user/sven/linux.git/kernel/events, branch v5.2

perf/x86: Disable extended registers for non-supported PMUs

2019-06-24T17:19:23Z

The perf fuzzer caused Skylake machine to crash: [ 9680.085831] Call Trace: [ 9680.088301] [ 9680.090363] perf_output_sample_regs+0x43/0xa0 [ 9680.094928] perf_output_sample+0x3aa/0x7a0 [ 9680.099181] perf_event_output_forward+0x53/0x80 [ 9680.103917] __perf_event_overflow+0x52/0xf0 [ 9680.108266] ? perf_trace_run_bpf_submit+0xc0/0xc0 [ 9680.113108] perf_swevent_hrtimer+0xe2/0x150 [ 9680.117475] ? check_preempt_wakeup+0x181/0x230 [ 9680.122091] ? check_preempt_curr+0x62/0x90 [ 9680.126361] ? ttwu_do_wakeup+0x19/0x140 [ 9680.130355] ? try_to_wake_up+0x54/0x460 [ 9680.134366] ? reweight_entity+0x15b/0x1a0 [ 9680.138559] ? __queue_work+0x103/0x3f0 [ 9680.142472] ? update_dl_rq_load_avg+0x1cd/0x270 [ 9680.147194] ? timerqueue_del+0x1e/0x40 [ 9680.151092] ? __remove_hrtimer+0x35/0x70 [ 9680.155191] __hrtimer_run_queues+0x100/0x280 [ 9680.159658] hrtimer_interrupt+0x100/0x220 [ 9680.163835] smp_apic_timer_interrupt+0x6a/0x140 [ 9680.168555] apic_timer_interrupt+0xf/0x20 [ 9680.172756] The XMM registers can only be collected by PEBS hardware events on the platforms with PEBS baseline support, e.g. Icelake, not software/probe events. Add capabilities flag PERF_PMU_CAP_EXTENDED_REGS to indicate the PMU which support extended registers. For X86, the extended registers are XMM registers. Add has_extended_regs() to check if extended registers are applied. The generic code define the mask of extended registers as 0 if arch headers haven't overridden it. Originally-by: Peter Zijlstra (Intel) Reported-by: Vince Weaver Signed-off-by: Kan Liang Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Fixes: 878068ea270e ("perf/x86: Support outputting XMM registers") Link: https://lkml.kernel.org/r/1559081314-9714-1-git-send-email-kan.liang@linux.intel.com Signed-off-by: Ingo Molnar

perf/ioctl: Add check for the sample_period value

2019-06-24T17:19:22Z

perf_event_open() limits the sample_period to 63 bits. See: 0819b2e30ccb ("perf: Limit perf_event_attr::sample_period to 63 bits") Make ioctl() consistent with it. Also on PowerPC, negative sample_period could cause a recursive PMIs leading to a hang (reported when running perf-fuzzer). Signed-off-by: Ravi Bangoria Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: acme@kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: maddy@linux.vnet.ibm.com Cc: mpe@ellerman.id.au Fixes: 0819b2e30ccb ("perf: Limit perf_event_attr::sample_period to 63 bits") Link: https://lkml.kernel.org/r/20190604042953.914-1-ravi.bangoria@linux.ibm.com Signed-off-by: Ingo Molnar

perf/core: Fix perf_sample_regs_user() mm check

2019-06-17T10:11:58Z

perf_sample_regs_user() uses 'current->mm' to test for the presence of userspace, but this is insufficient, consider use_mm(). A better test is: '!(current->flags & PF_KTHREAD)', exec() clears PF_KTHREAD after it sets the new ->mm but before it drops to userspace for the first time. Possibly obsoletes: bf05fc25f268 ("powerpc/perf: Fix oops when kthread execs user process") Reported-by: Ravi Bangoria Reported-by: Young Xiao <92siuyang@gmail.com> Signed-off-by: Peter Zijlstra (Intel) Acked-by: Will Deacon Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Linus Torvalds Cc: Michael Ellerman Cc: Naveen N. Rao Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Fixes: 4018994f3d87 ("perf: Add ability to attach user level registers dump to sample") Signed-off-by: Ingo Molnar

perf/ring-buffer: Use regular variables for nesting

2019-05-24T07:00:11Z

While the IRQ/NMI will nest, the nest-count will be invariant over the actual exception, since it will decrement equal to increment. This means we can -- carefully -- use a regular variable since the typical LOAD-STORE race doesn't exist (similar to preempt_count). This optimizes the ring-buffer for all LOAD-STORE architectures, since they need to use atomic ops to implement local_t. Suggested-by: Alexander Shishkin Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: acme@kernel.org Cc: mark.rutland@arm.com Cc: namhyung@kernel.org Cc: yabinc@google.com Link: http://lkml.kernel.org/r/20190517115418.481392777@infradead.org Signed-off-by: Ingo Molnar

perf/ring-buffer: Always use {READ,WRITE}_ONCE() for rb->user_page data

2019-05-24T07:00:11Z

We must use {READ,WRITE}_ONCE() on rb->user_page data such that concurrent usage will see whole values. A few key sites were missing this. Suggested-by: Yabin Cui Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: acme@kernel.org Cc: mark.rutland@arm.com Cc: namhyung@kernel.org Fixes: 7b732a750477 ("perf_counter: new output ABI - part 1") Link: http://lkml.kernel.org/r/20190517115418.394192145@infradead.org Signed-off-by: Ingo Molnar

perf/ring_buffer: Add ordering to rb->nest increment

2019-05-24T07:00:10Z

Similar to how decrementing rb->next too early can cause data_head to (temporarily) be observed to go backward, so too can this happen when we increment too late. This barrier() ensures the rb->head load happens after the increment, both the one in the 'goto again' path, as the one from perf_output_get_handle() -- albeit very unlikely to matter for the latter. Suggested-by: Yabin Cui Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: acme@kernel.org Cc: mark.rutland@arm.com Cc: namhyung@kernel.org Fixes: ef60777c9abd ("perf: Optimize the perf_output() path by removing IRQ-disables") Link: http://lkml.kernel.org/r/20190517115418.309516009@infradead.org Signed-off-by: Ingo Molnar

perf/ring_buffer: Fix exposing a temporarily decreased data_head

2019-05-24T07:00:10Z

In perf_output_put_handle(), an IRQ/NMI can happen in below location and write records to the same ring buffer: ... local_dec_and_test(&rb->nest) ... <-- an IRQ/NMI can happen here rb->user_page->data_head = head; ... In this case, a value A is written to data_head in the IRQ, then a value B is written to data_head after the IRQ. And A > B. As a result, data_head is temporarily decreased from A to B. And a reader may see data_head < data_tail if it read the buffer frequently enough, which creates unexpected behaviors. This can be fixed by moving dec(&rb->nest) to after updating data_head, which prevents the IRQ/NMI above from updating data_head. [ Split up by peterz. ] Signed-off-by: Yabin Cui Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: mark.rutland@arm.com Fixes: ef60777c9abd ("perf: Optimize the perf_output() path by removing IRQ-disables") Link: http://lkml.kernel.org/r/20190517115418.224478157@infradead.org Signed-off-by: Ingo Molnar

mm/mmu_notifier: use correct mmu_notifier events for each invalidation

2019-05-14T16:47:49Z

This updates each existing invalidation to use the correct mmu notifier event that represent what is happening to the CPU page table. See the patch which introduced the events to see the rational behind this. Link: http://lkml.kernel.org/r/20190326164747.24405-7-jglisse@redhat.com Signed-off-by: Jérôme Glisse Reviewed-by: Ralph Campbell Reviewed-by: Ira Weiny Cc: Christian König Cc: Joonas Lahtinen Cc: Jani Nikula Cc: Rodrigo Vivi Cc: Jan Kara Cc: Andrea Arcangeli Cc: Peter Xu Cc: Felix Kuehling Cc: Jason Gunthorpe Cc: Ross Zwisler Cc: Dan Williams Cc: Paolo Bonzini Cc: Radim Krcmar Cc: Michal Hocko Cc: Christian Koenig Cc: John Hubbard Cc: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/mmu_notifier: contextual information for event triggering invalidation

2019-05-14T16:47:49Z

CPU page table update can happens for many reasons, not only as a result of a syscall (munmap(), mprotect(), mremap(), madvise(), ...) but also as a result of kernel activities (memory compression, reclaim, migration, ...). Users of mmu notifier API track changes to the CPU page table and take specific action for them. While current API only provide range of virtual address affected by the change, not why the changes is happening. This patchset do the initial mechanical convertion of all the places that calls mmu_notifier_range_init to also provide the default MMU_NOTIFY_UNMAP event as well as the vma if it is know (most invalidation happens against a given vma). Passing down the vma allows the users of mmu notifier to inspect the new vma page protection. The MMU_NOTIFY_UNMAP is always the safe default as users of mmu notifier should assume that every for the range is going away when that event happens. A latter patch do convert mm call path to use a more appropriate events for each call. This is done as 2 patches so that no call site is forgotten especialy as it uses this following coccinelle patch: %<---------------------------------------------------------------------- @@ identifier I1, I2, I3, I4; @@ static inline void mmu_notifier_range_init(struct mmu_notifier_range *I1, +enum mmu_notifier_event event, +unsigned flags, +struct vm_area_struct *vma, struct mm_struct *I2, unsigned long I3, unsigned long I4) { ... } @@ @@ -#define mmu_notifier_range_init(range, mm, start, end) +#define mmu_notifier_range_init(range, event, flags, vma, mm, start, end) @@ expression E1, E3, E4; identifier I1; @@ <... mmu_notifier_range_init(E1, +MMU_NOTIFY_UNMAP, 0, I1, I1->vm_mm, E3, E4) ...> @@ expression E1, E2, E3, E4; identifier FN, VMA; @@ FN(..., struct vm_area_struct *VMA, ...) { <... mmu_notifier_range_init(E1, +MMU_NOTIFY_UNMAP, 0, VMA, E2, E3, E4) ...> } @@ expression E1, E2, E3, E4; identifier FN, VMA; @@ FN(...) { struct vm_area_struct *VMA; <... mmu_notifier_range_init(E1, +MMU_NOTIFY_UNMAP, 0, VMA, E2, E3, E4) ...> } @@ expression E1, E2, E3, E4; identifier FN; @@ FN(...) { <... mmu_notifier_range_init(E1, +MMU_NOTIFY_UNMAP, 0, NULL, E2, E3, E4) ...> } ---------------------------------------------------------------------->% Applied with: spatch --all-includes --sp-file mmu-notifier.spatch fs/proc/task_mmu.c --in-place spatch --sp-file mmu-notifier.spatch --dir kernel/events/ --in-place spatch --sp-file mmu-notifier.spatch --dir mm --in-place Link: http://lkml.kernel.org/r/20190326164747.24405-6-jglisse@redhat.com Signed-off-by: Jérôme Glisse Reviewed-by: Ralph Campbell Reviewed-by: Ira Weiny Cc: Christian König Cc: Joonas Lahtinen Cc: Jani Nikula Cc: Rodrigo Vivi Cc: Jan Kara Cc: Andrea Arcangeli Cc: Peter Xu Cc: Felix Kuehling Cc: Jason Gunthorpe Cc: Ross Zwisler Cc: Dan Williams Cc: Paolo Bonzini Cc: Radim Krcmar Cc: Michal Hocko Cc: Christian Koenig Cc: John Hubbard Cc: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge tag 'printk-for-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk

2019-05-07T16:18:12Z

Pull printk updates from Petr Mladek: - Allow state reset of printk_once() calls. - Prevent crashes when dereferencing invalid pointers in vsprintf(). Only the first byte is checked for simplicity. - Make vsprintf warnings consistent and inlined. - Treewide conversion of obsolete %pf, %pF to %ps, %pF printf modifiers. - Some clean up of vsprintf and test_printf code. * tag 'printk-for-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk: lib/vsprintf: Make function pointer_string static vsprintf: Limit the length of inlined error messages vsprintf: Avoid confusion between invalid address and value vsprintf: Prevent crash when dereferencing invalid pointers vsprintf: Consolidate handling of unknown pointer specifiers vsprintf: Factor out %pO handler as kobject_string() vsprintf: Factor out %pV handler as va_format() vsprintf: Factor out %p[iI] handler as ip_addr_string() vsprintf: Do not check address of well-known strings vsprintf: Consistent %pK handling for kptr_restrict == 0 vsprintf: Shuffle restricted_pointer() printk: Tie printk_once / printk_deferred_once into .data.once for reset treewide: Switch printk users from %pf and %pF to %ps and %pS, respectively lib/test_printf: Switch to bitmap_zalloc()