From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> mainline inclusion from mainline-v6.11-rc1 commit c5d93d23a26012a98b77f9e354ab9b3afd420059 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/20234 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ---------------------------------------------------------------------- A signal is delivered by raising irq_work() which works from any context including NMI. irq_work() can be delayed if the architecture does not provide an interrupt vector. In order not to lose a signal, the signal is injected via task_work during event_sched_out(). Instead going via irq_work, the signal could be added directly via task_work. The signal is sent to current and can be enqueued on its return path to userland. Queue signal via task_work and consider possible NMI context. Remove perf_event::pending_sigtrap and and use perf_event::pending_work instead. Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Marco Elver <elver@google.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Link: https://lore.kernel.org/r/20240704170424.1466941-4-bigeasy@linutronix.de Conflicts: [Fix simple ctx diff.] Signed-off-by: Luo Gengkun <luogengkun2@huawei.com> --- include/linux/perf_event.h | 3 +-- kernel/events/core.c | 33 +++++++++++---------------------- 2 files changed, 12 insertions(+), 24 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index f784fe5136d5..b99256b73ce0 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -803,7 +803,6 @@ struct perf_event { unsigned int pending_wakeup; unsigned int pending_kill; unsigned int pending_disable; - unsigned int pending_sigtrap; unsigned long pending_addr; /* SIGTRAP */ struct irq_work pending_irq; struct callback_head pending_task; @@ -988,7 +987,7 @@ struct perf_event_context { struct rcu_head rcu_head; /* - * Sum (event->pending_sigtrap + event->pending_work) + * Sum (event->pending_work + event->pending_work) * * The SIGTRAP is targeted at ctx->task, as such it won't do changing * that until the signal is delivered. diff --git a/kernel/events/core.c b/kernel/events/core.c index 6e78b7af0062..4612ab9ef94e 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2307,18 +2307,6 @@ event_sched_out(struct perf_event *event, struct perf_event_context *ctx) state = PERF_EVENT_STATE_OFF; } - if (event->pending_sigtrap) { - event->pending_sigtrap = 0; - if (state != PERF_EVENT_STATE_OFF && - !event->pending_work && - !task_work_add(current, &event->pending_task, TWA_RESUME)) { - event->pending_work = 1; - WARN_ON_ONCE(!atomic_long_inc_not_zero(&event->refcount)); - } else { - local_dec(&event->ctx->nr_pending); - } - } - perf_event_set_state(event, state); if (!is_software_event(event)) @@ -6824,11 +6812,6 @@ static void __perf_pending_irq(struct perf_event *event) * Yay, we hit home and are in the context of the event. */ if (cpu == smp_processor_id()) { - if (event->pending_sigtrap) { - event->pending_sigtrap = 0; - perf_sigtrap(event); - local_dec(&event->ctx->nr_pending); - } if (event->pending_disable) { event->pending_disable = 0; perf_event_disable_local(event); @@ -9723,21 +9706,27 @@ static int __perf_event_overflow(struct perf_event *event, */ bool valid_sample = sample_is_allowed(event, regs); unsigned int pending_id = 1; + enum task_work_notify_mode notify_mode; if (regs) pending_id = hash32_ptr((void *)instruction_pointer(regs)) ?: 1; - if (!event->pending_sigtrap) { - event->pending_sigtrap = pending_id; + + notify_mode = in_nmi() ? TWA_NMI_CURRENT : TWA_RESUME; + + if (!event->pending_work && + !task_work_add(current, &event->pending_task, notify_mode)) { + event->pending_work = pending_id; local_inc(&event->ctx->nr_pending); + WARN_ON_ONCE(!atomic_long_inc_not_zero(&event->refcount)); event->pending_addr = 0; if (valid_sample && (data->sample_flags & PERF_SAMPLE_ADDR)) event->pending_addr = data->addr; - irq_work_queue(&event->pending_irq); + } else if (event->attr.exclude_kernel && valid_sample) { /* * Should not be able to return to user space without - * consuming pending_sigtrap; with exceptions: + * consuming pending_work; with exceptions: * * 1. Where !exclude_kernel, events can overflow again * in the kernel without returning to user space. @@ -9747,7 +9736,7 @@ static int __perf_event_overflow(struct perf_event *event, * To approximate progress (with false negatives), * check 32-bit hash of the current IP. */ - WARN_ON_ONCE(event->pending_sigtrap != pending_id); + WARN_ON_ONCE(event->pending_work != pending_id); } } -- 2.34.1