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Groups > linux.kernel > #1600758
| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: perf: use-after-free in perf_release |
| Date | 2017-03-14 18:40 +0100 |
| Message-ID | <tkYAr-3tR-59@gated-at.bofh.it> (permalink) |
| References | (5 earlier) <tkVjc-1eJ-41@gated-at.bofh.it> <tkVMd-1qV-13@gated-at.bofh.it> <tkWff-1T2-5@gated-at.bofh.it> <tkWyB-20n-15@gated-at.bofh.it> <tkWyC-20n-23@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Tue, Mar 14, 2017 at 04:26:25PM +0100, Peter Zijlstra wrote: > A well.. I'll go do the 'trivial' patch then. A little like so; completely untested. --- kernel/events/core.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/kernel/events/core.c b/kernel/events/core.c index 110b38a58493..6576449b6029 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -10346,6 +10346,17 @@ void perf_event_free_task(struct task_struct *task) continue; mutex_lock(&ctx->mutex); + raw_spin_lock_irq(&ctx->lock); + /* + * Destroy the task <-> ctx relation and mark the context dead. + * + * This is important because even though the task hasn't been + * exposed yet the context has been (through child_list). + */ + RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL); + WRITE_ONCE(ctx->task, TASK_TOMBSTONE); + put_task_struct(task); /* cannot be last */ + raw_spin_unlock_irq(&ctx->lock); again: list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
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Re: perf: use-after-free in perf_release Peter Zijlstra <peterz@infradead.org> - 2017-03-14 14:00 +0100
Re: perf: use-after-free in perf_release Oleg Nesterov <oleg@redhat.com> - 2017-03-14 14:30 +0100
Re: perf: use-after-free in perf_release Peter Zijlstra <peterz@infradead.org> - 2017-03-14 14:50 +0100
Re: perf: use-after-free in perf_release Oleg Nesterov <oleg@redhat.com> - 2017-03-14 15:10 +0100
Re: perf: use-after-free in perf_release Peter Zijlstra <peterz@infradead.org> - 2017-03-14 15:10 +0100
Re: perf: use-after-free in perf_release Oleg Nesterov <oleg@redhat.com> - 2017-03-14 15:40 +0100
Re: perf: use-after-free in perf_release Peter Zijlstra <peterz@infradead.org> - 2017-03-14 16:10 +0100
Re: perf: use-after-free in perf_release Peter Zijlstra <peterz@infradead.org> - 2017-03-14 16:10 +0100
Re: perf: use-after-free in perf_release Oleg Nesterov <oleg@redhat.com> - 2017-03-14 16:40 +0100
Re: perf: use-after-free in perf_release Peter Zijlstra <peterz@infradead.org> - 2017-03-14 16:50 +0100
Re: perf: use-after-free in perf_release Peter Zijlstra <peterz@infradead.org> - 2017-03-14 16:30 +0100
Re: perf: use-after-free in perf_release Peter Zijlstra <peterz@infradead.org> - 2017-03-14 18:40 +0100
Re: perf: use-after-free in perf_release Oleg Nesterov <oleg@redhat.com> - 2017-03-15 17:50 +0100
Re: perf: use-after-free in perf_release Peter Zijlstra <peterz@infradead.org> - 2017-03-16 13:10 +0100
Re: perf: use-after-free in perf_release Peter Zijlstra <peterz@infradead.org> - 2017-03-16 15:00 +0100
Re: perf: use-after-free in perf_release Oleg Nesterov <oleg@redhat.com> - 2017-03-16 17:50 +0100
Re: perf: use-after-free in perf_release Oleg Nesterov <oleg@redhat.com> - 2017-03-14 16:30 +0100
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