linux-kernel - [syzbot] [iomap?] WARNING in iomap

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Message-ID: <69777523.050a0220.1d05e9.0018.GAE@google.com>
Date: Mon, 26 Jan 2026 06:07:31 -0800
From: syzbot <syzbot+bd5ca596a01d01bfa083@...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?] WARNING in iomap_iter (6)

Hello,

syzbot found the following issue on:

HEAD commit:    a66191c590b3 Merge tag 'hyperv-fixes-signed-20260121' of g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10db3e3a580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=312c0a6c03e6d7df
dashboard link: https://syzkaller.appspot.com/bug?extid=bd5ca596a01d01bfa083
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
userspace arch: i386

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f802af648f7a/disk-a66191c5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9f28f489fe55/vmlinux-a66191c5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8c44005e0c3c/bzImage-a66191c5.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+bd5ca596a01d01bfa083@...kaller.appspotmail.com

------------[ cut here ]------------
iter->iomap.offset + iter->iomap.length <= iter->pos
WARNING: fs/iomap/iter.c:36 at iomap_iter_done fs/iomap/iter.c:36 [inline], CPU#0: kworker/u8:26/9724
WARNING: fs/iomap/iter.c:36 at iomap_iter+0x982/0xf30 fs/iomap/iter.c:114, CPU#0: kworker/u8:26/9724
Modules linked in:
CPU: 0 UID: 0 PID: 9724 Comm: kworker/u8:26 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
Workqueue: loop6 loop_workfn
RIP: 0010:iomap_iter_done fs/iomap/iter.c:36 [inline]
RIP: 0010:iomap_iter+0x982/0xf30 fs/iomap/iter.c:114
Code: ff ff ff e9 86 fa ff ff e8 ab 6d 65 ff 90 0f 0b 90 e9 06 fd ff ff e8 9d 6d 65 ff 90 0f 0b 90 e9 3b fd ff ff e8 8f 6d 65 ff 90 <0f> 0b 90 e9 97 fd ff ff e8 81 6d 65 ff 90 0f 0b 90 e9 c4 fd ff ff
RSP: 0018:ffffc9000cdcf268 EFLAGS: 00010293
RAX: ffffffff825d2b81 RBX: ffffc9000cdcf3c0 RCX: ffff88806e5d1e80
RDX: 0000000000000000 RSI: 8000000000083fff RDI: 0000003e80000000
RBP: ffffc9000cdcf3f8 R08: ffffc9000cdcf3e8 R09: ffffc9000cdcf430
R10: dffffc0000000000 R11: ffffffff8473db20 R12: 8000000000083fff
R13: ffffc9000cdcf402 R14: 1ffff920019b9e79 R15: 0000003e80000000
FS:  0000000000000000(0000) GS:ffff888125928000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000031712ff8 CR3: 0000000043618000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 iomap_file_buffered_write+0x275/0xa30 fs/iomap/buffered-io.c:1187
 blkdev_buffered_write block/fops.c:736 [inline]
 blkdev_write_iter+0x524/0x710 block/fops.c:802
 lo_rw_aio+0xc7a/0xf00 include/linux/percpu-rwsem.h:-1
 do_req_filebacked drivers/block/loop.c:434 [inline]
 loop_handle_cmd drivers/block/loop.c:1947 [inline]
 loop_process_work+0x61d/0x11a0 drivers/block/loop.c:1982
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340
 worker_thread+0x89f/0xd90 kernel/workqueue.c:3421
 kthread+0x726/0x8b0 kernel/kthread.c:463
 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>


---
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