diff options
| author | Douglas Gilbert <dgilbert@interlog.com> | 2014-08-31 23:09:59 (GMT) |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2014-09-30 07:34:37 (GMT) |
| commit | db525fce95f0ee39102f06f8599ced3f3f3af128 (patch) | |
| tree | 104a30ca4d06b3d62234a06007e192ff4ecc3fdb | |
| parent | a41a9ad3bbf61fae0b6bfb232153da60d14fdbd9 (diff) | |
| download | linux-db525fce95f0ee39102f06f8599ced3f3f3af128.tar.xz | |
scsi_debug: deadlock between completions and surprise module removal
A deadlock has been reported when the completion
of SCSI commands (simulated by a timer) was surprised
by a module removal. This patch removes one half of
the offending locks around timer deletions. This fix
is applied both to stop_all_queued() which is were
the deadlock was discovered and stop_queued_cmnd()
which has very similar logic.
This patch should be applied both to the lk 3.17 tree
and Christoph's drivers-for-3.18 tree.
Tested-and-reported-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
| -rw-r--r-- | drivers/scsi/scsi_debug.c | 33 |
1 files changed, 19 insertions, 14 deletions
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c index 1c475e9..2b6d447 100644 --- a/drivers/scsi/scsi_debug.c +++ b/drivers/scsi/scsi_debug.c @@ -2743,6 +2743,13 @@ static int stop_queued_cmnd(struct scsi_cmnd *cmnd) if (test_bit(k, queued_in_use_bm)) { sqcp = &queued_arr[k]; if (cmnd == sqcp->a_cmnd) { + devip = (struct sdebug_dev_info *) + cmnd->device->hostdata; + if (devip) + atomic_dec(&devip->num_in_q); + sqcp->a_cmnd = NULL; + spin_unlock_irqrestore(&queued_arr_lock, + iflags); if (scsi_debug_ndelay > 0) { if (sqcp->sd_hrtp) hrtimer_cancel( @@ -2755,18 +2762,13 @@ static int stop_queued_cmnd(struct scsi_cmnd *cmnd) if (sqcp->tletp) tasklet_kill(sqcp->tletp); } - __clear_bit(k, queued_in_use_bm); - devip = (struct sdebug_dev_info *) - cmnd->device->hostdata; - if (devip) - atomic_dec(&devip->num_in_q); - sqcp->a_cmnd = NULL; - break; + clear_bit(k, queued_in_use_bm); + return 1; } } } spin_unlock_irqrestore(&queued_arr_lock, iflags); - return (k < qmax) ? 1 : 0; + return 0; } /* Deletes (stops) timers or tasklets of all queued commands */ @@ -2782,6 +2784,13 @@ static void stop_all_queued(void) if (test_bit(k, queued_in_use_bm)) { sqcp = &queued_arr[k]; if (sqcp->a_cmnd) { + devip = (struct sdebug_dev_info *) + sqcp->a_cmnd->device->hostdata; + if (devip) + atomic_dec(&devip->num_in_q); + sqcp->a_cmnd = NULL; + spin_unlock_irqrestore(&queued_arr_lock, + iflags); if (scsi_debug_ndelay > 0) { if (sqcp->sd_hrtp) hrtimer_cancel( @@ -2794,12 +2803,8 @@ static void stop_all_queued(void) if (sqcp->tletp) tasklet_kill(sqcp->tletp); } - __clear_bit(k, queued_in_use_bm); - devip = (struct sdebug_dev_info *) - sqcp->a_cmnd->device->hostdata; - if (devip) - atomic_dec(&devip->num_in_q); - sqcp->a_cmnd = NULL; + clear_bit(k, queued_in_use_bm); + spin_lock_irqsave(&queued_arr_lock, iflags); } } } |