term motivations behind this tool as well: - To improve the quality and reliability of kernel stack frames, so that they can be used for optimized live patching. - To create independent infrastructure to check the correctness of CFI stack frames at build time. CFI debuginfo is notoriously unreliable and we cannot use it in the kernel as-is without extra checking done both on the kernel side and on the build side. The quality of kernel stack frames matters to debuggability as well, so IMO we can merge this without having to consider the live patching or CFI debuginfo angle" * 'core-objtool-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits) objtool: Only print one warning per function objtool: Add several performance improvements tools: Copy hashtable.h into tools directory objtool: Fix false positive warnings for functions with multiple switch statements objtool: Rename some variables and functions objtool: Remove superflous INIT_LIST_HEAD objtool: Add helper macros for traversing instructions objtool: Fix false positive warnings related to sibling calls objtool: Compile with debugging symbols objtool: Detect infinite recursion objtool: Prevent infinite recursion in noreturn detection objtool: Detect and warn if libelf is missing and don't break the build tools: Support relative directory path for 'O=' objtool: Support CROSS_COMPILE x86/asm/decoder: Use explicitly signed chars objtool: Enable stack metadata validation on 64-bit x86 objtool: Add CONFIG_STACK_VALIDATION option objtool: Add tool to perform compile-time stack metadata validation x86/kprobes: Mark kretprobe_trampoline() stack frame as non-standard sched: Always inline context_switch() ...
2016-03-19Merge branch 'stable-4.6' of git://git.infradead.org/users/pcmoore/auditLinus Torvalds
Pull audit updates from Paul Moore: "A small set of patches for audit this time; just three in total and one is a spelling fix. The two patches with actual content are designed to help prevent new instances of auditd from displacing an existing, functioning auditd and to generate a log of the attempt. Not to worry, dead/stuck auditd instances can still be replaced by a new instance without problem. Nothing controversial, and everything passes our regression suite" * 'stable-4.6' of git://git.infradead.org/users/pcmoore/audit: audit: Fix typo in comment audit: log failed attempts to change audit_pid configuration audit: stop an old auditd being starved out by a new auditd
2016-03-19Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-nextLinus Torvalds
Pull networking updates from David Miller: "Highlights: 1) Support more Realtek wireless chips, from Jes Sorenson. 2) New BPF types for per-cpu hash and arrap maps, from Alexei Starovoitov. 3) Make several TCP sysctls per-namespace, from Nikolay Borisov. 4) Allow the use of SO_REUSEPORT in order to do per-thread processing of incoming TCP/UDP connections. The muxing can be done using a BPF program which hashes the incoming packet. From Craig Gallek. 5) Add a multiplexer for TCP streams, to provide a messaged based interface. BPF programs can be used to determine the message boundaries. From Tom Herbert. 6) Add 802.1AE MACSEC support, from Sabrina Dubroca. 7) Avoid factorial complexity when taking down an inetdev interface with lots of configured addresses. We were doing things like traversing the entire address less for each address removed, and flushing the entire netfilter conntrack table for every address as well. 8) Add and use SKB bulk free infrastructure, from Jesper Brouer. 9) Allow offloading u32 classifiers to hardware, and implement for ixgbe, from John Fastabend. 10) Allow configuring IRQ coalescing parameters on a per-queue basis, from Kan Liang. 11) Extend ethtool so that larger link mode masks can be supported. From David Decotigny. 12) Introduce devlink, which can be used to configure port link types (ethernet vs Infiniband, etc.), port splitting, and switch device level attributes as a whole. From Jiri Pirko. 13) Hardware offload support for flower classifiers, from Amir Vadai. 14) Add "Local Checksum Offload". Basically, for a tunneled packet the checksum of the outer header is 'constant' (because with the checksum field filled into the inner protocol header, the payload of the outer frame checksums to 'zero'), and we can take advantage of that in various ways. From Edward Cree" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1548 commits) bonding: fix bond_get_stats() net: bcmgenet: fix dma api length mismatch net/mlx4_core: Fix backward compatibility on VFs phy: mdio-thunder: Fix some Kconfig typos lan78xx: add ndo_get_stats64 lan78xx: handle statistics counter rollover RDS: TCP: Remove unused constant RDS: TCP: Add sysctl tunables for sndbuf/rcvbuf on rds-tcp socket net: smc911x: convert pxa dma to dmaengine team: remove duplicate set of flag IFF_MULTICAST bonding: remove duplicate set of flag IFF_MULTICAST net: fix a comment typo ethernet: micrel: fix some error codes ip_tunnels, bpf: define IP_TUNNEL_OPTS_MAX and use it bpf, dst: add and use dst_tclassid helper bpf: make skb->tc_classid also readable net: mvneta: bm: clarify dependencies cls_bpf: reset class and reuse major in da ldmvsw: Checkpatch sunvnet.c and sunvnet_common.c ldmvsw: Add ldmvsw.c driver code ...
2016-03-18Merge branch 'for-4.6' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: "cgroup changes for v4.6-rc1. No userland visible behavior changes in this pull request. I'll send out a separate pull request for the addition of cgroup namespace support. - The biggest change is the revamping of cgroup core task migration and controller handling logic. There are quite a few places where controllers and tasks are manipulated. Previously, many of those places implemented custom operations for each specific use case assuming specific starting conditions. While this worked, it makes the code fragile and difficult to follow. The bulk of this pull request restructures these operations so that most related operations are performed through common helpers which implement recursive (subtrees are always processed consistently) and idempotent (they make cgroup hierarchy converge to the target state rather than performing operations assuming specific starting conditions). This makes the code a lot easier to understand, verify and extend. - Implicit controller support is added. This is primarily for using perf_event on the v2 hierarchy so that perf can match cgroup v2 path without requiring the user to do anything special. The kernel portion of perf_event changes is acked but userland changes are still pending review. - cgroup_no_v1= boot parameter added to ease testing cgroup v2 in certain environments. - There is a regression introduced during v4.4 devel cycle where attempts to migrate zombie tasks can mess up internal object management. This was fixed earlier this week and included in this pull request w/ stable cc'd. - Misc non-critical fixes and improvements" * 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (44 commits) cgroup: avoid false positive gcc-6 warning cgroup: ignore css_sets associated with dead cgroups during migration Documentation: cgroup v2: Trivial heading correction. cgroup: implement cgroup_subsys->implicit_on_dfl cgroup: use css_set->mg_dst_cgrp for the migration target cgroup cgroup: make cgroup[_taskset]_migrate() take cgroup_root instead of cgroup cgroup: move migration destination verification out of cgroup_migrate_prepare_dst() cgroup: fix incorrect destination cgroup in cgroup_update_dfl_csses() cgroup: Trivial correction to reflect controller. cgroup: remove stale item in cgroup-v1 document INDEX file. cgroup: update css iteration in cgroup_update_dfl_csses() cgroup: allocate 2x cgrp_cset_links when setting up a new root cgroup: make cgroup_calc_subtree_ss_mask() take @this_ss_mask cgroup: reimplement rebind_subsystems() using cgroup_apply_control() and friends cgroup: use cgroup_apply_enable_control() in cgroup creation path cgroup: combine cgroup_mutex locking and offline css draining cgroup: factor out cgroup_{apply|finalize}_control() from cgroup_subtree_control_write() cgroup: introduce cgroup_{save|propagate|restore}_control() cgroup: make cgroup_drain_offline() and cgroup_apply_control_{disable|enable}() recursive cgroup: factor out cgroup_apply_control_enable() from cgroup_subtree_control_write() ...
2016-03-18Merge branch 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wqLinus Torvalds
Pull workqueue updates from Tejun Heo: "Three trivial workqueue changes" * 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: Fix comment for work_on_cpu() sched/core: Get rid of 'cpu' argument in wq_worker_sleeping() workqueue: Replace usage of init_name with dev_set_name()
2016-03-18Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge second patch-bomb from Andrew Morton: - a couple of hotfixes - the rest of MM - a new timer slack control in procfs - a couple of procfs fixes - a few misc things - some printk tweaks - lib/ updates, notably to radix-tree. - add my and Nick Piggin's old userspace radix-tree test harness to tools/testing/radix-tree/. Matthew said it was a godsend during the radix-tree work he did. - a few code-size improvements, switching to __always_inline where gcc screwed up. - partially implement character sets in sscanf * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (118 commits) sscanf: implement basic character sets lib/bug.c: use common WARN helper param: convert some "on"/"off" users to strtobool lib: add "on"/"off" support to kstrtobool lib: update single-char callers of strtobool() lib: move strtobool() to kstrtobool() include/linux/unaligned: force inlining of byteswap operations include/uapi/linux/byteorder, swab: force inlining of some byteswap operations include/asm-generic/atomic-long.h: force inlining of some atomic_long operations usb: common: convert to use match_string() helper ide: hpt366: convert to use match_string() helper ata: hpt366: convert to use match_string() helper power: ab8500: convert to use match_string() helper power: charger_manager: convert to use match_string() helper drm/edid: convert to use match_string() helper pinctrl: convert to use match_string() helper device property: convert to use match_string() helper lib/string: introduce match_string() helper radix-tree tests: add test for radix_tree_iter_next radix-tree tests: add regression3 test ...
2016-03-18tracing: Remove redundant reset per-CPU buff in irqsoff tracerDmitry Safonov
There is no reason to do it twice: from commit b6f11df26fdc28 ("trace: Call tracing_reset_online_cpus before tracer->init()") resetting of per-CPU buffers done before tracer->init() call. tracer->init() calls {irqs,preempt,preemptirqs}off_tracer_init() and it calls __irqsoff_tracer_init(), which resets per-CPU ringbuffer second time. It's slowpath, but anyway. Link: http://lkml.kernel.org/r/1445278226-16187-1-git-send-email-0x7f454c46@gmail.com Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-18tracing: Fix crash from reading trace_pipe with sendfileSteven Rostedt (Red Hat)
If tracing contains data and the trace_pipe file is read with sendfile(), then it can trigger a NULL pointer dereference and various BUG_ON within the VM code. There's a patch to fix this in the splice_to_pipe() code, but it's also a good idea to not let that happen from trace_pipe either. Link: http://lkml.kernel.org/r/1457641146-9068-1-git-send-email-rabin@rab.in Cc: stable@vger.kernel.org # 2.6.30+ Reported-by: Rabin Vincent <rabin.vincent@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-18tracing: Have preempt(irqs)off trace preempt disabled functionsSteven Rostedt (Red Hat)
Joel Fernandes reported that the function tracing of preempt disabled sections was not being reported when running either the preemptirqsoff or preemptoff tracers. This was due to the fact that the function tracer callback for those tracers checked if irqs were disabled before tracing. But this fails when we want to trace preempt off locations as well. Joel explained that he wanted to see funcitons where interrupts are enabled but preemption was disabled. The expected output he wanted: <...>-2265 1d.h1 3419us : preempt_count_sub <-irq_exit <...>-2265 1d..1 3419us : __do_softirq <-irq_exit <...>-2265 1d..1 3419us : msecs_to_jiffies <-__do_softirq <...>-2265 1d..1 3420us : irqtime_account_irq <-__do_softirq <...>-2265 1d..1 3420us : __local_bh_disable_ip <-__do_softirq <...>-2265 1..s1 3421us : run_timer_softirq <-__do_softirq <...>-2265 1..s1 3421us : hrtimer_run_pending <-run_timer_softirq <...>-2265 1..s1 3421us : _raw_spin_lock_irq <-run_timer_softirq <...>-2265 1d.s1 3422us : preempt_count_add <-_raw_spin_lock_irq <...>-2265 1d.s2 3422us : _raw_spin_unlock_irq <-run_timer_softirq <...>-2265 1..s2 3422us : preempt_count_sub <-_raw_spin_unlock_irq <...>-2265 1..s1 3423us : rcu_bh_qs <-__do_softirq <...>-2265 1d.s1 3423us : irqtime_account_irq <-__do_softirq <...>-2265 1d.s1 3423us : __local_bh_enable <-__do_softirq There's a comment saying that the irq disabled check is because there's a possible race that tracing_cpu may be set when the function is executed. But I don't remember that race. For now, I added a check for preemption being enabled too to not record the function, as there would be no race if that was the case. I need to re-investigate this, as I'm now thinking that the tracing_cpu will always be correct. But no harm in keeping the check for now, except for the slight performance hit. Link: http://lkml.kernel.org/r/1457770386-88717-1-git-send-email-agnel.joel@gmail.com Fixes: 5e6d2b9cfa3a "tracing: Use one prologue for the preempt irqs off tracer function tracers" Cc: stable@vget.kernel.org # 2.6.37+ Reported-by: Joel Fernandes <agnel.joel@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-18tracing: Fix return while holding a lock in register_tracer()Chunyu Hu
commit d39cdd2036a6 ("tracing: Make tracer_flags use the right set_flag callback") introduces a potential mutex deadlock issue, as it forgets to free the mutex when allocaing the tracer_flags gets fail. The issue was found by Dan Carpenter through Smatch static code check tool. Link: http://lkml.kernel.org/r/1457958941-30265-1-git-send-email-chuhu@redhat.com Fixes: d39cdd2036a6 ("tracing: Make tracer_flags use the right set_flag callback") Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Chunyu Hu <chuhu@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-18ftrace: Use kasprintf() in ftrace_profile_tracefs()Geliang Tang
Use kasprintf() instead of kmalloc() and snprintf(). Link: http://lkml.kernel.org/r/135a7bc36e51fd9eaa57124dd2140285b771f738.1458050835.git.geliangtang@163.com Acked-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Geliang Tang <geliangtang@163.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-18ftrace: Update dynamic ftrace calls only if necessaryJiri Olsa
Currently dynamic ftrace calls are updated any time the ftrace_ops is un/registered. If we do this update only when it's needed, we save lot of time for perf system wide ftrace function sampling/counting. The reason is that for system wide sampling/counting, perf creates event for each cpu in the system. Each event then registers separate copy of ftrace_ops, which ends up in FTRACE_UPDATE_CALLS updates. On servers with many cpus that means serious stall (240 cpus server): Counting: # time ./perf stat -e ftrace:function -a sleep 1 Performance counter stats for 'system wide': 370,663 ftrace:function 1.401427505 seconds time elapsed real 3m51.743s user 0m0.023s sys 3m48.569s Sampling: # time ./perf record -e ftrace:function -a sleep 1 [ perf record: Woken up 0 times to write data ] Warning: Processed 141200 events and lost 5 chunks! [ perf record: Captured and wrote 10.703 MB perf.data (135950 samples) ] real 2m31.429s user 0m0.213s sys 2m29.494s There's no reason to do the FTRACE_UPDATE_CALLS update for each event in perf case, because all the ftrace_ops always share the same filter, so the updated calls are always the same. It's required that only first ftrace_ops registration does the FTRACE_UPDATE_CALLS update (also sometimes the second if the first one used the trampoline), but the rest can be only cheaply linked into the ftrace_ops list. Counting: # time ./perf stat -e ftrace:function -a sleep 1 Performance counter stats for 'system wide': 398,571 ftrace:function 1.377503733 seconds time elapsed real 0m2.787s user 0m0.005s sys 0m1.883s Sampling: # time ./perf record -e ftrace:function -a sleep 1 [ perf record: Woken up 0 times to write data ] Warning: Processed 261730 events and lost 9 chunks! [ perf record: Captured and wrote 19.907 MB perf.data (256293 samples) ] real 1m31.948s user 0m0.309s sys 1m32.051s Link: http://lkml.kernel.org/r/1458138873-1553-6-git-send-email-jolsa@kernel.org Acked-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-18ftrace: Make ftrace_hash_rec_enable return update boolJiri Olsa
Change __ftrace_hash_rec_update to return true in case we need to update dynamic ftrace call records. It return false in case no update is needed. Link: http://lkml.kernel.org/r/1458138873-1553-5-git-send-email-jolsa@kernel.org Acked-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-03-17Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching Pull livepatching update from Jiri Kosina: - cleanup of module notifiers; this depends on a module.c cleanup which has been acked by Rusty; from Jessica Yu - small assorted fixes and MAINTAINERS update * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching: livepatch/module: remove livepatch module notifier modules: split part of complete_formation() into prepare_coming_module() livepatch: Update maintainers livepatch: Fix the error message about unresolvable ambiguity klp: remove CONFIG_LIVEPATCH dependency from klp headers klp: remove superfluous errors in asm/livepatch.h