diff options
| author |   Alexey Dobriyan <adobriyan@gmail.com> | 2009-10-26 16:49:55 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2009-10-29 07:39:27 -0700 |
| commit | cf6e693212263d33c5882e4653df89a2fca4c0c4 (patch) | |
| tree | 9774d1776e7d79aaacb2ab77d342e5e24e925462 /drivers/block/loop.c | |
| parent | vmscan: limit VM_EXEC protection to file pages (diff) | |
| download | linux-dev-cf6e693212263d33c5882e4653df89a2fca4c0c4.tar.xz linux-dev-cf6e693212263d33c5882e4653df89a2fca4c0c4.zip | |
loop: fix NULL dereference if mount fails
Commit bb21488482bd36eae6b30b014d93619063773fd4 ("[PATCH] switch loop")
started to pass NULL bdev to ioctl hook.
Steps to reproduce:
[boot with loop.max_part=1]
[mount -o loop something so mount fails]
BUG: unable to handle kernel NULL pointer dereference at 00000000000000b8
IP: [<ffffffff811486ee>] blkdev_ioctl+0x2e/0xa30
PGD 0
Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
last sysfs file: /sys/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:35/ACPI0003:00/power_supply/ACAD/online
CPU 0
Modules linked in: zfs nvidia(P) [last unloaded: zfs]
Pid: 15177, comm: mount Tainted: P 2.6.32-rc4-zfs #2 Satellite X200
RIP: 0010:[<ffffffff811486ee>] [<ffffffff811486ee>] blkdev_ioctl+0x2e/0xa30
RSP: 0018:ffff88003b3d5bb8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 000000000000125f RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88003b3d5ce8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 00007ffffffff000
R13: 0000000000000000 R14: ffff880071cef280 R15: 00000000000200da
FS: 00007fd77cfe7740(0000) GS:ffff880001600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00000000000000b8 CR3: 0000000001001000 CR4: 00000000000026f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process mount (pid: 15177, threadinfo ffff88003b3d4000, task ffff88007572f920)
Stack:
ffff88003b3d5c38 ffffffff812f95f5 ffff88007eeb6600 0000000000000000
<0> 0000000000000000 ffff88003b3d5c18 ffffffff811547d9 ffff88001bf11ef0
<0> 7fffffffffffffff ffff88001bf11ee8 ffff88001bf11ef0 0000000000000000
Call Trace:
[<ffffffff812f95f5>] ? schedule_timeout+0x1f5/0x250
[<ffffffff811547d9>] ? rb_insert_color+0x109/0x140
[<ffffffff812fb754>] ? _spin_unlock_irq+0x14/0x40
[<ffffffff812f84c6>] ? wait_for_common+0x66/0x170
[<ffffffff8105a280>] ? default_wake_function+0x0/0x10
[<ffffffff810f8258>] ioctl_by_bdev+0x38/0x50
[<ffffffff811d2481>] loop_clr_fd+0x1e1/0x210
[<ffffffff811d2522>] lo_release+0x72/0x80
[<ffffffff810f934c>] __blkdev_put+0x1ac/0x1d0
[<ffffffff810f937b>] blkdev_put+0xb/0x10
[<ffffffff810f93b9>] blkdev_close+0x39/0x60
[<ffffffff810ccef3>] __fput+0xd3/0x230
[<ffffffff810cd06d>] fput+0x1d/0x30
[<ffffffff810c9680>] filp_close+0x50/0x80
[<ffffffff81061f11>] put_files_struct+0x81/0x100
[<ffffffff81061fde>] exit_files+0x4e/0x60
[<ffffffff81063ec5>] do_exit+0x6b5/0x730
[<ffffffff8107b279>] ? up_read+0x9/0x10
[<ffffffff8104c86e>] ? do_page_fault+0x18e/0x2a0
[<ffffffff81063f81>] do_group_exit+0x41/0xc0
[<ffffffff81064012>] sys_exit_group+0x12/0x20
[<ffffffff81030deb>] system_call_fastpath+0x16/0x1b
Code: f8 48 89 e5 48 81 ec 30 01 00 00 48 89 5d d8 4c 89 6d e8 4c 89 65 e0 4c 89 75 f0 4c 89 7d f8 48 89 bd e8 fe ff ff 49 89 cd 89 f3 <49> 8b 88 b8 00 00 00 81 fa 68 12 00 00 0f 84 57 05 00 00 0f 86
RIP [<ffffffff811486ee>] blkdev_ioctl+0x2e/0xa30
RSP <ffff88003b3d5bb8>
CR2: 00000000000000b8
---[ end trace c0b4d3c3118d1427 ]---
Fixing recursive fault but reboot is needed!
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/block/loop.c')
| -rw-r--r-- | drivers/block/loop.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c index edda9ea7c626..bd112c8c7bcd 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -949,7 +949,7 @@ static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev) lo->lo_state = Lo_unbound; /* This is safe: open() is still holding a reference. */ module_put(THIS_MODULE); - if (max_part > 0) + if (max_part > 0 && bdev) ioctl_by_bdev(bdev, BLKRRPART, 0); mutex_unlock(&lo->lo_ctl_mutex); /* |