block: don't allow a disk link holder to itself
After creating a dm device, then user can reload such dm with itself,
and dead loop will be triggered because dm keep looking up to itself.
Test procedures:
1) dmsetup create test --table "xxx sda", assume dm-0 is created
2) dmsetup suspend test
3) dmsetup reload test --table "xxx dm-0"
4) dmsetup resume test
Test result:
BUG: TASK stack guard page was hit at
00000000736a261f (stack is
000000008d12c88d..
00000000c8dd82d5)
stack guard page: 0000 [#1] PREEMPT SMP
CPU: 29 PID: 946 Comm: systemd-udevd Not tainted
6.1.0-rc3-next-20221101-00006-g17640ca3b0ee #1295
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014
RIP: 0010:dm_prepare_ioctl+0xf/0x1e0
Code: da 48 83 05 4a 7c 99 0b 01 41 89 c4 eb cd e8 b8 1f 40 00 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 41 57 48 83 05 a1 5a 99 0b 01 <41> 56 49 89 d6 41 55 4c 8d af 90 02 00 00 9
RSP: 0018:
ffffc90002090000 EFLAGS:
00010206
RAX:
ffff8881049d6800 RBX:
ffff88817e589000 RCX:
0000000000000000
RDX:
ffffc90002090010 RSI:
ffffc9000209001c RDI:
ffff88817e589000
RBP:
00000000484a101d R08:
0000000000000000 R09:
0000000000000007
R10:
0000000000000000 R11:
0000000000000000 R12:
0000000000005331
R13:
0000000000005331 R14:
0000000000000000 R15:
0000000000000000
FS:
00007fddf9609200(0000) GS:
ffff889fbfd40000(0000) knlGS:
0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0:
0000000080050033
CR2:
ffffc9000208fff8 CR3:
0000000179043000 CR4:
00000000000006e0
DR0:
0000000000000000 DR1:
0000000000000000 DR2:
0000000000000000
DR3:
0000000000000000 DR6:
00000000fffe0ff0 DR7:
0000000000000400
Call Trace:
<TASK>
dm_blk_ioctl+0x50/0x1c0
? dm_prepare_ioctl+0xe0/0x1e0
dm_blk_ioctl+0x88/0x1c0
dm_blk_ioctl+0x88/0x1c0
......(a lot of same lines)
dm_blk_ioctl+0x88/0x1c0
dm_blk_ioctl+0x88/0x1c0
blkdev_ioctl+0x184/0x3e0
__x64_sys_ioctl+0xa3/0x110
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fddf7306577
Code: b3 66 90 48 8b 05 11 89 2c 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e1 88 8
RSP: 002b:
00007ffd0b2ec318 EFLAGS:
00000246 ORIG_RAX:
0000000000000010
RAX:
ffffffffffffffda RBX:
00005634ef478320 RCX:
00007fddf7306577
RDX:
0000000000000000 RSI:
0000000000005331 RDI:
0000000000000007
RBP:
0000000000000007 R08:
00005634ef4843e0 R09:
0000000000000080
R10:
00007fddf75cfb38 R11:
0000000000000246 R12:
00000000030d4000
R13:
0000000000000000 R14:
0000000000000000 R15:
00005634ef48b800
</TASK>
Modules linked in:
---[ end trace
0000000000000000 ]---
RIP: 0010:dm_prepare_ioctl+0xf/0x1e0
Code: da 48 83 05 4a 7c 99 0b 01 41 89 c4 eb cd e8 b8 1f 40 00 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 41 57 48 83 05 a1 5a 99 0b 01 <41> 56 49 89 d6 41 55 4c 8d af 90 02 00 00 9
RSP: 0018:
ffffc90002090000 EFLAGS:
00010206
RAX:
ffff8881049d6800 RBX:
ffff88817e589000 RCX:
0000000000000000
RDX:
ffffc90002090010 RSI:
ffffc9000209001c RDI:
ffff88817e589000
RBP:
00000000484a101d R08:
0000000000000000 R09:
0000000000000007
R10:
0000000000000000 R11:
0000000000000000 R12:
0000000000005331
R13:
0000000000005331 R14:
0000000000000000 R15:
0000000000000000
FS:
00007fddf9609200(0000) GS:
ffff889fbfd40000(0000) knlGS:
0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0:
0000000080050033
CR2:
ffffc9000208fff8 CR3:
0000000179043000 CR4:
00000000000006e0
DR0:
0000000000000000 DR1:
0000000000000000 DR2:
0000000000000000
DR3:
0000000000000000 DR6:
00000000fffe0ff0 DR7:
0000000000000400
Kernel panic - not syncing: Fatal exception in interrupt
Kernel Offset: disabled
---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---
Fix the problem by forbidding a disk to create link to itself.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221115141054.1051801-11-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>