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Date: Sun, 07 Apr 2024 04:08:03 -0700
In-Reply-To: <20240407103306.1364-1-hdanton@sina.com>
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Subject: Re: [syzbot] [net?] WARNING in cleanup_net (3)
From: syzbot <syzbot+9ada62e1dc03fdc41982@syzkaller.appspotmail.com>
To: hdanton@sina.com, linux-kernel@vger.kernel.org, 
	syzkaller-bugs@googlegroups.com
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Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in cleanup_net

     __do_sys_unshare kernel/fork.c:3393 [inline]
     __se_sys_unshare kernel/fork.c:3391 [inline]
     __x64_sys_unshare+0x38/0x40 kernel/fork.c:3391
     do_syscall_64+0xfd/0x240
     entry_SYSCALL_64_after_hwframe+0x6d/0x75
------------[ cut here ]------------
WARNING: CPU: 1 PID: 1057 at lib/ref_tracker.c:179 ref_tracker_dir_exit+0x411/0x550 lib/ref_tracker.c:179
Modules linked in:
CPU: 1 PID: 1057 Comm: kworker/u8:7 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: netns cleanup_net
RIP: 0010:ref_tracker_dir_exit+0x411/0x550 lib/ref_tracker.c:179
Code: 48 8b 1c 24 48 89 df 48 8b 74 24 20 e8 08 e7 9f 06 eb 1a e8 f1 d1 b5 fc 48 8b 1c 24 48 89 df 48 8b 74 24 20 e8 f0 e6 9f 06 90 <0f> 0b 90 48 83 c3 44 48 89 df be 04 00 00 00 e8 5b 23 19 fd 48 89
RSP: 0018:ffffc90003c579e0 EFLAGS: 00010246
RAX: 75214a9c4e67f100 RBX: ffff88807a2b01d8 RCX: 0000000000000001
RDX: dffffc0000000000 RSI: ffffffff8baac1e0 RDI: 0000000000000001
RBP: ffffc90003c57ab0 R08: ffffffff92ce55ef R09: 1ffffffff259cabd
R10: dffffc0000000000 R11: fffffbfff259cabe R12: 1ffff1100fc58348
R13: dead000000000100 R14: ffff88807a2b0228 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f71ec36bfe4 CR3: 000000002dd64000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 net_free net/core/net_namespace.c:462 [inline]
 cleanup_net+0xbf3/0xcc0 net/core/net_namespace.c:658
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0xa02/0x1770 kernel/workqueue.c:3335
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
 kthread+0x2f2/0x390 kernel/kthread.c:388
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
 </TASK>


Tested on:

commit:         fe46a7dd Merge tag 'sound-6.9-rc1' of git://git.kernel..
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=16ad098d180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=fe78468a74fdc3b7
dashboard link: https://syzkaller.appspot.com/bug?extid=9ada62e1dc03fdc41982
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=165c53d3180000