[Android 6.1] kernel BUG in ext4_split_extent_at (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: e2deb0b42a3a ANDROID: GKI: Update rockchip symbols for drm..
git tree: android14-6.1
console+strace: https://syzkaller.appspot.com/x/log.txt?x=171dfd82580000
kernel config: https://syzkaller.appspot.com/x/.config?x=5b6f08314e32b13d
dashboard link: https://syzkaller.appspot.com/bug?extid=2716ad6c543d92535dc2
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10e570f0580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15d6c7d4580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/685749cac4bf/disk-e2deb0b4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/19b5b0b9dbec/vmlinux-e2deb0b4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3f439b0190ca/bzImage-e2deb0b4.xz
mounted in repro #1: https://storage.googleapis.com/syzbot-assets/58c40bad3b4e/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=176570f0580000)
mounted in repro #2: https://storage.googleapis.com/syzbot-assets/19cb368afc74/mount_3.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=131dfd82580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2716ad...@syzkaller.appspotmail.com

------------[ cut here ]------------
kernel BUG at fs/ext4/extents.c:3186!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 304 Comm: syz-executor221 Not tainted 6.1.141-syzkaller-00038-ge2deb0b42a3a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:ext4_split_extent_at+0xf92/0xfb0 fs/ext4/extents.c:3186
Code: c9 fa ff ff 48 89 df 49 89 f7 e8 39 7c d0 ff 4c 89 fe e9 b6 fa ff ff e8 bc 22 8c ff 0f 0b e8 b5 22 8c ff 0f 0b e8 ae 22 8c ff <0f> 0b e8 a7 22 8c ff 0f 0b e8 a0 22 8c ff 0f 0b e8 99 22 8c ff 0f
RSP: 0018:ffffc90000ee7920 EFLAGS: 00010293
RAX: ffffffff81e3d4c2 RBX: 0000000000000010 RCX: ffff88810df79440
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000010
RBP: ffffc90000ee7a90 R08: 0000000000000000 R09: 0000000050000028
R10: ffffed1021df822a R11: 1ffff11021df8228 R12: ffff88810efc1100
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 00007f390a70d6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f250cd8d000 CR3: 000000012391f000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
ext4_force_split_extent_at fs/ext4/extents.c:338 [inline]
ext4_ext_remove_space+0x349d/0x3fb0 fs/ext4/extents.c:2880
ext4_punch_hole+0x77c/0xbd0 fs/ext4/inode.c:4141
ext4_fallocate+0x2b6/0x1dd0 fs/ext4/extents.c:4760
vfs_fallocate+0x4c5/0x5a0 fs/open.c:324
ksys_fallocate fs/open.c:347 [inline]
__do_sys_fallocate fs/open.c:355 [inline]
__se_sys_fallocate fs/open.c:353 [inline]
__x64_sys_fallocate+0xc0/0x110 fs/open.c:353
x64_sys_call+0x7fa/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:286
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f390a7508f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 81 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:00007f390a70d218 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f390a7e9608 RCX: 00007f390a7508f9
RDX: 0000000000000004 RSI: 0000000000000003 RDI: 0000000000000004
RBP: 00007f390a7e9600 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000010000 R11: 0000000000000246 R12: 00007f390a7b5b08
R13: 00007f390a7a40c0 R14: 0000200000010143 R15: 0000200000010140
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_split_extent_at+0xf92/0xfb0 fs/ext4/extents.c:3186
Code: c9 fa ff ff 48 89 df 49 89 f7 e8 39 7c d0 ff 4c 89 fe e9 b6 fa ff ff e8 bc 22 8c ff 0f 0b e8 b5 22 8c ff 0f 0b e8 ae 22 8c ff <0f> 0b e8 a7 22 8c ff 0f 0b e8 a0 22 8c ff 0f 0b e8 99 22 8c ff 0f
RSP: 0018:ffffc90000ee7920 EFLAGS: 00010293

RAX: ffffffff81e3d4c2 RBX: 0000000000000010 RCX: ffff88810df79440
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000010
RBP: ffffc90000ee7a90 R08: 0000000000000000 R09: 0000000050000028
R10: ffffed1021df822a R11: 1ffff11021df8228 R12: ffff88810efc1100
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 00007f390a70d6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f250cd8d000 CR3: 000000012391f000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
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[syzbot]

syzbot suspects this issue was fixed by commit:

commit 74088456b034ca0b32d45d270caae4dbb73e129e
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=17a20da2580000
start commit: e2deb0b42a3a ANDROID: GKI: Update rockchip symbols for drm..
git tree: android14-6.1

kernel config: https://syzkaller.appspot.com/x/.config?x=5b6f08314e32b13d
dashboard link: https://syzkaller.appspot.com/bug?extid=2716ad6c543d92535dc2

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10e570f0580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15d6c7d4580000

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