Message-ID: <6923a05a.a70a0220.2ea503.0075.GAE@google.com>
Date: Sun, 23 Nov 2025 16:01:30 -0800
From: syzbot <syzbot+a2b9a4ed0d61b1efb3f5@...kaller.appspotmail.com>
To: brauner@...nel.org, djwong@...nel.org, linux-fsdevel@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-xfs@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: [syzbot] [iomap?] general protection fault in iomap_dio_bio_end_io

Hello,

syzbot found the following issue on:

HEAD commit:    fe4d0dea039f Add linux-next specific files for 20251119
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=16bd7692580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f20a6db7594dcad7
dashboard link: https://syzkaller.appspot.com/bug?extid=a2b9a4ed0d61b1efb3f5
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12db68b4580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=107c0514580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ce4f26d91a01/disk-fe4d0dea.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6c9b53acf521/vmlinux-fe4d0dea.xz
kernel image: https://storage.googleapis.com/syzbot-assets/64d37d01cd64/bzImage-fe4d0dea.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/004457158842/mount_1.gz
  fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=133a1a12580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a2b9a4ed0d61b1efb3f5@...kaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000038: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x00000000000001c0-0x00000000000001c7]
CPU: 1 UID: 0 PID: 23 Comm: ksoftirqd/1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__queue_work+0xa4/0xf90 kernel/workqueue.c:2250
Code: 10 31 ff 89 ee e8 ac 24 37 00 85 ed 0f 85 9d 0c 00 00 e8 5f 20 37 00 4d 8d b5 c0 01 00 00 4c 89 f0 48 c1 e8 03 48 89 44 24 30 <0f> b6 04 18 84 c0 0f 85 c4 0c 00 00 4c 89 34 24 41 8b 2e 89 ee 81
RSP: 0018:ffffc900001d7868 EFLAGS: 00010002
RAX: 0000000000000038 RBX: dffffc0000000000 RCX: ffff88801d2d5b80
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff8880777ed647 R09: 1ffff1100eefdac8
R10: dffffc0000000000 R11: ffffed100eefdac9 R12: 0000000000000008
R13: 0000000000000000 R14: 00000000000001c0 R15: 0000000000000200
FS:  0000000000000000(0000) GS:ffff888125fbc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000073fc0000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 queue_work_on+0x181/0x270 kernel/workqueue.c:2386
 iomap_dio_bio_end_io+0xf4/0x1c0 fs/iomap/direct-io.c:222
 blk_update_request+0x57e/0xe60 block/blk-mq.c:1006
 blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1168
 blk_complete_reqs block/blk-mq.c:1243 [inline]
 blk_done_softirq+0x10a/0x160 block/blk-mq.c:1248
 handle_softirqs+0x27d/0x880 kernel/softirq.c:626
 run_ksoftirqd+0x9b/0x100 kernel/softirq.c:1067
 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__queue_work+0xa4/0xf90 kernel/workqueue.c:2250
Code: 10 31 ff 89 ee e8 ac 24 37 00 85 ed 0f 85 9d 0c 00 00 e8 5f 20 37 00 4d 8d b5 c0 01 00 00 4c 89 f0 48 c1 e8 03 48 89 44 24 30 <0f> b6 04 18 84 c0 0f 85 c4 0c 00 00 4c 89 34 24 41 8b 2e 89 ee 81
RSP: 0018:ffffc900001d7868 EFLAGS: 00010002
RAX: 0000000000000038 RBX: dffffc0000000000 RCX: ffff88801d2d5b80
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff8880777ed647 R09: 1ffff1100eefdac8
R10: dffffc0000000000 R11: ffffed100eefdac9 R12: 0000000000000008
R13: 0000000000000000 R14: 00000000000001c0 R15: 0000000000000200
FS:  0000000000000000(0000) GS:ffff888125fbc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000073fc0000 CR4: 00000000003526f0
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	31 ff                	xor    %edi,%edi
   2:	89 ee                	mov    %ebp,%esi
   4:	e8 ac 24 37 00       	call   0x3724b5
   9:	85 ed                	test   %ebp,%ebp
   b:	0f 85 9d 0c 00 00    	jne    0xcae
  11:	e8 5f 20 37 00       	call   0x372075
  16:	4d 8d b5 c0 01 00 00 	lea    0x1c0(%r13),%r14
  1d:	4c 89 f0             	mov    %r14,%rax
  20:	48 c1 e8 03          	shr    $0x3,%rax
  24:	48 89 44 24 30       	mov    %rax,0x30(%rsp)
* 29:	0f b6 04 18          	movzbl (%rax,%rbx,1),%eax <-- trapping instruction
  2d:	84 c0                	test   %al,%al
  2f:	0f 85 c4 0c 00 00    	jne    0xcf9
  35:	4c 89 34 24          	mov    %r14,(%rsp)
  39:	41 8b 2e             	mov    (%r14),%ebp
  3c:	89 ee                	mov    %ebp,%esi
  3e:	81                   	.byte 0x81


---
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