linux-kernel - Re: [syzbot] [hfs?] kernel BUG in hfs_write

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Message-ID: <68dea8c7.050a0220.25d7ab.07ce.GAE@google.com>
Date: Thu, 02 Oct 2025 09:31:03 -0700
From: syzbot <syzbot+97e301b4b82ae803d21b@...kaller.appspotmail.com>
To: contact@...rnon.com, damien.lemoal@...nsource.wdc.com, jlayton@...nel.org, 
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com, willy@...radead.org
Subject: Re: [syzbot] [hfs?] kernel BUG in hfs_write_inode

Hello,

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

------------[ cut here ]------------
kernel BUG at fs/hfs/inode.c:444!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 1438 Comm: kworker/u8:9 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: writeback wb_workfn (flush-7:0)
RIP: 0010:hfs_write_inode+0x7c8/0x7d0 fs/hfs/inode.c:444
Code: c1 40 c2 05 99 80 e1 07 80 c1 03 38 c1 0f 8c 7d fe ff ff 48 c7 c7 40 c2 05 99 e8 e3 dc 8c ff e9 6c fe ff ff e8 a9 96 2d ff 90 <0f> 0b 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000534f180 EFLAGS: 00010293
RAX: ffffffff8290d517 RBX: ffff8880323301c8 RCX: ffff88802787d940
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000534f310 R08: ffff88802787d940 R09: 0000000000000003
R10: 0000000000000100 R11: 0000000000000004 R12: dffffc0000000000
R13: 1ffff92000a69e34 R14: ffff888032330188 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881269bc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff2f4ecb000 CR3: 0000000036660000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 write_inode fs/fs-writeback.c:1525 [inline]
 __writeback_single_inode+0x6f1/0x1000 fs/fs-writeback.c:1745
 writeback_sb_inodes+0x6b7/0xf60 fs/fs-writeback.c:1976
 wb_writeback+0x43b/0xaf0 fs/fs-writeback.c:2156
 wb_do_writeback fs/fs-writeback.c:2303 [inline]
 wb_workfn+0x40e/0xf00 fs/fs-writeback.c:2343
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x436/0x7d0 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:hfs_write_inode+0x7c8/0x7d0 fs/hfs/inode.c:444
Code: c1 40 c2 05 99 80 e1 07 80 c1 03 38 c1 0f 8c 7d fe ff ff 48 c7 c7 40 c2 05 99 e8 e3 dc 8c ff e9 6c fe ff ff e8 a9 96 2d ff 90 <0f> 0b 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000534f180 EFLAGS: 00010293
RAX: ffffffff8290d517 RBX: ffff8880323301c8 RCX: ffff88802787d940
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000534f310 R08: ffff88802787d940 R09: 0000000000000003
R10: 0000000000000100 R11: 0000000000000004 R12: dffffc0000000000
R13: 1ffff92000a69e34 R14: ffff888032330188 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881269bc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff2f4ecb000 CR3: 0000000036660000 CR4: 00000000003526f0


Tested on:

commit:         e5f0a698 Linux 6.17
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git v6.17
console output: https://syzkaller.appspot.com/x/log.txt?x=13b28458580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f5b21423ca3f0a96
dashboard link: https://syzkaller.appspot.com/bug?extid=97e301b4b82ae803d21b
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

Note: no patches were applied.