linux-kernel - Re: [syzbot] [f2fs?] kernel BUG in f2fs_write_end

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Message-ID: <68b550a2.a70a0220.1c57d1.0547.GAE@google.com>
Date: Mon, 01 Sep 2025 00:52:02 -0700
From: syzbot <syzbot+803dd716c4310d16ff3a@...kaller.appspotmail.com>
To: chao@...nel.org, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [f2fs?] kernel BUG in f2fs_write_end_io

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
kernel BUG in f2fs_write_end_io

------------[ cut here ]------------
kernel BUG at fs/f2fs/data.c:362!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 1159 Comm: kworker/u8:9 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:f2fs_write_end_io+0xb52/0xb60 fs/f2fs/data.c:361
Code: e8 33 f1 14 fe e9 91 f6 ff ff 89 d9 80 e1 07 38 c1 0f 8c e3 f6 ff ff 48 89 df e8 a9 f1 14 fe e9 d6 f6 ff ff e8 8f b4 b3 fd 90 <0f> 0b 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000007d38 EFLAGS: 00010246
RAX: ffffffff840bf6a1 RBX: 0000000000000000 RCX: ffff888027291e00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 000000000000000b
RBP: ffff8880744dd8c0 R08: ffffea0001685247 R09: 1ffffd40002d0a48
R10: dffffc0000000000 R11: fffff940002d0a49 R12: 0000000000000006
R13: ffffea0001685240 R14: 000000000000000b R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888125c54000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2aab608000 CR3: 0000000033b1a000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 blk_update_request+0x57e/0xe60 block/blk-mq.c:989
 blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1151
 blk_complete_reqs block/blk-mq.c:1226 [inline]
 blk_done_softirq+0x107/0x160 block/blk-mq.c:1231
 handle_softirqs+0x286/0x870 kernel/softirq.c:579
 do_softirq+0xec/0x180 kernel/softirq.c:480
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x17d/0x1c0 kernel/softirq.c:407
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:835 [inline]
 nsim_dev_trap_report_work+0x7c7/0xb80 drivers/net/netdevsim/dev.c:866
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:f2fs_write_end_io+0xb52/0xb60 fs/f2fs/data.c:361
Code: e8 33 f1 14 fe e9 91 f6 ff ff 89 d9 80 e1 07 38 c1 0f 8c e3 f6 ff ff 48 89 df e8 a9 f1 14 fe e9 d6 f6 ff ff e8 8f b4 b3 fd 90 <0f> 0b 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000007d38 EFLAGS: 00010246
RAX: ffffffff840bf6a1 RBX: 0000000000000000 RCX: ffff888027291e00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 000000000000000b
RBP: ffff8880744dd8c0 R08: ffffea0001685247 R09: 1ffffd40002d0a48
R10: dffffc0000000000 R11: fffff940002d0a49 R12: 0000000000000006
R13: ffffea0001685240 R14: 000000000000000b R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888125c54000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2aab608000 CR3: 0000000033b1a000 CR4: 00000000003526f0


Tested on:

commit:         e78352f9 f2fs: fix to do sanity check on node footer i..
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/chao/linux.git bugfix/syzbot
console output: https://syzkaller.appspot.com/x/log.txt?x=12306662580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4d8283cde63d6907
dashboard link: https://syzkaller.appspot.com/bug?extid=803dd716c4310d16ff3a
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

Note: no patches were applied.