From: Alexey Khoroshilov <khoroshilov@ispras.ru>
To: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: Alexey Khoroshilov <khoroshilov@ispras.ru>,
linux-scsi@vger.kernel.org,
Nagalakshmi Nandigama <nagalakshmi.nandigama@lsi.com>,
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 [thread overview]
Message-ID: <1346164683-9315-1-git-send-email-khoroshilov@ispras.ru> (raw)
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 <khoroshilov@ispras.ru>
---
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
next reply other threads:[~2012-08-28 14:38 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-28 14:38 Alexey Khoroshilov [this message]
2012-08-29 10:18 ` [PATCH v2] [SCSI] mpt2sas: fix double mutex lock in NON_BLOCKING state Reddy, Sreekanth
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