From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752853Ab2H1Oik (ORCPT ); Tue, 28 Aug 2012 10:38:40 -0400 Received: from mail.ispras.ru ([83.149.199.43]:47664 "EHLO mail.ispras.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751807Ab2H1Oij (ORCPT ); Tue, 28 Aug 2012 10:38:39 -0400 From: Alexey Khoroshilov To: "James E.J. Bottomley" Cc: Alexey Khoroshilov , linux-scsi@vger.kernel.org, Nagalakshmi Nandigama , Sreekanth.Reddy@lsi.com, linux-kernel@vger.kernel.org, ldv-project@ispras.ru Subject: [PATCH v2] [SCSI] mpt2sas: fix double mutex lock in NON_BLOCKING state Date: Tue, 28 Aug 2012 18:38:02 +0400 Message-Id: <1346164683-9315-1-git-send-email-khoroshilov@ispras.ru> X-Mailer: git-send-email 1.7.9.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If state is NON_BLOCKING and mutex_trylock is succeed, the control flow goes to mutex_lock_interruptible() that is a deadlock. The previous version of the patch becomes obsolete after code movement in commit 913809f6. Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by: Alexey Khoroshilov --- drivers/scsi/mpt2sas/mpt2sas_ctl.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/mpt2sas/mpt2sas_ctl.c b/drivers/scsi/mpt2sas/mpt2sas_ctl.c index 49bdd2d..d29ea56 100644 --- a/drivers/scsi/mpt2sas/mpt2sas_ctl.c +++ b/drivers/scsi/mpt2sas/mpt2sas_ctl.c @@ -2181,8 +2181,10 @@ _ctl_ioctl_main(struct file *file, unsigned int cmd, void __user *arg, return -EAGAIN; state = (file->f_flags & O_NONBLOCK) ? NON_BLOCKING : BLOCKING; - if (state == NON_BLOCKING && !mutex_trylock(&ioc->ctl_cmds.mutex)) - return -EAGAIN; + if (state == NON_BLOCKING) { + if (!mutex_trylock(&ioc->ctl_cmds.mutex)) + return -EAGAIN; + } else if (mutex_lock_interruptible(&ioc->ctl_cmds.mutex)) return -ERESTARTSYS; -- 1.7.9.5