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From: Eric Dumazet <edumazet@google.com>
Date: Fri, 5 Apr 2024 23:22:40 +0200
Message-ID: <CANn89iLxVgrd2QoFkv0xS6ppyZTyO5Hnv5+M5gGg99BQ09n5Ng@mail.gmail.com>
Subject: Re: [syzbot] [net?] WARNING in cleanup_net (3)
To: syzbot <syzbot+9ada62e1dc03fdc41982@syzkaller.appspotmail.com>
Cc: davem@davemloft.net, hdanton@sina.com, kuba@kernel.org, 
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, 
	syzkaller-bugs@googlegroups.com, xrivendell7@gmail.com
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On Fri, Apr 5, 2024 at 5:00=E2=80=AFAM syzbot
<syzbot+9ada62e1dc03fdc41982@syzkaller.appspotmail.com> wrote:
>
> syzbot has found a reproducer for the following issue on:
>
> HEAD commit:    fe46a7dd189e Merge tag 'sound-6.9-rc1' of git://git.kerne=
l..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=3D11fdccc518000=
0
> kernel config:  https://syzkaller.appspot.com/x/.config?x=3Dfe78468a74fdc=
3b7
> dashboard link: https://syzkaller.appspot.com/bug?extid=3D9ada62e1dc03fdc=
41982
> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Deb=
ian) 2.40
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=3D16696223180=
000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/0f7abe4afac7/dis=
k-fe46a7dd.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/82598d09246c/vmlinu=
x-fe46a7dd.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/efa23788c875/b=
zImage-fe46a7dd.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the comm=
it:
> Reported-by: syzbot+9ada62e1dc03fdc41982@syzkaller.appspotmail.com
>
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 5236 at lib/ref_tracker.c:179 ref_tracker_dir_exit+0=
x411/0x550 lib/ref_tracker.c:179
> Modules linked in:
> CPU: 1 PID: 5236 Comm: kworker/u8:6 Not tainted 6.8.0-syzkaller-08951-gfe=
46a7dd189e #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS G=
oogle 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 88 e7 9f 06 eb 1a e8 71 d2 b=
5 fc 48 8b 1c 24 48 89 df 48 8b 74 24 20 e8 70 e7 9f 06 90 <0f> 0b 90 48 83=
 c3 44 48 89 df be 04 00 00 00 e8 db 23 19 fd 48 89
> RSP: 0018:ffffc9000905f9e0 EFLAGS: 00010246
> RAX: 717a74f119e84f00 RBX: ffff888021ec9e98 RCX: 0000000000000001
> RDX: dffffc0000000000 RSI: ffffffff8baac1e0 RDI: 0000000000000001
> RBP: ffffc9000905fab0 R08: ffffffff92ce55ff R09: 1ffffffff259cabf
> R10: dffffc0000000000 R11: fffffbfff259cac0 R12: 1ffff1100df19ef8
> R13: dead000000000100 R14: ffff888021ec9ee8 R15: dffffc0000000000
> FS:  0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000=
000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f5c604d35c0 CR3: 0000000029078000 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>
>
>
> ---
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.

#syz fix: rds: tcp: Fix use-after-free of net in reqsk_timer_handler().