[PATCH 1/4] mvsas: bugfix for NULL pointer execption

[PATCH 1/4] mvsas: bugfix for NULL pointer execption

[Ying Chu]

>From 347191384292c6e9a9a572c657049bc11615fb82 Mon Sep 17 00:00:00 2001
From: Andy <ayan@marvell.com>
Date: Mon, 4 May 2009 23:29:26 +0800
Subject: [PATCH 1/4] mvsas: bug fix, null pointer may be used

Null pointer exception when mvi_dev is null.

Signed-off-by: Ying Chu <jasonchu@marvell.com>
Signed-off-by: Andy Yan <ayan@marvell.com>
Signed-off-by: Ke Wei <kewei@marvell.com>
---
 drivers/scsi/mvsas/mv_sas.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/mvsas/mv_sas.c b/drivers/scsi/mvsas/mv_sas.c
index d79ac17..318ec01 100644
--- a/drivers/scsi/mvsas/mv_sas.c
+++ b/drivers/scsi/mvsas/mv_sas.c
@@ -1873,11 +1873,11 @@ int mvs_slot_complete(struct mvs_info *mvi, u32 rx_desc, u32 flags)
 	}
 
 out:
-	if (mvi_dev)
+	if (mvi_dev) {
 		mvi_dev->runing_req--;
-	if (sas_protocol_ata(task->task_proto))
-		mvs_free_reg_set(mvi, mvi_dev);
-
+		if (sas_protocol_ata(task->task_proto))
+			mvs_free_reg_set(mvi, mvi_dev);
+	}
 	mvs_slot_task_free(mvi, task, slot, slot_idx);
 	sts = tstat->stat;
 
-- 
1.6.0.3

-- 
Regards,
Ying Chu

Re: [PATCH 1/4] mvsas: bugfix for NULL pointer execption

[James Bottomley]

On Fri, 2009-05-08 at 14:15 +0800, Ying Chu wrote:
> >From 347191384292c6e9a9a572c657049bc11615fb82 Mon Sep 17 00:00:00 2001
> From: Andy <ayan@marvell.com>
> Date: Mon, 4 May 2009 23:29:26 +0800
> Subject: [PATCH 1/4] mvsas: bug fix, null pointer may be used
> 
> Null pointer exception when mvi_dev is null.

A little more explanation might be helpful.  It looks to me that you get
this issue when you have in-flight I/O to a device we've been notified
has gone (because you NULL out lldd_dev in the removal notification
routine).

In which case, don't we have other races where this can happen, like in
mvs_I_T_nexus_reset()?

James

Re: [PATCH 1/4] mvsas: bugfix for NULL pointer execption

[Jeff Garzik]

James Bottomley wrote:
> On Fri, 2009-05-08 at 14:15 +0800, Ying Chu wrote:
>> >From 347191384292c6e9a9a572c657049bc11615fb82 Mon Sep 17 00:00:00 2001
>> From: Andy <ayan@marvell.com>
>> Date: Mon, 4 May 2009 23:29:26 +0800
>> Subject: [PATCH 1/4] mvsas: bug fix, null pointer may be used
>>
>> Null pointer exception when mvi_dev is null.
> 
> A little more explanation might be helpful.  It looks to me that you get
> this issue when you have in-flight I/O to a device we've been notified
> has gone (because you NULL out lldd_dev in the removal notification
> routine).
> 
> In which case, don't we have other races where this can happen, like in
> mvs_I_T_nexus_reset()?

Agreed...

RE: [PATCH 1/4] mvsas: bugfix for NULL pointer execption

[Andy Yan]

James,
	This case happens with irq coming late, the device may be gone when the irq is gotten, other cases are in normal stage, lldd_dev won't be null.

Regards
Andy Yan

-----Original Message-----
From: linux-scsi-owner@vger.kernel.org [mailto:linux-scsi-owner@vger.kernel.org] On Behalf Of Jeff Garzik
Sent: 2009年5月9日 6:06
To: James Bottomley
Cc: Ying Chu; linux-scsi@vger.kernel.org
Subject: Re: [PATCH 1/4] mvsas: bugfix for NULL pointer execption

James Bottomley wrote:
> On Fri, 2009-05-08 at 14:15 +0800, Ying Chu wrote:
>> >From 347191384292c6e9a9a572c657049bc11615fb82 Mon Sep 17 00:00:00 2001
>> From: Andy <ayan@marvell.com>
>> Date: Mon, 4 May 2009 23:29:26 +0800
>> Subject: [PATCH 1/4] mvsas: bug fix, null pointer may be used
>>
>> Null pointer exception when mvi_dev is null.
> 
> A little more explanation might be helpful.  It looks to me that you get
> this issue when you have in-flight I/O to a device we've been notified
> has gone (because you NULL out lldd_dev in the removal notification
> routine).
> 
> In which case, don't we have other races where this can happen, like in
> mvs_I_T_nexus_reset()?

Agreed...


--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html