diff options
| author | Bart Van Assche <bart.vanassche@wdc.com> | 2017-08-17 13:12:45 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-09-27 11:00:14 +0200 |
| commit | 0bcaf5178fe6cc3169d4ef47e92e84e938bf7b3c (patch) | |
| tree | f36c8c318736d93e50d82beb66f034fee8d08d8a | |
| parent | f05dafbd779112307e8dfe0ed8226910d29f0020 (diff) | |
skd: Avoid that module unloading triggers a use-after-free
commit 7277cc67b3916eed47558c64f9c9c0de00a35cda upstream.
Since put_disk() triggers a disk_release() call and since that
last function calls blk_put_queue() if disk->queue != NULL, clear
the disk->queue pointer before calling put_disk(). This avoids
that unloading the skd kernel module triggers the following
use-after-free:
WARNING: CPU: 8 PID: 297 at lib/refcount.c:128 refcount_sub_and_test+0x70/0x80
refcount_t: underflow; use-after-free.
CPU: 8 PID: 297 Comm: kworker/8:1 Not tainted 4.11.10-300.fc26.x86_64 #1
Workqueue: events work_for_cpu_fn
Call Trace:
dump_stack+0x63/0x84
__warn+0xcb/0xf0
warn_slowpath_fmt+0x5a/0x80
refcount_sub_and_test+0x70/0x80
refcount_dec_and_test+0x11/0x20
kobject_put+0x1f/0x50
blk_put_queue+0x15/0x20
disk_release+0xae/0xf0
device_release+0x32/0x90
kobject_release+0x67/0x170
kobject_put+0x2b/0x50
put_disk+0x17/0x20
skd_destruct+0x5c/0x890 [skd]
skd_pci_probe+0x124d/0x13a0 [skd]
local_pci_probe+0x42/0xa0
work_for_cpu_fn+0x14/0x20
process_one_work+0x19e/0x470
worker_thread+0x1dc/0x4a0
kthread+0x125/0x140
ret_from_fork+0x25/0x30
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/block/skd_main.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/drivers/block/skd_main.c b/drivers/block/skd_main.c index 586f9168ffa4..a1f8bf96d8b3 100644 --- a/drivers/block/skd_main.c +++ b/drivers/block/skd_main.c @@ -4679,15 +4679,16 @@ static void skd_free_disk(struct skd_device *skdev) { struct gendisk *disk = skdev->disk; - if (disk != NULL) { - struct request_queue *q = disk->queue; + if (disk && (disk->flags & GENHD_FL_UP)) + del_gendisk(disk); - if (disk->flags & GENHD_FL_UP) - del_gendisk(disk); - if (q) - blk_cleanup_queue(q); - put_disk(disk); + if (skdev->queue) { + blk_cleanup_queue(skdev->queue); + skdev->queue = NULL; + disk->queue = NULL; } + + put_disk(disk); skdev->disk = NULL; } |