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From: Peter Zijlstra <peterz@infradead.org>
To: mingo@kernel.org
Cc: linux-kernel@vger.kernel.org, acme@kernel.org,
	mathieu.desnoyers@efficios.com,
	alexander.shishkin@linux.intel.com, dvyukov@google.com,
	fweisbec@gmail.com, oleg@redhat.com, peterz@infradead.org,
	stable@vger.kernel.org
Subject: [PATCH 2/4] perf: Fix event inheritance on fork()
Date: Thu, 16 Mar 2017 13:47:49 +0100
Message-ID: <20170316125823.190342547@infradead.org> (raw)
In-Reply-To: <20170316124747.804596354@infradead.org>


[-- Attachment #0: peterz-perf-fix-perf_event_init_context.patch --]
[-- Type: text/plain, Size: 1556 bytes --]

While hunting for clues to a use-after-free, Oleg spotted that
perf_event_init_context() can loose an error value with the result
that fork() can succeed even though we did not fully inherit the perf
event context.

Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: stable@vger.kernel.org
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Spotted-by: Oleg Nesterov <oleg@redhat.com>
Fixes: 889ff0150661 ("perf/core: Split context's event group list into pinned and non-pinned lists")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 kernel/events/core.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10820,7 +10819,7 @@ static int perf_event_init_context(struc
 		ret = inherit_task_group(event, parent, parent_ctx,
 					 child, ctxn, &inherited_all);
 		if (ret)
-			break;
+			goto out_unlock;
 	}
 
 	/*
@@ -10836,7 +10835,7 @@ static int perf_event_init_context(struc
 		ret = inherit_task_group(event, parent, parent_ctx,
 					 child, ctxn, &inherited_all);
 		if (ret)
-			break;
+			goto out_unlock;
 	}
 
 	raw_spin_lock_irqsave(&parent_ctx->lock, flags);
@@ -10864,6 +10863,7 @@ static int perf_event_init_context(struc
 	}
 
 	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
+out_unlock:
 	mutex_unlock(&parent_ctx->mutex);
 
 	perf_unpin_context(parent_ctx);

  parent reply index

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
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 ` Peter Zijlstra [this message]
2017-03-16 15:19   ` [tip:perf/urgent] perf/core: Fix event inheritance on fork() 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
  -- strict thread matches above, loose matches on Subject: below --
2017-03-06  9:57 perf: use-after-free in perf_release 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
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

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