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author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-01-30 14:02:32 +0100 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-01-30 14:02:32 +0100 |
commit | 27a96c4feb837093f6075bbd97c942260d26ef33 (patch) | |
tree | aa125b46d7101bf0c02361af6271fe2cb31e1fd3 | |
parent | Merge tag 'sched_urgent_for_v5.17_rc2_p2' of git://git.kernel.org/pub/scm/lin... (diff) | |
parent | perf/core: Fix cgroup event list management (diff) | |
download | linux-27a96c4feb837093f6075bbd97c942260d26ef33.tar.xz linux-27a96c4feb837093f6075bbd97c942260d26ef33.zip |
Merge tag 'perf_urgent_for_v5.17_rc2_p2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Borislav Petkov:
- Prevent accesses to the per-CPU cgroup context list from another CPU
except the one it belongs to, to avoid list corruption
- Make sure parent events are always woken up to avoid indefinite hangs
in the traced workload
* tag 'perf_urgent_for_v5.17_rc2_p2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/core: Fix cgroup event list management
perf: Always wake the parent event
-rw-r--r-- | kernel/events/core.c | 23 |
1 files changed, 19 insertions, 4 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 479c9e672ec4..76c754e45d01 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2462,7 +2462,11 @@ static void perf_remove_from_context(struct perf_event *event, unsigned long fla * event_function_call() user. */ raw_spin_lock_irq(&ctx->lock); - if (!ctx->is_active) { + /* + * Cgroup events are per-cpu events, and must IPI because of + * cgrp_cpuctx_list. + */ + if (!ctx->is_active && !is_cgroup_event(event)) { __perf_remove_from_context(event, __get_cpu_context(ctx), ctx, (void *)flags); raw_spin_unlock_irq(&ctx->lock); @@ -2895,11 +2899,14 @@ perf_install_in_context(struct perf_event_context *ctx, * perf_event_attr::disabled events will not run and can be initialized * without IPI. Except when this is the first event for the context, in * that case we need the magic of the IPI to set ctx->is_active. + * Similarly, cgroup events for the context also needs the IPI to + * manipulate the cgrp_cpuctx_list. * * The IOC_ENABLE that is sure to follow the creation of a disabled * event will issue the IPI and reprogram the hardware. */ - if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF && ctx->nr_events) { + if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF && + ctx->nr_events && !is_cgroup_event(event)) { raw_spin_lock_irq(&ctx->lock); if (ctx->task == TASK_TOMBSTONE) { raw_spin_unlock_irq(&ctx->lock); @@ -5985,6 +5992,8 @@ static void ring_buffer_attach(struct perf_event *event, struct perf_buffer *old_rb = NULL; unsigned long flags; + WARN_ON_ONCE(event->parent); + if (event->rb) { /* * Should be impossible, we set this when removing @@ -6042,6 +6051,9 @@ static void ring_buffer_wakeup(struct perf_event *event) { struct perf_buffer *rb; + if (event->parent) + event = event->parent; + rcu_read_lock(); rb = rcu_dereference(event->rb); if (rb) { @@ -6055,6 +6067,9 @@ struct perf_buffer *ring_buffer_get(struct perf_event *event) { struct perf_buffer *rb; + if (event->parent) + event = event->parent; + rcu_read_lock(); rb = rcu_dereference(event->rb); if (rb) { @@ -6763,7 +6778,7 @@ static unsigned long perf_prepare_sample_aux(struct perf_event *event, if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id())) goto out; - rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler); + rb = ring_buffer_get(sampler); if (!rb) goto out; @@ -6829,7 +6844,7 @@ static void perf_aux_sample_output(struct perf_event *event, if (WARN_ON_ONCE(!sampler || !data->aux_size)) return; - rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler); + rb = ring_buffer_get(sampler); if (!rb) return; |