[v6.6] WARNING in ext4_iomap_begin

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: bb9c90ab9c5a Linux 6.6.102
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=13f34634580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7b989b97a0687b0a
dashboard link: https://syzkaller.appspot.com/bug?extid=374b2823c721a4f21fec
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/44e2224124c3/disk-bb9c90ab.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/33e0aef7ff42/vmlinux-bb9c90ab.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0515bc436228/bzImage-bb9c90ab.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+374b28...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 1 PID: 11782 at fs/ext4/inode.c:3388 ext4_iomap_begin+0x95f/0xad0 fs/ext4/inode.c:3388
Modules linked in:
CPU: 1 PID: 11782 Comm: syz.8.1506 Not tainted 6.6.102-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:ext4_iomap_begin+0x95f/0xad0 fs/ext4/inode.c:3388
Code: 3b 84 24 00 01 00 00 75 6d 44 89 f0 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 cb 5c 55 ff e9 77 ff ff ff e8 c1 5c 55 ff <0f> 0b 41 be de ff ff ff 49 bf 00 00 00 00 00 fc ff df eb 88 89 d9
RSP: 0018:ffffc900043af060 EFLAGS: 00010283
RAX: ffffffff82302e5f RBX: ffff888055ef838a RCX: 0000000000080000
RDX: ffffc9000c579000 RSI: 0000000000016c97 RDI: 0000000000016c98
RBP: ffffc900043af1b0 R08: ffff888055ef8057 R09: 1ffff1100abdf00a
R10: dffffc0000000000 R11: ffffed100abdf00b R12: 00000000000000d4
R13: 1ffff1100abdf071 R14: 000000000000000b R15: 0000000000000000
FS: 00007f013b9616c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f37df8659f0 CR3: 000000002dc98000 CR4: 00000000003506e0
Call Trace:
<TASK>
iomap_iter+0x6b1/0xec0 fs/iomap/iter.c:91
__iomap_dio_rw+0xb9c/0x1c40 fs/iomap/direct-io.c:658
iomap_dio_rw+0x45/0xa0 fs/iomap/direct-io.c:748
ext4_dio_write_iter fs/ext4/file.c:577 [inline]
ext4_file_write_iter+0x13ff/0x1870 fs/ext4/file.c:696
do_iter_readv_writev fs/read_write.c:-1 [inline]
do_iter_write+0x79a/0xc70 fs/read_write.c:860
iter_file_splice_write+0x66f/0xc50 fs/splice.c:736
do_splice_from fs/splice.c:933 [inline]
direct_splice_actor+0xe8/0x130 fs/splice.c:1142
splice_direct_to_actor+0x2f0/0x870 fs/splice.c:1088
do_splice_direct+0x1b7/0x2c0 fs/splice.c:1194
do_sendfile+0x5dc/0xf70 fs/read_write.c:1254
__do_sys_sendfile64 fs/read_write.c:1322 [inline]
__se_sys_sendfile64+0x13f/0x190 fs/read_write.c:1308
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f013ab8ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f013b961038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f013adb5fa0 RCX: 00007f013ab8ebe9
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000004
RBP: 00007f013ac11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020fffe82 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f013adb6038 R14: 00007f013adb5fa0 R15: 00007fff38cf5d68
</TASK>


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 0a805b6ea8cd Linux 6.6.116
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11de332f980000
kernel config: https://syzkaller.appspot.com/x/.config?x=12606d4b8832c7e4
dashboard link: https://syzkaller.appspot.com/bug?extid=374b2823c721a4f21fec
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=128fd812580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15031114580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/13874446b4b2/disk-0a805b6e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/69a5e59e1ade/vmlinux-0a805b6e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/322c0711f976/bzImage-0a805b6e.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/e4c67b6039f7/mount_0.gz
fsck result: OK (log: https://syzkaller.appspot.com/x/fsck.log?x=148fd812580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+374b28...@syzkaller.appspotmail.com

------------[ cut here ]------------

WARNING: CPU: 1 PID: 6220 at fs/ext4/inode.c:3388 ext4_iomap_begin+0x95f/0xad0 fs/ext4/inode.c:3388
Modules linked in:
CPU: 1 PID: 6220 Comm: syz.1.60 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025

RIP: 0010:ext4_iomap_begin+0x95f/0xad0 fs/ext4/inode.c:3388

Code: 3b 84 24 00 01 00 00 75 6d 44 89 f0 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 fb 50 55 ff e9 77 ff ff ff e8 f1 50 55 ff <0f> 0b 41 be de ff ff ff 49 bf 00 00 00 00 00 fc ff df eb 88 89 d9
RSP: 0018:ffffc900034a7640 EFLAGS: 00010293
RAX: ffffffff82303e9f RBX: ffff8880753eab8a RCX: ffff8880234d3c00
RDX: 0000000000000000 RSI: 00000000000000d4 RDI: 0000000000000000
RBP: ffffc900034a7790 R08: ffff8880753ea857 R09: 1ffff1100ea7d50a
R10: dffffc0000000000 R11: ffffed100ea7d50b R12: 00000000000000d4
R13: 1ffff1100ea7d571 R14: 000000000000000b R15: 0000000000000000
FS: 00007f4f73cad6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f26121156c0 CR3: 0000000030ba2000 CR4: 00000000003506e0

Call Trace:
<TASK>
iomap_iter+0x6b1/0xec0 fs/iomap/iter.c:91
__iomap_dio_rw+0xb9c/0x1c40 fs/iomap/direct-io.c:658
iomap_dio_rw+0x45/0xa0 fs/iomap/direct-io.c:748
ext4_dio_write_iter fs/ext4/file.c:577 [inline]
ext4_file_write_iter+0x13ff/0x1870 fs/ext4/file.c:696

call_write_iter include/linux/fs.h:2018 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x43b/0x940 fs/read_write.c:584
ksys_pwrite64 fs/read_write.c:699 [inline]
__do_sys_pwrite64 fs/read_write.c:709 [inline]
__se_sys_pwrite64 fs/read_write.c:706 [inline]
__x64_sys_pwrite64+0x195/0x220 fs/read_write.c:706

do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

RIP: 0033:0x7f4f72d8f6c9

Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48

RSP: 002b:00007f4f73cad038 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007f4f72fe5fa0 RCX: 00007f4f72d8f6c9
RDX: 00000000fffffd55 RSI: 0000200000000280 RDI: 0000000000000004
RBP: 00007f4f72e11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4f72fe6038 R14: 00007f4f72fe5fa0 R15: 00007ffd661cdea8
</TASK>


---
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