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| author | Moger, Babu <Babu.Moger@netapp.com> | 2011-10-26 14:29:38 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-11-11 09:37:02 -0800 |
| commit | 51b702dc3de6c2b5ba3c091f755271776bce7ee4 (patch) | |
| tree | fc0631b45cda67e661276d43b6fca52f372e2768 | |
| parent | 292b3893b8e010398a338b482f40cbcd62e01a97 (diff) | |
| download | lwn-51b702dc3de6c2b5ba3c091f755271776bce7ee4.tar.gz lwn-51b702dc3de6c2b5ba3c091f755271776bce7ee4.zip | |
scsi_dh: check queuedata pointer before proceeding further
commit a18a920c70d48a8e4a2b750d8a183b3c1a4be514 upstream.
This patch validates sdev pointer in scsi_dh_activate before proceeding further.
Without this check we might see the panic as below. I have seen this
panic multiple times..
Call trace:
#0 [ffff88007d647b50] machine_kexec at ffffffff81020902
#1 [ffff88007d647ba0] crash_kexec at ffffffff810875b0
#2 [ffff88007d647c70] oops_end at ffffffff8139c650
#3 [ffff88007d647c90] __bad_area_nosemaphore at ffffffff8102dd15
#4 [ffff88007d647d50] page_fault at ffffffff8139b8cf
[exception RIP: scsi_dh_activate+0x82]
RIP: ffffffffa0041922 RSP: ffff88007d647e00 RFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000000000093c5
RDX: 00000000000093c5 RSI: ffffffffa02e6640 RDI: ffff88007cc88988
RBP: 000000000000000f R8: ffff88007d646000 R9: 0000000000000000
R10: ffff880082293790 R11: 00000000ffffffff R12: ffff88007cc88988
R13: 0000000000000000 R14: 0000000000000286 R15: ffff880037b845e0
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0000
#5 [ffff88007d647e38] run_workqueue at ffffffff81060268
#6 [ffff88007d647e78] worker_thread at ffffffff81060386
#7 [ffff88007d647ee8] kthread at ffffffff81064436
#8 [ffff88007d647f48] kernel_thread at ffffffff81003fba
Signed-off-by: Babu Moger <babu.moger@netapp.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | drivers/scsi/device_handler/scsi_dh.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c index 0119b8147797..d973325ded2a 100644 --- a/drivers/scsi/device_handler/scsi_dh.c +++ b/drivers/scsi/device_handler/scsi_dh.c @@ -398,7 +398,15 @@ int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data) spin_lock_irqsave(q->queue_lock, flags); sdev = q->queuedata; - if (sdev && sdev->scsi_dh_data) + if (!sdev) { + spin_unlock_irqrestore(q->queue_lock, flags); + err = SCSI_DH_NOSYS; + if (fn) + fn(data, err); + return err; + } + + if (sdev->scsi_dh_data) scsi_dh = sdev->scsi_dh_data->scsi_dh; dev = get_device(&sdev->sdev_gendev); if (!scsi_dh || !dev || |