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

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Message-ID: <69820c82.a00a0220.37c87e.0013.GAE@google.com>
Date: Tue, 03 Feb 2026 06:56:02 -0800
From: syzbot <syzbot+7de5fe447862fc37576f@...kaller.appspotmail.com>
To: kartikey406@...il.com, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [ext4?] kernel BUG in ext4_write_inline_data (4)

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
kernel BUG in ext4_write_inline_data

------------[ cut here ]------------
kernel BUG at fs/ext4/inline.c:240!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 1 UID: 0 PID: 7754 Comm: syz.0.172 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:ext4_write_inline_data+0x40b/0x4f0 fs/ext4/inline.c:240
Code: fe e8 69 6f 3f ff 42 8d 44 23 c4 bb 3c 00 00 00 89 44 24 08 44 29 e3 e9 aa fe ff ff e8 4e 6f 3f ff 90 0f 0b e8 46 6f 3f ff 90 <0f> 0b e8 3e 6f 3f ff 48 8d 3d f7 56 f6 0d 48 c7 c2 60 5b ac 8b 4c
RSP: 0018:ffffc9000c0574e0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000001000 RCX: ffffffff82c7691b
RDX: ffff888026555b80 RSI: ffffffff82c76b3a RDI: ffff888026555b80
RBP: ffff888077368298 R08: 0000000000000006 R09: 0000000000002000
R10: 000000000000003c R11: 0000000000000000 R12: 0000000000001000
R13: 0000000000002000 R14: ffffc9000c057580 R15: ffff888077368802
FS:  00007f86e72546c0(0000) GS:ffff8881246dc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f86e7211ff8 CR3: 000000007e6cf000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 ext4_write_inline_data_end+0x2a8/0xdb0 fs/ext4/inline.c:817
 ext4_da_write_end+0x4f7/0xf20 fs/ext4/inode.c:3286
 generic_perform_write+0x513/0xa40 mm/filemap.c:4335
 ext4_buffered_write_iter+0x119/0x440 fs/ext4/file.c:299
 ext4_file_write_iter+0xa3d/0x1d90 fs/ext4/file.c:723
 iter_file_splice_write+0x82b/0x10a0 fs/splice.c:738
 do_splice_from fs/splice.c:938 [inline]
 direct_splice_actor+0x192/0x6c0 fs/splice.c:1161
 splice_direct_to_actor+0x345/0xa30 fs/splice.c:1105
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0x174/0x240 fs/splice.c:1230
 do_sendfile+0xadc/0xe20 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1417
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f86e639aeb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f86e7254028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f86e6615fa0 RCX: 00007f86e639aeb9
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000004
RBP: 00007f86e6408c1f R08: 0000000000000000 R09: 0000000000000000
R10: 000000000e3aa6ea R11: 0000000000000246 R12: 0000000000000000
R13: 00007f86e6616038 R14: 00007f86e6615fa0 R15: 00007ffcedbd78f8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_write_inline_data+0x40b/0x4f0 fs/ext4/inline.c:240
Code: fe e8 69 6f 3f ff 42 8d 44 23 c4 bb 3c 00 00 00 89 44 24 08 44 29 e3 e9 aa fe ff ff e8 4e 6f 3f ff 90 0f 0b e8 46 6f 3f ff 90 <0f> 0b e8 3e 6f 3f ff 48 8d 3d f7 56 f6 0d 48 c7 c2 60 5b ac 8b 4c
RSP: 0018:ffffc9000c0574e0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000001000 RCX: ffffffff82c7691b
RDX: ffff888026555b80 RSI: ffffffff82c76b3a RDI: ffff888026555b80
RBP: ffff888077368298 R08: 0000000000000006 R09: 0000000000002000
R10: 000000000000003c R11: 0000000000000000 R12: 0000000000001000
R13: 0000000000002000 R14: ffffc9000c057580 R15: ffff888077368802
FS:  00007f86e72546c0(0000) GS:ffff8881246dc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffeb1036e30 CR3: 000000007e6cf000 CR4: 0000000000350ef0


Tested on:

commit:         6bd9ed02 Merge tag 'cgroup-for-6.19-rc8-fixes' of git:..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=162d7322580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=fea461e951c03b1b
dashboard link: https://syzkaller.appspot.com/bug?extid=7de5fe447862fc37576f
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1528c402580000