From: Mike Christie <michaelc@cs.wisc.edu>
To: Eddie Wai <eddie.wai@broadcom.com>
Cc: James Bottomley <jbottomley@parallels.com>,
open-iscsi <open-iscsi@googlegroups.com>,
linux-scsi <linux-scsi@vger.kernel.org>,
Michael Chan <mchan@broadcom.com>,
Anil Veerabhadrappa <anilgv@broadcom.com>,
Ben Li <benli@broadcom.com>
Subject: Re: [PATCH] BNX2I: Fixed kernel panic caused by unprotected task->sc->request deref
Date: Wed, 07 Dec 2011 13:50:30 -0600 [thread overview]
Message-ID: <4EDFC386.9060708@cs.wisc.edu> (raw)
In-Reply-To: <1323240081-5328-1-git-send-email-eddie.wai@broadcom.com>
On 12/07/2011 12:41 AM, Eddie Wai wrote:
> During session recovery, the conn_stop call will trigger a flush
> to all outstanding SCSI cmds in the xmit queue. This will set
> all outstanding task->sc to NULL prior to the session_teardown
> call which frees the task memory.
>
> In the bnx2i SCSI response processing path, only the task was being checked
> for NULL under the session lock before the task->sc->request dereferencing.
> If there are outstanding SCSI cmd responses pending for process, the
> following kernel panic can be exposed where task->sc was found to be NULL.
>
> Call Trace:
> [ 69.720205] [<ffffffffa040d0d0>] bnx2i_process_new_cqes+0x290/0x3c0 [bnx2i]
> [ 69.804289] [<ffffffffa040d233>] bnx2i_fastpath_notification+0x33/0xa0 [bnx2
> i]
> [ 69.891490] [<ffffffffa040d37b>] bnx2i_indicate_kcqe+0xdb/0x330 [bnx2i]
> [ 69.971427] [<ffffffffa03eac5e>] service_kcqes+0x16e/0x1d0 [cnic]
> [ 70.045132] [<ffffffffa03eacea>] cnic_service_bnx2x_kcq+0x2a/0x50 [cnic]
> [ 70.126105] [<ffffffffa03ead53>] cnic_service_bnx2x_bh+0x43/0x140 [cnic]
> [ 70.207081] [<ffffffff81060676>] tasklet_action+0x66/0x110
> [ 70.273521] [<ffffffff8106025f>] __do_softirq+0xef/0x220
> [ 70.337887] [<ffffffff81447ebc>] call_softirq+0x1c/0x30
>
> This patch adds the !task->sc check and also protects the sc dereferencing
> under the session lock.
>
> Signed-off-by: Eddie Wai <eddie.wai@broadcom.com>
> ---
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
prev parent reply other threads:[~2011-12-07 19:50 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-07 6:41 [PATCH] BNX2I: Fixed kernel panic caused by unprotected task->sc->request deref Eddie Wai
2011-12-07 19:50 ` Mike Christie [this message]
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