[PATCH 09/11] net: Clean up sk_wait_event() vs might_sleep()

From: Peter Zijlstra <peterz@infradead.org>
To: mingo@kernel.org, oleg@redhat.com, torvalds@linux-foundation.org
Cc: tglx@linutronix.de, ilya.dryomov@inktank.com,
	umgwanakikbuti@gmail.com, linux-kernel@vger.kernel.org,
	Peter Zijlstra <peterz@infradead.org>,
	David Miller <davem@davemloft.net>
Subject: [PATCH 09/11] net: Clean up sk_wait_event() vs might_sleep()
Date: Wed, 24 Sep 2014 10:18:54 +0200	[thread overview]
Message-ID: <20140924082242.524407432@infradead.org> (raw)
In-Reply-To: 20140924081845.572814794@infradead.org

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WARNING: CPU: 1 PID: 1744 at kernel/sched/core.c:7104 __might_sleep+0x58/0x90()
do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff81070e10>] prepare_to_wait+0x50 /0xa0

 [<ffffffff8105bc38>] __might_sleep+0x58/0x90
 [<ffffffff8148c671>] lock_sock_nested+0x31/0xb0
 [<ffffffff81498aaa>] sk_stream_wait_memory+0x18a/0x2d0

Which is a false positive because sk_wait_event() will already have
TASK_RUNNING at that point if it would've gone through
schedule_timeout().

So annotate with fixup_sleep(); which goes away on !DEBUG builds.

Cc: netdev@vger.kernel.org
Cc: David Miller <davem@davemloft.net>
Reported-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 include/net/sock.h |    1 +
 1 file changed, 1 insertion(+)

--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -902,6 +902,7 @@ static inline void sock_rps_reset_rxhash
 		if (!__rc) {						\
 			*(__timeo) = schedule_timeout(*(__timeo));	\
 		}							\
+		fixup_sleep();						\
 		lock_sock(__sk);					\
 		__rc = __condition;					\
 		__rc;							\


