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| author | Joe Lawrence <Joe.Lawrence@stratus.com> | 2013-03-05 16:57:56 +0100 |
|---|---|---|
| committer | James Bottomley <JBottomley@Parallels.com> | 2013-04-06 12:14:20 +0200 |
| commit | 2b5bebccd282f2527d17ac90cf3ad0d486dd89d8 (patch) | |
| tree | 6fdef4e36e3e4d4cfef58d37c06bcfd86ff63557 /drivers/scsi/st.c | |
| parent | [SCSI] libsas: use right function to alloc smp response (diff) | |
| download | linux-2b5bebccd282f2527d17ac90cf3ad0d486dd89d8.tar.xz linux-2b5bebccd282f2527d17ac90cf3ad0d486dd89d8.zip | |
[SCSI] st: Take additional queue ref in st_probe
This patch fixes a reference count bug in the SCSI tape driver which can be
reproduced with the following:
* Boot with slub_debug=FZPU, tape drive attached
* echo 1 > /sys/devices/... tape device pci path .../remove
* Wait for device removal
* echo 1 > /sys/kernel/slab/blkdev_queue/validate
* Slub debug complains about corrupted poison pattern
In commit 523e1d39 (block: make gendisk hold a reference to its queue)
add_disk() and disk_release() were modified to get/put an additional
reference on a disk queue to fix a reference counting discrepency
between bdev release and SCSI device removal. The ST driver never
calls add_disk(), so this commit introduced an extra kref put when the
ST driver frees its struct gendisk.
Attempts were made to fix this bug at the block level [1] but later
abandoned due to floppy driver issues [2].
[1] https://lkml.org/lkml/2012/8/27/354
[2] https://lkml.org/lkml/2012/9/22/113
Signed-off-by: Joe Lawrence <joe.lawrence@stratus.com>
Tested-by: Ewan D. Milne <emilne@redhat.com>
Acked-by: Kai Mäkisara <Kai.Makisara@kolumbus.fi>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Diffstat (limited to 'drivers/scsi/st.c')
| -rw-r--r-- | drivers/scsi/st.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c index 86974471af68..2a32036a9404 100644 --- a/drivers/scsi/st.c +++ b/drivers/scsi/st.c @@ -4112,6 +4112,10 @@ static int st_probe(struct device *dev) tpnt->disk = disk; disk->private_data = &tpnt->driver; disk->queue = SDp->request_queue; + /* SCSI tape doesn't register this gendisk via add_disk(). Manually + * take queue reference that release_disk() expects. */ + if (!blk_get_queue(disk->queue)) + goto out_put_disk; tpnt->driver = &st_template; tpnt->device = SDp; @@ -4185,7 +4189,7 @@ static int st_probe(struct device *dev) idr_preload_end(); if (error < 0) { pr_warn("st: idr allocation failed: %d\n", error); - goto out_put_disk; + goto out_put_queue; } tpnt->index = error; sprintf(disk->disk_name, "st%d", tpnt->index); @@ -4211,6 +4215,8 @@ out_remove_devs: spin_lock(&st_index_lock); idr_remove(&st_index_idr, tpnt->index); spin_unlock(&st_index_lock); +out_put_queue: + blk_put_queue(disk->queue); out_put_disk: put_disk(disk); kfree(tpnt); |