6.6-stable review patch. If anyone has any objections, please let me know.
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From: Namhyung Kim namhyung@kernel.org
[ Upstream commit fe826cc2654e8561b64246325e6a51b62bf2488c ]
Commit 558abc7e3f89 ("perf: Fix event_function_call() locking") lost IRQ disabling by mistake.
Fixes: 558abc7e3f89 ("perf: Fix event_function_call() locking") Reported-by: Pengfei Xu pengfei.xu@intel.com Reported-by: Naresh Kamboju naresh.kamboju@linaro.org Tested-by: Pengfei Xu pengfei.xu@intel.com Signed-off-by: Namhyung Kim namhyung@kernel.org Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/events/core.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c index 18eab7f50ecce..0ff381fa2f588 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -263,8 +263,8 @@ static int event_function(void *info) static void event_function_call(struct perf_event *event, event_f func, void *data) { struct perf_event_context *ctx = event->ctx; - struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */ + struct perf_cpu_context *cpuctx; struct event_function_struct efs = { .event = event, .func = func, @@ -292,22 +292,25 @@ static void event_function_call(struct perf_event *event, event_f func, void *da if (!task_function_call(task, event_function, &efs)) return;
+ local_irq_disable(); + cpuctx = this_cpu_ptr(&perf_cpu_context); perf_ctx_lock(cpuctx, ctx); /* * Reload the task pointer, it might have been changed by * a concurrent perf_event_context_sched_out(). */ task = ctx->task; - if (task == TASK_TOMBSTONE) { - perf_ctx_unlock(cpuctx, ctx); - return; - } + if (task == TASK_TOMBSTONE) + goto unlock; if (ctx->is_active) { perf_ctx_unlock(cpuctx, ctx); + local_irq_enable(); goto again; } func(event, NULL, ctx, data); +unlock: perf_ctx_unlock(cpuctx, ctx); + local_irq_enable(); }
/*