From: Peter Zijlstra <peterz@infradead.org> To: Oleg Nesterov <oleg@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com>, Ingo Molnar <mingo@redhat.com>, Arnaldo Carvalho de Melo <acme@kernel.org>, Alexander Shishkin <alexander.shishkin@linux.intel.com>, LKML <linux-kernel@vger.kernel.org>, Mathieu Desnoyers <mathieu.desnoyers@efficios.com>, syzkaller <syzkaller@googlegroups.com> Subject: Re: perf: use-after-free in perf_release Date: Tue, 14 Mar 2017 16:59:49 +0100 [thread overview] Message-ID: <20170314155949.GE32474@worktop> (raw) In-Reply-To: <20170314152625.GP5680@worktop> 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)
next prev parent reply other threads:[~2017-03-14 17:37 UTC|newest] Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-03-06 9:57 Dmitry Vyukov 2017-03-06 12:13 ` Peter Zijlstra 2017-03-06 12:17 ` Dmitry Vyukov 2017-03-06 12:23 ` Peter Zijlstra 2017-03-06 12:27 ` Dmitry Vyukov 2017-03-06 12:47 ` Peter Zijlstra 2017-03-06 13:14 ` Peter Zijlstra 2017-03-06 13:34 ` Dmitry Vyukov 2017-03-07 9:08 ` Peter Zijlstra 2017-03-07 9:26 ` Dmitry Vyukov 2017-03-07 9:37 ` Peter Zijlstra 2017-03-07 9:43 ` Dmitry Vyukov 2017-03-07 10:00 ` Peter Zijlstra 2017-03-07 13:16 ` Peter Zijlstra 2017-03-07 13:27 ` Peter Zijlstra 2017-03-07 14:04 ` Oleg Nesterov 2017-03-07 14:17 ` Dmitry Vyukov 2017-03-07 16:51 ` Oleg Nesterov 2017-03-07 17:29 ` Peter Zijlstra 2017-03-14 12:55 ` Peter Zijlstra 2017-03-14 13:24 ` Oleg Nesterov 2017-03-14 13:47 ` Peter Zijlstra 2017-03-14 14:03 ` Oleg Nesterov 2017-03-14 14:07 ` Peter Zijlstra 2017-03-14 14:30 ` Oleg Nesterov 2017-03-14 15:02 ` Peter Zijlstra 2017-03-14 15:07 ` Peter Zijlstra 2017-03-14 15:37 ` Oleg Nesterov 2017-03-14 15:46 ` Peter Zijlstra 2017-03-14 15:19 ` Oleg Nesterov 2017-03-14 15:26 ` Peter Zijlstra 2017-03-14 15:59 ` Peter Zijlstra [this message] 2017-03-15 16:43 ` Oleg Nesterov 2017-03-16 12:05 ` Peter Zijlstra 2017-03-16 13:57 ` Peter Zijlstra 2017-03-16 16:41 ` Oleg Nesterov 2017-03-16 12:47 [PATCH 0/4] perf patches Peter Zijlstra 2017-03-16 12:47 ` [PATCH 1/4] perf: Fix use-after-free in perf_release() Peter Zijlstra 2017-03-16 15:19 ` [tip:perf/urgent] perf/core: " tip-bot for Peter Zijlstra 2017-03-16 12:47 ` [PATCH 2/4] perf: Fix event inheritance on fork() Peter Zijlstra 2017-03-16 15:19 ` [tip:perf/urgent] perf/core: " tip-bot for Peter Zijlstra 2017-03-16 12:47 ` [PATCH 3/4] perf: Simplify perf_event_free_task() Peter Zijlstra 2017-03-16 15:20 ` [tip:perf/urgent] perf/core: " tip-bot for Peter Zijlstra 2017-03-16 12:47 ` [PATCH 4/4] perf: Better explain the inherit magic Peter Zijlstra 2017-03-16 15:21 ` [tip:perf/urgent] perf/core: " tip-bot for Peter Zijlstra 2017-03-16 13:20 ` [PATCH 0/4] perf patches Ingo Molnar
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