From: Peter Zijlstra <peterz@infradead.org> mainline inclusion from mainline-v7.0-rc2 commit c9bc1753b3cc41d0e01fbca7f035258b5f4db0ae category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13907 CVE: CVE-2026-23271 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ---------------------------------------------------------------------- Make sure that __perf_event_overflow() runs with IRQs disabled for all possible callchains. Specifically the software events can end up running it with only preemption disabled. This opens up a race vs perf_event_exit_event() and friends that will go and free various things the overflow path expects to be present, like the BPF program. Fixes: 592903cdcbf6 ("perf_counter: add an event_list") Reported-by: Simond Hu <cmdhh1767@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Simond Hu <cmdhh1767@gmail.com> Link: https://patch.msgid.link/20260224122909.GV1395416@noisy.programming.kicks-as... Signed-off-by: Luo Gengkun <luogengkun2@huawei.com> --- kernel/events/core.c | 42 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 41 insertions(+), 1 deletion(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index e5c2105625a2..1d3f8eed6d0d 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -9708,6 +9708,13 @@ int perf_event_overflow(struct perf_event *event, struct perf_sample_data *data, struct pt_regs *regs) { + /* + * Entry point from hardware PMI, interrupts should be disabled here. + * This serializes us against perf_event_remove_from_context() in + * things like perf_event_release_kernel(). + */ + lockdep_assert_irqs_disabled(); + return __perf_event_overflow(event, 1, data, regs); } @@ -9788,6 +9795,19 @@ static void perf_swevent_event(struct perf_event *event, u64 nr, { struct hw_perf_event *hwc = &event->hw; + /* + * This is: + * - software preempt + * - tracepoint preempt + * - tp_target_task irq (ctx->lock) + * - uprobes preempt/irq + * - kprobes preempt/irq + * - hw_breakpoint irq + * + * Any of these are sufficient to hold off RCU and thus ensure @event + * exists. + */ + lockdep_assert_preemption_disabled(); local64_add(nr, &event->count); if (!regs) @@ -9796,6 +9816,16 @@ static void perf_swevent_event(struct perf_event *event, u64 nr, if (!is_sampling_event(event)) return; + /* + * Serialize against event_function_call() IPIs like normal overflow + * event handling. Specifically, must not allow + * perf_event_release_kernel() -> perf_remove_from_context() to make + * progress and 'release' the event from under us. + */ + guard(irqsave)(); + if (event->state != PERF_EVENT_STATE_ACTIVE) + return; + if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) { data->period = nr; return perf_swevent_overflow(event, 1, data, regs); @@ -10299,6 +10329,11 @@ void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size, struct perf_sample_data data; struct perf_event *event; + /* + * Per being a tracepoint, this runs with preemption disabled. + */ + lockdep_assert_preemption_disabled(); + struct perf_raw_record raw = { .frag = { .size = entry_size, @@ -10712,6 +10747,11 @@ void perf_bp_event(struct perf_event *bp, void *data) struct perf_sample_data sample; struct pt_regs *regs = data; + /* + * Exception context, will have interrupts disabled. + */ + lockdep_assert_irqs_disabled(); + perf_sample_data_init(&sample, bp->attr.bp_addr, 0); if (!bp->hw.state && !perf_exclude_event(bp, regs)) @@ -11164,7 +11204,7 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) if (regs && !perf_exclude_event(event, regs)) { if (!(event->attr.exclude_idle && is_idle_task(current))) - if (__perf_event_overflow(event, 1, &data, regs)) + if (perf_event_overflow(event, &data, regs)) ret = HRTIMER_NORESTART; } -- 2.34.1