syzbot


general protection fault in iomap_dio_bio_end_io

Status: upstream: reported C repro on 2026/01/12 06:55
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+2edeeffc0f94c716da9b@syzkaller.appspotmail.com
First crash: 7d12h, last: 4d03h
Bug presence (2)
Date Name Commit Repro Result
2026/01/14 linux-6.6.y (ToT) c596736dadab C [report] general protection fault in iomap_dio_bio_end_io
2026/01/14 upstream (ToT) c537e12daeec C Didn't crash
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream general protection fault in iomap_dio_bio_end_io ext4 iomap 2 C error 16 53d 56d 29/29 fixed on 2026/01/07 12:29

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000038: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000001c0-0x00000000000001c7]
CPU: 0 PID: 16 Comm: ksoftirqd/0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__queue_work+0xa7/0x1020 kernel/workqueue.c:1725
Code: ee e8 ad 38 2f 00 85 ed 0f 85 db 0c 00 00 e8 f0 34 2f 00 48 89 1c 24 49 8d af c0 01 00 00 48 89 e8 48 c1 e8 03 48 89 44 24 48 <42> 0f b6 04 28 84 c0 0f 85 05 0d 00 00 8b 5d 00 89 de 81 e6 00 80
RSP: 0018:ffffc900001579d0 EFLAGS: 00010002
RAX: 0000000000000038 RBX: ffff88802e356c40 RCX: ffff88801be5da00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00000000000001c0 R08: ffff88802e356c47 R09: 1ffff11005c6ad88
R10: dffffc0000000000 R11: ffffed1005c6ad89 R12: 0000000000000008
R13: dffffc0000000000 R14: ffff88802e356c40 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000006ad000 CR3: 000000002e2a1000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 queue_work_on+0x121/0x1e0 kernel/workqueue.c:1835
 queue_work include/linux/workqueue.h:562 [inline]
 iomap_dio_done fs/iomap/direct-io.c:222 [inline]
 iomap_dio_bio_end_io+0x462/0x630 fs/iomap/direct-io.c:235
 req_bio_endio block/blk-mq.c:786 [inline]
 blk_update_request+0x597/0xe40 block/blk-mq.c:931
 blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1058
 blk_complete_reqs block/blk-mq.c:1138 [inline]
 blk_done_softirq+0x10b/0x160 block/blk-mq.c:1143
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 run_ksoftirqd+0x9c/0xf0 kernel/softirq.c:950
 smpboot_thread_fn+0x635/0xa00 kernel/smpboot.c:164
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__queue_work+0xa7/0x1020 kernel/workqueue.c:1725
Code: ee e8 ad 38 2f 00 85 ed 0f 85 db 0c 00 00 e8 f0 34 2f 00 48 89 1c 24 49 8d af c0 01 00 00 48 89 e8 48 c1 e8 03 48 89 44 24 48 <42> 0f b6 04 28 84 c0 0f 85 05 0d 00 00 8b 5d 00 89 de 81 e6 00 80
RSP: 0018:ffffc900001579d0 EFLAGS: 00010002
RAX: 0000000000000038 RBX: ffff88802e356c40 RCX: ffff88801be5da00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00000000000001c0 R08: ffff88802e356c47 R09: 1ffff11005c6ad88
R10: dffffc0000000000 R11: ffffed1005c6ad89 R12: 0000000000000008
R13: dffffc0000000000 R14: ffff88802e356c40 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000006ad000 CR3: 000000002e2a1000 CR4: 00000000003506f0
----------------
Code disassembly (best guess):
   0:	ee                   	out    %al,(%dx)
   1:	e8 ad 38 2f 00       	call   0x2f38b3
   6:	85 ed                	test   %ebp,%ebp
   8:	0f 85 db 0c 00 00    	jne    0xce9
   e:	e8 f0 34 2f 00       	call   0x2f3503
  13:	48 89 1c 24          	mov    %rbx,(%rsp)
  17:	49 8d af c0 01 00 00 	lea    0x1c0(%r15),%rbp
  1e:	48 89 e8             	mov    %rbp,%rax
  21:	48 c1 e8 03          	shr    $0x3,%rax
  25:	48 89 44 24 48       	mov    %rax,0x48(%rsp)
* 2a:	42 0f b6 04 28       	movzbl (%rax,%r13,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 05 0d 00 00    	jne    0xd3c
  37:	8b 5d 00             	mov    0x0(%rbp),%ebx
  3a:	89 de                	mov    %ebx,%esi
  3c:	81                   	.byte 0x81
  3d:	e6 00                	out    %al,$0x0
  3f:	80                   	.byte 0x80

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/12 20:01 linux-6.6.y c596736dadab d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan general protection fault in iomap_dio_bio_end_io
2026/01/15 15:17 linux-6.6.y c596736dadab d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in iomap_dio_bio_end_io
2026/01/12 20:56 linux-6.6.y c596736dadab d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in iomap_dio_bio_end_io
2026/01/12 20:54 linux-6.6.y c596736dadab d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in iomap_dio_bio_end_io
2026/01/12 13:04 linux-6.6.y c596736dadab d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in iomap_dio_bio_end_io
2026/01/12 07:07 linux-6.6.y c596736dadab d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in iomap_dio_bio_end_io
2026/01/12 06:58 linux-6.6.y c596736dadab d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in iomap_dio_bio_end_io
2026/01/12 06:55 linux-6.6.y c596736dadab d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in iomap_dio_bio_end_io
2026/01/12 06:55 linux-6.6.y c596736dadab d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in iomap_dio_bio_end_io
* Struck through repros no longer work on HEAD.