[Android 5.15] kernel BUG in ext4_ext_insert_extent

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b5b90d209864 Merge 5.15.198 into android13-5.15-lts
git tree: android13-5.15-lts
console output: https://syzkaller.appspot.com/x/log.txt?x=12f5165a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=deffac0a782f1cb0
dashboard link: https://syzkaller.appspot.com/bug?extid=2de0d91e23c76ff87bb3
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13d4b65a580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15342944580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e1f550806261/disk-b5b90d20.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7cf8ed0fef8a/vmlinux-b5b90d20.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1d3393e2f53b/bzImage-b5b90d20.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/15025789d8a9/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=15d4b65a580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2de0d9...@syzkaller.appspotmail.com

------------[ cut here ]------------
kernel BUG at fs/ext4/extents.c:2140!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 1506 Comm: syz.6.60 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:ext4_ext_insert_extent+0x477e/0x47c0 fs/ext4/extents.c:2140
Code: ff 44 89 f1 80 e1 07 fe c1 38 c1 0f 8c a5 e8 ff ff 4c 89 f7 e8 33 7b d4 ff e9 98 e8 ff ff e8 69 50 95 ff 0f 0b e8 62 50 95 ff <0f> 0b e8 5b 50 95 ff 0f 0b 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 19
RSP: 0018:ffffc90005166140 EFLAGS: 00010293
RAX: ffffffff81d47c4e RBX: ffff88812b2f0400 RCX: ffff8881118c93c0
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000006
RBP: ffffc900051662f0 R08: ffff888122547697 R09: 1ffff110244a8ed2
R10: dffffc0000000000 R11: ffffed10244a8ed3 R12: 0000000000000006
R13: ffff88812ef241a0 R14: ffff88812b2f043c R15: 0000000000000006
FS: 00007f89224a66c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffcc1eedd40 CR3: 0000000111f6d000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
ext4_ext_map_blocks+0x186c/0x61e0 fs/ext4/extents.c:4362
ext4_map_blocks+0x988/0x1b30 fs/ext4/inode.c:674
_ext4_get_block+0x1ea/0x540 fs/ext4/inode.c:817
ext4_get_block_unwritten+0x2a/0x40 fs/ext4/inode.c:848
ext4_block_write_begin+0x563/0x1160 fs/ext4/inode.c:1102
ext4_write_begin+0x65a/0x12e0 fs/ext4/ext4_jbd2.h:-1
ext4_da_write_begin+0x321/0xbf0 fs/ext4/inode.c:2988
generic_perform_write+0x2b7/0x690 mm/filemap.c:3870
ext4_buffered_write_iter+0x4ed/0x670 fs/ext4/file.c:270
ext4_file_write_iter+0x440/0x1540 fs/ext4/file.c:-1
__kernel_write+0x510/0x950 fs/read_write.c:539
__dump_emit+0x246/0x370 fs/coredump.c:880
dump_emit+0x383/0x3f0 fs/coredump.c:917
dump_user_range+0x86/0x1c0 fs/coredump.c:954
elf_core_dump+0x2a8f/0x2fd0 fs/binfmt_elf.c:2285
do_coredump+0x1452/0x2950 fs/coredump.c:831
get_signal+0x38d/0x1480 kernel/signal.c:2893
arch_do_signal_or_restart+0xdf/0x11c0 arch/x86/kernel/signal.c:867
handle_signal_work kernel/entry/common.c:154 [inline]
exit_to_user_mode_loop+0xa7/0xe0 kernel/entry/common.c:178
exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:214
irqentry_exit_to_user_mode+0x9/0x10 kernel/entry/common.c:320
irqentry_exit+0x12/0x40 kernel/entry/common.c:411
exc_page_fault+0x5e/0xb0 arch/x86/mm/fault.c:1568
asm_exc_page_fault+0x27/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7f8922641eb9
Code: Unable to access opcode bytes at RIP 0x7f8922641e8f.
RSP: 002b:00007f89224a5fd8 EFLAGS: 00010206
RAX: 0000000000000000 RBX: 00007f89228bcfa0 RCX: 00007f8922641eb9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000a000
RBP: 00007f89226afc1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f89228bd038 R14: 00007f89228bcfa0 R15: 00007ffcc1ef1308
</TASK>
Modules linked in:
---[ end trace 3731153fa4331a1f ]---
RIP: 0010:ext4_ext_insert_extent+0x477e/0x47c0 fs/ext4/extents.c:2140
Code: ff 44 89 f1 80 e1 07 fe c1 38 c1 0f 8c a5 e8 ff ff 4c 89 f7 e8 33 7b d4 ff e9 98 e8 ff ff e8 69 50 95 ff 0f 0b e8 62 50 95 ff <0f> 0b e8 5b 50 95 ff 0f 0b 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 19
RSP: 0018:ffffc90005166140 EFLAGS: 00010293
RAX: ffffffff81d47c4e RBX: ffff88812b2f0400 RCX: ffff8881118c93c0
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000006
RBP: ffffc900051662f0 R08: ffff888122547697 R09: 1ffff110244a8ed2
R10: dffffc0000000000 R11: ffffed10244a8ed3 R12: 0000000000000006
R13: ffff88812ef241a0 R14: ffff88812b2f043c R15: 0000000000000006
FS: 00007f89224a66c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8922641e8f CR3: 0000000111f6d000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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