From a878185c3b93e692ace0d1628a47f3d75504ab4f Mon Sep 17 00:00:00 2001 From: Eddie Wai Date: Tue, 6 Dec 2011 22:41:21 -0800 Subject: [SCSI] bnx2i: Fixed kernel panic caused by unprotected task->sc->request deref 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] [] bnx2i_process_new_cqes+0x290/0x3c0 [bnx2i] [ 69.804289] [] bnx2i_fastpath_notification+0x33/0xa0 [bnx2 i] [ 69.891490] [] bnx2i_indicate_kcqe+0xdb/0x330 [bnx2i] [ 69.971427] [] service_kcqes+0x16e/0x1d0 [cnic] [ 70.045132] [] cnic_service_bnx2x_kcq+0x2a/0x50 [cnic] [ 70.126105] [] cnic_service_bnx2x_bh+0x43/0x140 [cnic] [ 70.207081] [] tasklet_action+0x66/0x110 [ 70.273521] [] __do_softirq+0xef/0x220 [ 70.337887] [] 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 Signed-off-by: James Bottomley --- drivers/scsi/bnx2i/bnx2i_hwi.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'drivers/scsi/bnx2i') diff --git a/drivers/scsi/bnx2i/bnx2i_hwi.c b/drivers/scsi/bnx2i/bnx2i_hwi.c index dba72a4e6a1c..1ad0b8225560 100644 --- a/drivers/scsi/bnx2i/bnx2i_hwi.c +++ b/drivers/scsi/bnx2i/bnx2i_hwi.c @@ -1906,18 +1906,19 @@ static int bnx2i_queue_scsi_cmd_resp(struct iscsi_session *session, spin_lock(&session->lock); task = iscsi_itt_to_task(bnx2i_conn->cls_conn->dd_data, cqe->itt & ISCSI_CMD_RESPONSE_INDEX); - if (!task) { + if (!task || !task->sc) { spin_unlock(&session->lock); return -EINVAL; } sc = task->sc; - spin_unlock(&session->lock); if (!blk_rq_cpu_valid(sc->request)) cpu = smp_processor_id(); else cpu = sc->request->cpu; + spin_unlock(&session->lock); + p = &per_cpu(bnx2i_percpu, cpu); spin_lock(&p->p_work_lock); if (unlikely(!p->iothread)) { -- cgit v1.2.3-59-g8ed1b