From: Oleg Nesterov <oleg@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>, Al Viro <viro@zeniv.linux.org.uk>
Cc: Dave Jones <davej@redhat.com>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
rostedt <rostedt@goodmis.org>, dhowells <dhowells@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH 3/4] task_work: revert d35abdb2 "hold task_lock around checks in keyctl"
Date: Sun, 26 Aug 2012 21:12:14 +0200 [thread overview]
Message-ID: <20120826191214.GA4231@redhat.com> (raw)
In-Reply-To: <20120826191132.GA3743@redhat.com>
This reverts commit d35abdb28824cf74f0a106a0f9c6f3ff700a35bf.
task_lock() was added to ensure exit_mm() and thus exit_task_work() is
not possible before task_work_add().
This is wrong, task_lock() must not be nested with write_lock(tasklist).
And this is no longer needed, task_work_add() fails if it is called
after exit_task_work().
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
security/keys/keyctl.c | 2 --
1 files changed, 0 insertions(+), 2 deletions(-)
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index 3364fbf..6cfc647 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -1486,7 +1486,6 @@ long keyctl_session_to_parent(void)
oldwork = NULL;
parent = me->real_parent;
- task_lock(parent);
/* the parent mustn't be init and mustn't be a kernel thread */
if (parent->pid <= 1 || !parent->mm)
goto unlock;
@@ -1530,7 +1529,6 @@ long keyctl_session_to_parent(void)
if (!ret)
newwork = NULL;
unlock:
- task_unlock(parent);
write_unlock_irq(&tasklist_lock);
rcu_read_unlock();
if (oldwork)
--
1.5.5.1
next prev parent reply other threads:[~2012-08-26 19:10 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-24 20:36 lockdep trace from posix timers Dave Jones
2012-07-27 16:20 ` Dave Jones
2012-08-16 12:54 ` Ming Lei
2012-08-16 14:03 ` Dave Jones
2012-08-16 18:07 ` Peter Zijlstra
2012-08-17 15:14 ` Oleg Nesterov
2012-08-17 15:17 ` Oleg Nesterov
2012-08-17 16:40 ` task_work_add() should not succeed unconditionally (Was: lockdep trace from posix timers) Oleg Nesterov
2012-08-20 7:15 ` lockdep trace from posix timers Peter Zijlstra
2012-08-20 11:44 ` Peter Zijlstra
2012-08-20 11:46 ` Peter Zijlstra
2012-08-20 11:50 ` Peter Zijlstra
2012-08-20 12:19 ` Steven Rostedt
2012-08-20 12:20 ` Peter Zijlstra
2012-08-20 14:59 ` Oleg Nesterov
2012-08-20 15:10 ` Peter Zijlstra
2012-08-20 15:27 ` Peter Zijlstra
2012-08-20 15:32 ` Oleg Nesterov
2012-08-20 15:46 ` Peter Zijlstra
2012-08-20 15:58 ` Oleg Nesterov
2012-08-20 16:03 ` Peter Zijlstra
2012-08-20 15:05 ` Oleg Nesterov
2012-08-20 15:12 ` Peter Zijlstra
2012-08-20 15:41 ` Oleg Nesterov
2012-08-20 15:56 ` Peter Zijlstra
2012-08-20 16:10 ` Oleg Nesterov
2012-08-20 16:19 ` Peter Zijlstra
2012-08-20 16:23 ` Oleg Nesterov
2012-08-21 18:27 ` Oleg Nesterov
2012-08-21 18:34 ` Oleg Nesterov
2012-08-24 18:56 ` Oleg Nesterov
2012-08-26 19:11 ` [PATCH 0/4] (Was: lockdep trace from posix timers) Oleg Nesterov
2012-08-26 19:12 ` [PATCH 1/4] task_work: make task_work_add() lockless Oleg Nesterov
2012-09-14 6:08 ` [tip:core/urgent] task_work: Make " tip-bot for Oleg Nesterov
2012-09-24 19:27 ` [PATCH 1/4] task_work: make " Geert Uytterhoeven
2012-09-24 20:37 ` Oleg Nesterov
2012-08-26 19:12 ` [PATCH 2/4] task_work: task_work_add() should not succeed after exit_task_work() Oleg Nesterov
2012-09-14 6:09 ` [tip:core/urgent] " tip-bot for Oleg Nesterov
2012-08-26 19:12 ` Oleg Nesterov [this message]
2012-09-14 6:10 ` [tip:core/urgent] task_work: Revert " hold task_lock around checks in keyctl" tip-bot for Oleg Nesterov
2012-08-26 19:12 ` [PATCH 4/4] task_work: simplify the usage in ptrace_notify() and get_signal_to_deliver() Oleg Nesterov
2012-09-14 6:11 ` [tip:core/urgent] task_work: Simplify " tip-bot for Oleg Nesterov
2012-09-06 18:01 ` [PATCH 0/4] (Was: lockdep trace from posix timers) Oleg Nesterov
2012-09-06 18:35 ` Peter Zijlstra
2012-09-07 13:13 ` Oleg Nesterov
2012-08-28 16:29 ` lockdep trace from posix timers Peter Zijlstra
2012-08-28 17:01 ` Oleg Nesterov
2012-08-28 17:12 ` Oleg Nesterov
2012-08-28 17:28 ` Peter Zijlstra
2012-08-29 15:25 ` Oleg Nesterov
2012-08-20 14:55 ` Oleg Nesterov
2012-08-20 15:43 ` Oleg Nesterov
2012-08-20 15:48 ` Peter Zijlstra
2012-08-20 15:58 ` Oleg Nesterov
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