linux-kernel - [syzbot] [ext4?] kernel BUG in ext4_write_inline

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Message-ID: <68c58bfa.050a0220.3c6139.04d2.GAE@google.com>
Date: Sat, 13 Sep 2025 08:21:30 -0700
From: syzbot <syzbot+f3185be57d7e8dda32b8@...kaller.appspotmail.com>
To: adilger.kernel@...ger.ca, linux-ext4@...r.kernel.org, 
	linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com, tytso@....edu
Subject: [syzbot] [ext4?] kernel BUG in ext4_write_inline_data (3)

Hello,

syzbot found the following issue on:

HEAD commit:    5f540c4aade9 Add linux-next specific files for 20250910
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=10025d62580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5ed48faa2cb8510d
dashboard link: https://syzkaller.appspot.com/bug?extid=f3185be57d7e8dda32b8
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/df0dfb072f52/disk-5f540c4a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/20649042ae30/vmlinux-5f540c4a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4c16358268b8/bzImage-5f540c4a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f3185be57d7e8dda32b8@...kaller.appspotmail.com

------------[ cut here ]------------
kernel BUG at fs/ext4/inline.c:240!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 28152 Comm: syz.8.5004 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:ext4_write_inline_data+0x43c/0x440 fs/ext4/inline.c:240
Code: c1 38 c1 0f 8c 19 ff ff ff 48 89 df 49 89 d7 e8 fa c8 b0 ff 4c 89 fa e9 06 ff ff ff e8 7d c2 4c ff 90 0f 0b e8 75 c2 4c ff 90 <0f> 0b 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f
RSP: 0018:ffffc900045273a8 EFLAGS: 00010287
RAX: ffffffff8272facb RBX: 0000000000003000 RCX: 0000000000080000
RDX: ffffc90016e08000 RSI: 0000000000001d1a RDI: 0000000000001d1b
RBP: ffff888012035472 R08: ffff88807cd4e387 R09: 1ffff1100f9a9c70
R10: dffffc0000000000 R11: ffffed100f9a9c71 R12: 000000000000003c
R13: ffffc90004527460 R14: 0000000000002000 R15: ffff888012034f18
FS:  00007f73a18866c0(0000) GS:ffff8881259f0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30511ff8 CR3: 0000000049be6000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 ext4_write_inline_data_end+0x336/0xab0 fs/ext4/inline.c:807
 generic_perform_write+0x627/0x900 mm/filemap.c:4230
 ext4_buffered_write_iter+0xce/0x3a0 fs/ext4/file.c:299
 ext4_file_write_iter+0x298/0x1bc0 fs/ext4/file.c:-1
 iter_file_splice_write+0x972/0x10e0 fs/splice.c:738
 do_splice_from fs/splice.c:938 [inline]
 direct_splice_actor+0xfe/0x160 fs/splice.c:1161
 splice_direct_to_actor+0x5a8/0xcc0 fs/splice.c:1105
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0x181/0x270 fs/splice.c:1230
 do_sendfile+0x4da/0x7e0 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64+0x13e/0x190 fs/read_write.c:1417
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f73a098eba9
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:00007f73a1886038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f73a0bd5fa0 RCX: 00007f73a098eba9
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000004
RBP: 00007f73a0a11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020fffe82 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f73a0bd6038 R14: 00007f73a0bd5fa0 R15: 00007ffcafa37c38
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_write_inline_data+0x43c/0x440 fs/ext4/inline.c:240
Code: c1 38 c1 0f 8c 19 ff ff ff 48 89 df 49 89 d7 e8 fa c8 b0 ff 4c 89 fa e9 06 ff ff ff e8 7d c2 4c ff 90 0f 0b e8 75 c2 4c ff 90 <0f> 0b 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f
RSP: 0018:ffffc900045273a8 EFLAGS: 00010287
RAX: ffffffff8272facb RBX: 0000000000003000 RCX: 0000000000080000
RDX: ffffc90016e08000 RSI: 0000000000001d1a RDI: 0000000000001d1b
RBP: ffff888012035472 R08: ffff88807cd4e387 R09: 1ffff1100f9a9c70
R10: dffffc0000000000 R11: ffffed100f9a9c71 R12: 000000000000003c
R13: ffffc90004527460 R14: 0000000000002000 R15: ffff888012034f18
FS:  00007f73a18866c0(0000) GS:ffff8881259f0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8fb8e97d58 CR3: 0000000049be6000 CR4: 00000000003526f0


---
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