@@ -2579,14 +2579,14 @@ static int pkt_new_dev(struct pktcdvd_device *pd, dev_t dev)
bdev = bdget(dev);
if (!bdev)
return -ENOMEM;
+ ret = blkdev_get(bdev, FMODE_READ | FMODE_NDELAY, NULL);
+ if (ret)
+ return ret;
if (!blk_queue_scsi_passthrough(bdev_get_queue(bdev))) {
WARN_ONCE(true, "Attempt to register a non-SCSI queue\n");
- bdput(bdev);
+ blkdev_put(bdev, FMODE_READ | FMODE_NDELAY);
return -EINVAL;
}
- ret = blkdev_get(bdev, FMODE_READ | FMODE_NDELAY, NULL);
- if (ret)
- return ret;
/* This is safe, since we have a reference from open(). */
__module_get(THIS_MODULE);
Call bdev_get_queue(bdev) after bdev->bd_disk has been initialized instead of just before that pointer has been initialized. This patch avoids that the following command pktsetup 1 /dev/sr0 triggers the following kernel crash: BUG: unable to handle kernel NULL pointer dereference at 0000000000000548 IP: pkt_setup_dev+0x2db/0x670 [pktcdvd] CPU: 2 PID: 724 Comm: pktsetup Not tainted 4.15.0-rc4-dbg+ #1 Call Trace: pkt_ctl_ioctl+0xce/0x1c0 [pktcdvd] do_vfs_ioctl+0x8e/0x670 SyS_ioctl+0x3c/0x70 entry_SYSCALL_64_fastpath+0x23/0x9a Reported-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name> Fixes: commit ca18d6f769d2 ("block: Make most scsi_req_init() calls implicit") Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Tested-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name> Cc: Maciej S. Szmigiero <mail@maciej.szmigiero.name> Cc: <stable@vger.kernel.org> # v4.13 --- drivers/block/pktcdvd.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)