James,

This patch seem to be fine. Please consider this patch as Acked-by: "Sreekanth 
Reddy" <sreekanth.re...@lsi.com>

Regards,
Sreekanth.

> -----Original Message-----
> From: Alexey Khoroshilov [mailto:khoroshi...@ispras.ru]
> Sent: Tuesday, August 28, 2012 8:08 PM
> To: James E.J. Bottomley
> Cc: Alexey Khoroshilov; linux-s...@vger.kernel.org; Nandigama,
> Nagalakshmi; Reddy, Sreekanth; linux-kernel@vger.kernel.org; ldv-
> proj...@ispras.ru
> Subject: [PATCH v2] [SCSI] mpt2sas: fix double mutex lock in
> NON_BLOCKING state
> 
> 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 <khoroshi...@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

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