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| author | Bart Van Assche <bart.vanassche@wdc.com> | 2018-01-02 11:39:48 -0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-01-05 09:03:04 -0700 |
| commit | 882d4171a8950646413b1a3cbe0e4a6a612fe82e (patch) | |
| tree | 92dd5094dad515ec3003900354d96f50098df1df | |
| parent | 5a0ec388ef0f6e33841aeb810d7fa23f049ec4cd (diff) | |
| download | linux-882d4171a8950646413b1a3cbe0e4a6a612fe82e.tar.gz linux-882d4171a8950646413b1a3cbe0e4a6a612fe82e.tar.xz | |
pktcdvd: Fix a recently introduced NULL pointer dereference
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
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | drivers/block/pktcdvd.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c index 2659b2534073..531a0915066b 100644 --- a/drivers/block/pktcdvd.c +++ b/drivers/block/pktcdvd.c @@ -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); |