Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755033Ab3CKV0e (ORCPT ); Mon, 11 Mar 2013 17:26:34 -0400 Received: from mailout01.c08.mtsvc.net ([205.186.168.189]:33431 "EHLO mailout01.c08.mtsvc.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754833Ab3CKVPY (ORCPT ); Mon, 11 Mar 2013 17:15:24 -0400 From: Peter Hurley To: Greg Kroah-Hartman , Jiri Slaby Cc: Sasha Levin , Dave Jones , Sebastian Andrzej Siewior , Shawn Guo , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Peter Hurley Subject: [PATCH v5 27/44] tty: Drop lock contention stat from ldsem trylocks Date: Mon, 11 Mar 2013 16:44:47 -0400 Message-Id: <1363034704-28036-28-git-send-email-peter@hurleysoftware.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1363034704-28036-1-git-send-email-peter@hurleysoftware.com> References: <1361390599-15195-1-git-send-email-peter@hurleysoftware.com> <1363034704-28036-1-git-send-email-peter@hurleysoftware.com> X-Authenticated-User: 125194 peter@hurleysoftware.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3020 Lines: 73 When lockdep is notified of lock contention, lockdep expects its internal state to indicate the lock is held. Since trylocks cannot reflect this state unless the lock is actually acquired, contention stats cannot be collected for trylocks. Fixes: [ 1473.912280] ================================= [ 1473.913180] [ BUG: bad contention detected! ] [ 1473.914071] 3.8.0-next-20130220-sasha-00038-g1ad55df-dirty #8 Tainted: G W [ 1473.915684] --------------------------------- [ 1473.916549] kworker/1:1/361 is trying to contend lock (&tty->ldisc_sem) at: [ 1473.918031] [] tty_ldisc_ref+0x1f/0x60 [ 1473.919060] but there are no locks held! [ 1473.919813] [ 1473.919813] other info that might help us debug this: [ 1473.920044] 2 locks held by kworker/1:1/361: [ 1473.920044] #0: (events){.+.+.+}, at: [] process_one_work+0x228/0x6a0 [ 1473.920044] #1: ((&buf->work)){+.+...}, at: [] process_one_work+0x228/0x6a0 [ 1473.920044] [ 1473.920044] stack backtrace: [ 1473.920044] Pid: 361, comm: kworker/1:1 Tainted: G W 3.8.0-next-20130220-sasha-00038-g1ad55df-dirty #8 [ 1473.920044] Call Trace: [ 1473.920044] [] ? tty_ldisc_ref+0x1f/0x60 [ 1473.920044] [] print_lock_contention_bug+0xf6/0x110 [ 1473.920044] [] lock_contended+0x213/0x4e0 [ 1473.920044] [] ldsem_down_read_trylock+0xb1/0xc0 [ 1473.920044] [] tty_ldisc_ref+0x1f/0x60 [ 1473.920044] [] flush_to_ldisc+0x37/0x1a0 [ 1473.920044] [] process_one_work+0x366/0x6a0 [ 1473.920044] [] ? process_one_work+0x228/0x6a0 [ 1473.920044] [] worker_thread+0x238/0x370 [ 1473.920044] [] ? rescuer_thread+0x310/0x310 [ 1473.920044] [] kthread+0xe3/0xf0 [ 1473.920044] [] ? flush_kthread_work+0x1f0/0x1f0 [ 1473.920044] [] ret_from_fork+0x7c/0xb0 [ 1473.920044] [] ? flush_kthread_work+0x1f0/0x1f0 Reported-by: Sasha Levin Signed-off-by: Peter Hurley --- drivers/tty/tty_ldsem.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/drivers/tty/tty_ldsem.c b/drivers/tty/tty_ldsem.c index 0ab5b09..c162295 100644 --- a/drivers/tty/tty_ldsem.c +++ b/drivers/tty/tty_ldsem.c @@ -419,7 +419,6 @@ int ldsem_down_read_trylock(struct ld_semaphore *sem) return 1; } } - lock_stat(sem, contended); return 0; } @@ -453,9 +452,7 @@ int ldsem_down_write_trylock(struct ld_semaphore *sem) lock_stat(sem, acquired); return 1; } - raw_spin_unlock_irq(&sem->wait_lock); - lock_stat(sem, contended); return 0; } -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/