divide error in blk_stack_limits

Status: upstream: reported C repro on 2026/10/24 21:37
Subsystems: block
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+1288484b13bf6af3620d@syzkaller.appspotmail.com
First crash: 4d01h, last: 3h05m
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ID Workflow Result Correct Bug Created Started Finished Revision
a656467a assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ divide error in blk_stack_limits 2026/10/21 00:10 2026/10/21 00:10 2026/10/21 01:02 61c200c7
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Title Replies (including bot) Last reply
[syzbot] [block?] divide error in blk_stack_limits 0 (1) 2026/10/24 21:37

Sample crash report:
Oops: divide error: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5481 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:queue_limit_discard_alignment block/blk-settings.c:645 [inline]
RIP: 0010:blk_stack_limits+0x1105/0x2d00 block/blk-settings.c:916
Code: 68 48 4c 89 e8 48 c1 e8 03 0f b6 04 18 84 c0 0f 85 7c 18 00 00 45 8b 65 00 c7 44 24 10 00 00 00 00 eb 5f 48 8b 44 24 48 31 d2 <41> f7 f5 44 01 e9 29 d1 89 c8 31 d2 41 f7 f5 48 8b 44 24 08 4c 8d
RSP: 0018:ffffc90001c0f4f8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: 0000000000000000
RBP: ffffc90001c0f850 R08: ffffc90001c0f7e0 R09: 1ffffffff37b4dc0
R10: dffffc0000000000 R11: ffffffff88a11a10 R12: 00000000ffffffff
R13: 0000000000000000 R14: 1ffff92000381f0a R15: ffffc90001c0f854
FS:  0000555570175500(0000) GS:ffff88808b0b0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa930071220 CR3: 000000003cf9f000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 dm_calculate_queue_limits+0x70c/0x1510 drivers/md/dm-table.c:1823
 dm_setup_md_queue+0x199/0x4f0 drivers/md/dm.c:2618
 table_load+0x4fd/0x8a0 drivers/md/dm-ioctl.c:1661
 ctl_ioctl drivers/md/dm-ioctl.c:2221 [inline]
 dm_ctl_ioctl+0x9ec/0xe10 drivers/md/dm-ioctl.c:2243
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa93019f559
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffce7b56638 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fa930425fa0 RCX: 00007fa93019f559
RDX: 0000200000000640 RSI: 00000000c138fd09 RDI: 0000000000000003
RBP: 00007fa930236b20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa930425fac R14: 00007fa930425fa0 R15: 00007fa930425fa0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:queue_limit_discard_alignment block/blk-settings.c:645 [inline]
RIP: 0010:blk_stack_limits+0x1105/0x2d00 block/blk-settings.c:916
Code: 68 48 4c 89 e8 48 c1 e8 03 0f b6 04 18 84 c0 0f 85 7c 18 00 00 45 8b 65 00 c7 44 24 10 00 00 00 00 eb 5f 48 8b 44 24 48 31 d2 <41> f7 f5 44 01 e9 29 d1 89 c8 31 d2 41 f7 f5 48 8b 44 24 08 4c 8d
RSP: 0018:ffffc90001c0f4f8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: 0000000000000000
RBP: ffffc90001c0f850 R08: ffffc90001c0f7e0 R09: 1ffffffff37b4dc0
R10: dffffc0000000000 R11: ffffffff88a11a10 R12: 00000000ffffffff
R13: 0000000000000000 R14: 1ffff92000381f0a R15: ffffc90001c0f854
FS:  0000555570175500(0000) GS:ffff88808b0b0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa930071220 CR3: 000000003cf9f000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
   0:	68 48 4c 89 e8       	push   $0xffffffffe8894c48
   5:	48 c1 e8 03          	shr    $0x3,%rax
   9:	0f b6 04 18          	movzbl (%rax,%rbx,1),%eax
   d:	84 c0                	test   %al,%al
   f:	0f 85 7c 18 00 00    	jne    0x1891
  15:	45 8b 65 00          	mov    0x0(%r13),%r12d
  19:	c7 44 24 10 00 00 00 	movl   $0x0,0x10(%rsp)
  20:	00
  21:	eb 5f                	jmp    0x82
  23:	48 8b 44 24 48       	mov    0x48(%rsp),%rax
  28:	31 d2                	xor    %edx,%edx
* 2a:	41 f7 f5             	div    %r13d <-- trapping instruction
  2d:	44 01 e9             	add    %r13d,%ecx
  30:	29 d1                	sub    %edx,%ecx
  32:	89 c8                	mov    %ecx,%eax
  34:	31 d2                	xor    %edx,%edx
  36:	41 f7 f5             	div    %r13d
  39:	48 8b 44 24 08       	mov    0x8(%rsp),%rax
  3e:	4c                   	rex.WR
  3f:	8d                   	.byte 0x8d

Crashes (33):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/20 22:24 upstream f47d223627f8 df8746fb .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root divide error in blk_stack_limits
2026/10/20 21:58 upstream f47d223627f8 df8746fb .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root divide error in blk_stack_limits
2026/10/24 19:09 upstream 26344c0dd32a 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root divide error in blk_stack_limits
2026/10/24 19:09 upstream 26344c0dd32a 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root divide error in blk_stack_limits
2026/10/24 10:29 upstream 26344c0dd32a 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root divide error in blk_stack_limits
2026/10/24 10:29 upstream 26344c0dd32a 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root divide error in blk_stack_limits
2026/10/24 09:56 upstream 4169c9c90532 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root divide error in blk_stack_limits
2026/10/24 09:55 upstream 4169c9c90532 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root divide error in blk_stack_limits
2026/10/24 08:15 upstream 4da9dedf3fc5 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root divide error in blk_stack_limits
2026/10/24 07:47 upstream 4169c9c90532 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root divide error in blk_stack_limits
2026/10/24 07:46 upstream 4169c9c90532 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root divide error in blk_stack_limits
2026/10/24 06:00 upstream 4169c9c90532 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root divide error in blk_stack_limits
2026/10/24 06:00 upstream 4169c9c90532 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root divide error in blk_stack_limits
2026/10/24 03:06 upstream 4169c9c90532 d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root divide error in blk_stack_limits
2026/10/23 20:57 upstream 734bef548a96 d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root divide error in blk_stack_limits
2026/10/23 19:35 upstream 734bef548a96 d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root divide error in blk_stack_limits
2026/10/23 19:35 upstream 734bef548a96 d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root divide error in blk_stack_limits
2026/10/23 15:13 upstream 734bef548a96 d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root divide error in blk_stack_limits
2026/10/23 15:13 upstream 734bef548a96 d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root divide error in blk_stack_limits
2026/10/21 01:42 upstream f47d223627f8 df8746fb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root divide error in blk_stack_limits
2026/10/24 20:10 upstream 5b0764a53235 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream divide error in blk_stack_limits
2026/10/24 17:33 upstream 5b0764a53235 1d9ca40b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root divide error in blk_stack_limits
2026/10/23 22:54 upstream 734bef548a96 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream divide error in blk_stack_limits
2026/10/23 16:13 upstream 734bef548a96 1d9ca40b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root divide error in blk_stack_limits
2026/10/22 23:23 upstream 7be4bc52fd9e 3875c4e4 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream divide error in blk_stack_limits
2026/10/22 23:22 upstream 7be4bc52fd9e 3875c4e4 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream divide error in blk_stack_limits
2026/10/22 16:51 upstream 7be4bc52fd9e b55fad29 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root divide error in blk_stack_limits
2026/10/21 02:18 upstream 4a8bdffce502 61c200c7 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root divide error in blk_stack_limits
2026/10/20 21:30 upstream f47d223627f8 df8746fb .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root divide error in blk_stack_limits
2026/10/23 09:14 upstream 3ac032ef6ca8 d566bfda .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 divide error in blk_stack_limits
2026/10/24 16:36 linux-next 20a33c6b6cbe 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root divide error in blk_stack_limits
2026/10/23 13:12 linux-next bd1ecbb61afe d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root divide error in blk_stack_limits
2026/10/23 13:12 linux-next bd1ecbb61afe d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root divide error in blk_stack_limits
* Struck through repros no longer work on HEAD.