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| author | Ming Lei <ming.lei@redhat.com> | 2024-12-25 19:06:40 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2024-12-26 06:42:55 -0700 |
| commit | 75cd4005da5492129917a4a4ee45e81660556104 (patch) | |
| tree | a74812e05a2ad1a767e955e691696980ca3940c5 | |
| parent | 85672ca9ceeaa1dcf2777a7048af5f4aee3fd02b (diff) | |
| download | lwn-75cd4005da5492129917a4a4ee45e81660556104.tar.gz lwn-75cd4005da5492129917a4a4ee45e81660556104.zip | |
ublk: detach gendisk from ublk device if add_disk() fails
Inside ublk_abort_requests(), gendisk is grabbed for aborting all
inflight requests. And ublk_abort_requests() is called when exiting
the uring context or handling timeout.
If add_disk() fails, the gendisk may have been freed when calling
ublk_abort_requests(), so use-after-free can be caused when getting
disk's reference in ublk_abort_requests().
Fixes the bug by detaching gendisk from ublk device if add_disk() fails.
Fixes: bd23f6c2c2d0 ("ublk: quiesce request queue when aborting queue")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20241225110640.351531-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | drivers/block/ublk_drv.c | 26 |
1 files changed, 17 insertions, 9 deletions
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index d4aed12dd436..934ab9332c80 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -1618,6 +1618,21 @@ static void ublk_unquiesce_dev(struct ublk_device *ub) blk_mq_kick_requeue_list(ub->ub_disk->queue); } +static struct gendisk *ublk_detach_disk(struct ublk_device *ub) +{ + struct gendisk *disk; + + /* Sync with ublk_abort_queue() by holding the lock */ + spin_lock(&ub->lock); + disk = ub->ub_disk; + ub->dev_info.state = UBLK_S_DEV_DEAD; + ub->dev_info.ublksrv_pid = -1; + ub->ub_disk = NULL; + spin_unlock(&ub->lock); + + return disk; +} + static void ublk_stop_dev(struct ublk_device *ub) { struct gendisk *disk; @@ -1631,14 +1646,7 @@ static void ublk_stop_dev(struct ublk_device *ub) ublk_unquiesce_dev(ub); } del_gendisk(ub->ub_disk); - - /* Sync with ublk_abort_queue() by holding the lock */ - spin_lock(&ub->lock); - disk = ub->ub_disk; - ub->dev_info.state = UBLK_S_DEV_DEAD; - ub->dev_info.ublksrv_pid = -1; - ub->ub_disk = NULL; - spin_unlock(&ub->lock); + disk = ublk_detach_disk(ub); put_disk(disk); unlock: mutex_unlock(&ub->mutex); @@ -2336,7 +2344,7 @@ static int ublk_ctrl_start_dev(struct ublk_device *ub, struct io_uring_cmd *cmd) out_put_cdev: if (ret) { - ub->dev_info.state = UBLK_S_DEV_DEAD; + ublk_detach_disk(ub); ublk_put_device(ub); } if (ret) |