From: tip-bot for Bart Van Assche <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: hpa@zytor.com, tglx@linutronix.de, linux-kernel@vger.kernel.org,
torvalds@linux-foundation.org, peterz@infradead.org,
mingo@kernel.org, cai@lca.pw, bvanassche@acm.org, tj@kernel.org
Subject: [tip:locking/urgent] workqueue: Only unregister a registered lockdep key
Date: Thu, 21 Mar 2019 04:04:05 -0700 [thread overview]
Message-ID: <tip-82efcab3b9f3ef59e9713237c6e3c05c3a95c1ae@git.kernel.org> (raw)
In-Reply-To: <20190311230255.176081-1-bvanassche@acm.org>
Commit-ID: 82efcab3b9f3ef59e9713237c6e3c05c3a95c1ae
Gitweb: https://git.kernel.org/tip/82efcab3b9f3ef59e9713237c6e3c05c3a95c1ae
Author: Bart Van Assche <bvanassche@acm.org>
AuthorDate: Mon, 11 Mar 2019 16:02:55 -0700
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Thu, 21 Mar 2019 12:00:18 +0100
workqueue: Only unregister a registered lockdep key
The recent change to prevent use after free and a memory leak introduced an
unconditional call to wq_unregister_lockdep() in the error handling
path. If the lockdep key had not been registered yet, then the lockdep core
emits a warning.
Only call wq_unregister_lockdep() if wq_register_lockdep() has been
called first.
Fixes: 009bb421b6ce ("workqueue, lockdep: Fix an alloc_workqueue() error path")
Reported-by: syzbot+be0c198232f86389c3dd@syzkaller.appspotmail.com
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Qian Cai <cai@lca.pw>
Link: https://lkml.kernel.org/r/20190311230255.176081-1-bvanassche@acm.org
---
kernel/workqueue.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 4026d1871407..ddee541ea97a 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -4266,7 +4266,7 @@ struct workqueue_struct *alloc_workqueue(const char *fmt,
INIT_LIST_HEAD(&wq->list);
if (alloc_and_link_pwqs(wq) < 0)
- goto err_free_wq;
+ goto err_unreg_lockdep;
if (wq_online && init_rescuer(wq) < 0)
goto err_destroy;
@@ -4292,9 +4292,10 @@ struct workqueue_struct *alloc_workqueue(const char *fmt,
return wq;
-err_free_wq:
+err_unreg_lockdep:
wq_unregister_lockdep(wq);
wq_free_lockdep(wq);
+err_free_wq:
free_workqueue_attrs(wq->unbound_attrs);
kfree(wq);
return NULL;
prev parent reply other threads:[~2019-03-21 11:04 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-11 23:02 [PATCH] kernel/workqueue: Only unregister a lockdep key if it has been registered first Bart Van Assche
2019-03-21 11:04 ` tip-bot for Bart Van Assche [this message]
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