[v5.15] WARNING in ext4_iomap_begin

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 16fdf2c7111b Linux 5.15.181
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=13d97f74580000
kernel config: https://syzkaller.appspot.com/x/.config?x=1748ac0065c72647
dashboard link: https://syzkaller.appspot.com/bug?extid=8973d96aa456c9171655
compiler: Debian clang version 20.1.2 (++20250402124445+58df0ef89dd6-1~exp1~20250402004600.97), Debian LLD 20.1.2

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d8540163643f/disk-16fdf2c7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1a4c570bb8bc/vmlinux-16fdf2c7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d4ed683eba5e/bzImage-16fdf2c7.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8973d9...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 0 PID: 8132 at fs/ext4/inode.c:3436 ext4_iomap_begin+0xa0d/0xb80 fs/ext4/inode.c:3436
Modules linked in:
CPU: 0 PID: 8132 Comm: syz.7.904 Not tainted 5.15.181-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
RIP: 0010:ext4_iomap_begin+0xa0d/0xb80 fs/ext4/inode.c:3436
Code: 89 e8 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 37 f0 6e ff 48 bb 00 00 00 00 00 fc ff df e9 71 ff ff ff e8 23 f0 6e ff <0f> 0b 41 bd de ff ff ff 48 bb 00 00 00 00 00 fc ff df e9 7b ff ff
RSP: 0018:ffffc9000327efc0 EFLAGS: 00010287
RAX: ffffffff8208cded RBX: ffff88805c94bf3a RCX: 0000000000080000
RDX: ffffc90005d09000 RSI: 00000000000088d7 RDI: 00000000000088d8
RBP: ffffc9000327f140 R08: dffffc0000000000 R09: ffffed100b929785
R10: ffffed100b929785 R11: 1ffff1100b929784 R12: 00000000000000d4
R13: 1ffff1100b9297e7 R14: 000000000000000a R15: 0000000000000000
FS: 00007f34b139a6c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000011c030 CR3: 00000000798b4000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
iomap_iter+0x620/0xdb0 fs/iomap/iter.c:74
__iomap_dio_rw+0xa69/0x1a70 fs/iomap/direct-io.c:585
iomap_dio_rw+0x38/0x90 fs/iomap/direct-io.c:672
ext4_dio_write_iter fs/ext4/file.c:540 [inline]
ext4_file_write_iter+0x132b/0x17b0 fs/ext4/file.c:660
do_iter_readv_writev+0x497/0x600 fs/read_write.c:-1
do_iter_write+0x205/0x7b0 fs/read_write.c:855
iter_file_splice_write+0x65f/0xc40 fs/splice.c:689
do_splice_from fs/splice.c:767 [inline]
direct_splice_actor+0xe1/0x130 fs/splice.c:936
splice_direct_to_actor+0x4dc/0xb50 fs/splice.c:891
do_splice_direct+0x1b9/0x2c0 fs/splice.c:979
do_sendfile+0x5d5/0xec0 fs/read_write.c:1249
__do_sys_sendfile64 fs/read_write.c:1311 [inline]
__se_sys_sendfile64+0xd6/0x190 fs/read_write.c:1303
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f34b3553969
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:00007f34b139a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f34b377b080 RCX: 00007f34b3553969
RDX: 00002000000000c0 RSI: 0000000000000004 RDI: 0000000000000004
RBP: 00007f34b35d5ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000014000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f34b377b080 R15: 00007fff3675f2c8
</TASK>


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 16fdf2c7111b Linux 5.15.181
git tree: linux-5.15.y

console output: https://syzkaller.appspot.com/x/log.txt?x=13d9fa70580000

kernel config: https://syzkaller.appspot.com/x/.config?x=1748ac0065c72647
dashboard link: https://syzkaller.appspot.com/bug?extid=8973d96aa456c9171655
compiler: Debian clang version 20.1.2 (++20250402124445+58df0ef89dd6-1~exp1~20250402004600.97), Debian LLD 20.1.2

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=159aa8f4580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17d9fa70580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d8540163643f/disk-16fdf2c7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1a4c570bb8bc/vmlinux-16fdf2c7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d4ed683eba5e/bzImage-16fdf2c7.xz

mounted in repro: https://storage.googleapis.com/syzbot-assets/9b1e34a15948/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=11d284d4580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8973d9...@syzkaller.appspotmail.com

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

WARNING: CPU: 1 PID: 4221 at fs/ext4/inode.c:3436 ext4_iomap_begin+0xa0d/0xb80 fs/ext4/inode.c:3436
Modules linked in:
CPU: 1 PID: 4221 Comm: syz-executor231 Not tainted 5.15.181-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
RIP: 0010:ext4_iomap_begin+0xa0d/0xb80 fs/ext4/inode.c:3436
Code: 89 e8 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 37 f0 6e ff 48 bb 00 00 00 00 00 fc ff df e9 71 ff ff ff e8 23 f0 6e ff <0f> 0b 41 bd de ff ff ff 48 bb 00 00 00 00 00 fc ff df e9 7b ff ff

RSP: 0018:ffffc9000319f3c0 EFLAGS: 00010293
RAX: ffffffff8208cded RBX: ffff88806f06532a RCX: ffff888029eabb80
RDX: 0000000000000000 RSI: 00000000000000d4 RDI: 0000000000000000
RBP: ffffc9000319f540 R08: dffffc0000000000 R09: ffffed100de0ca03
R10: ffffed100de0ca03 R11: 1ffff1100de0ca02 R12: 00000000000000d4
R13: 1ffff1100de0ca65 R14: 000000000000000a R15: 0000000000000001
FS: 00007efc459596c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000

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

CR2: 000055557cc39738 CR3: 000000001f46e000 CR4: 00000000003506e0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
iomap_iter+0x620/0xdb0 fs/iomap/iter.c:74

__iomap_dio_rw+0x1014/0x1a70 fs/iomap/direct-io.c:585
iomap_dio_rw+0x38/0x90 fs/iomap/direct-io.c:672
ext4_dio_read_iter fs/ext4/file.c:77 [inline]
ext4_file_read_iter+0x573/0x700 fs/ext4/file.c:128
call_read_iter include/linux/fs.h:2166 [inline]
generic_file_splice_read+0x3a2/0x590 fs/splice.c:311
do_splice_to fs/splice.c:796 [inline]
splice_direct_to_actor+0x413/0xb50 fs/splice.c:870

do_splice_direct+0x1b9/0x2c0 fs/splice.c:979
do_sendfile+0x5d5/0xec0 fs/read_write.c:1249

__do_sys_sendfile64 fs/read_write.c:1317 [inline]
__se_sys_sendfile64+0x13b/0x190 fs/read_write.c:1303

do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0

RIP: 0033:0x7efc459bdcc9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 18 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007efc45959218 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007efc45a456d8 RCX: 00007efc459bdcc9
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000004
RBP: 00007efc45a456d0 R08: 00007ffea110eca7 R09: 0000000000000000
R10: 0000000000014000 R11: 0000000000000246 R12: 00007efc45a12590
R13: 0031656c69662f2e R14: 0000200000000600 R15: 0000003202000000
</TASK>


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

[syzbot]

syzbot suspects this issue was fixed by commit:

commit a597a609bfd4a2f6f4bce7b7d5f62769401c4c81
Author: Zhang Yi <yi.z...@huawei.com>
Date: Tue May 6 01:20:09 2025 +0000

ext4: ensure i_size is smaller than maxbytes

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=158f2d82580000
start commit: 16fdf2c7111b Linux 5.15.181
git tree: linux-5.15.y

kernel config: https://syzkaller.appspot.com/x/.config?x=1748ac0065c72647
dashboard link: https://syzkaller.appspot.com/bug?extid=8973d96aa456c9171655

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=135684f4580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14c0339b980000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: ext4: ensure i_size is smaller than maxbytes

For information about bisection process see: https://goo.gl/tpsmEJ#bisection