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rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [syzbot] WARNING in signalfd_cleanup Content-Language: en-US From: Pavel Begunkov To: Eric Biggers , Jens Axboe , io-uring@vger.kernel.org Cc: Eric Dumazet , syzbot , changbin.du@intel.com, Daniel Borkmann , David Miller , Heiner Kallweit , Jakub Kicinski , linux-fsdevel , LKML , netdev , syzkaller-bugs , Al Viro , Yajun Deng References: <000000000000c9a3fb05d4d787a3@google.com> <6a692d3e-2b8d-bef6-d54d-9880980b245c@gmail.com> In-Reply-To: <6a692d3e-2b8d-bef6-d54d-9880980b245c@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 1/5/22 17:37, Pavel Begunkov wrote: > On 1/5/22 15:52, Eric Biggers wrote: >> [+io_uring list and maintainers] >> >> This appears to be the known bug in io_uring where it doesn't POLLFREE >> notifications.  See previous discussion: >> https://lore.kernel.org/all/4a472e72-d527-db79-d46e-efa9d4cad5bb@kernel.dk/ > > We've got some fixing and groundwork done, but not POLLFREE yet. > Great to have a repro, thanks #syz test: https://github.com/isilence/linux.git pollfree_test1 Almost identical to how Eric did it for aio, let's try it out >> On Wed, Jan 05, 2022 at 07:42:10AM -0800, 'Eric Dumazet' via syzkaller-bugs wrote: >>> On Wed, Jan 5, 2022 at 7:37 AM syzbot >>> wrote: >>>> >>>> Hello, >>>> >>>> syzbot found the following issue on: >>>> >>>> HEAD commit:    6b8d4927540e Add linux-next specific files for 20220104 >>>> git tree:       linux-next >>>> console output: https://syzkaller.appspot.com/x/log.txt?x=159d88e3b00000 >>>> kernel config:  https://syzkaller.appspot.com/x/.config?x=45c9bbbf2ae8e3d3 >>>> dashboard link: https://syzkaller.appspot.com/bug?extid=5426c7ed6868c705ca14 >>>> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 >>>> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=117be65db00000 >>>> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15a75c8db00000 >>>> >>> >>> C repro looks legit, point to an io_uring issue. >>> >>>> The issue was bisected to: >>> >>> Please ignore the bisection. >>> >>>> >>>> commit e4b8954074f6d0db01c8c97d338a67f9389c042f >>>> Author: Eric Dumazet >>>> Date:   Tue Dec 7 01:30:37 2021 +0000 >>>> >>>>      netlink: add net device refcount tracker to struct ethnl_req_info >>>> >>>> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=12bca4e3b00000 >>>> final oops:     https://syzkaller.appspot.com/x/report.txt?x=11bca4e3b00000 >>>> console output: https://syzkaller.appspot.com/x/log.txt?x=16bca4e3b00000 >>>> >>>> IMPORTANT: if you fix the issue, please add the following tag to the commit: >>>> Reported-by: syzbot+5426c7ed6868c705ca14@syzkaller.appspotmail.com >>>> Fixes: e4b8954074f6 ("netlink: add net device refcount tracker to struct ethnl_req_info") >>>> >>>> ------------[ cut here ]------------ >>>> WARNING: CPU: 0 PID: 3604 at kernel/sched/wait.c:245 __wake_up_pollfree+0x40/0x50 kernel/sched/wait.c:246 >>>> Modules linked in: >>>> CPU: 0 PID: 3604 Comm: syz-executor714 Not tainted 5.16.0-rc8-next-20220104-syzkaller #0 >>>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 >>>> RIP: 0010:__wake_up_pollfree+0x40/0x50 kernel/sched/wait.c:245 >>>> Code: f3 ff ff 48 8d 6b 40 48 b8 00 00 00 00 00 fc ff df 48 89 ea 48 c1 ea 03 80 3c 02 00 75 11 48 8b 43 40 48 39 c5 75 03 5b 5d c3 <0f> 0b 5b 5d c3 48 89 ef e8 13 d8 69 00 eb e5 cc 48 c1 e7 06 48 63 >>>> RSP: 0018:ffffc90001aaf9f8 EFLAGS: 00010083 >>>> RAX: ffff88801cd623f0 RBX: ffff88801bec8048 RCX: 0000000000000000 >>>> RDX: 1ffff110037d9011 RSI: 0000000000000004 RDI: 0000000000000001 >>>> RBP: ffff88801bec8088 R08: 0000000000000000 R09: ffff88801bec804b >>>> R10: ffffed10037d9009 R11: 0000000000000000 R12: ffff88801bec8040 >>>> R13: ffff88801e029d40 R14: dffffc0000000000 R15: ffff88807eb50000 >>>> FS:  00005555573ad300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 >>>> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>>> CR2: 00000000200000c0 CR3: 000000001e5e4000 CR4: 00000000003506f0 >>>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >>>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >>>> Call Trace: >>>>   >>>>   wake_up_pollfree include/linux/wait.h:271 [inline] >>>>   signalfd_cleanup+0x42/0x60 fs/signalfd.c:38 >>>>   __cleanup_sighand kernel/fork.c:1596 [inline] >>>>   __cleanup_sighand+0x72/0xb0 kernel/fork.c:1593 >>>>   __exit_signal kernel/exit.c:159 [inline] >>>>   release_task+0xc02/0x17e0 kernel/exit.c:200 >>>>   wait_task_zombie kernel/exit.c:1117 [inline] >>>>   wait_consider_task+0x2fa6/0x3b80 kernel/exit.c:1344 >>>>   do_wait_thread kernel/exit.c:1407 [inline] >>>>   do_wait+0x6ca/0xce0 kernel/exit.c:1524 >>>>   kernel_wait4+0x14c/0x260 kernel/exit.c:1687 >>>>   __do_sys_wait4+0x13f/0x150 kernel/exit.c:1715 >>>>   do_syscall_x64 arch/x86/entry/common.c:50 [inline] >>>>   do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 >>>>   entry_SYSCALL_64_after_hwframe+0x44/0xae >>>> RIP: 0033:0x7facd6682386 >>>> Code: 0f 1f 40 00 31 c9 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 49 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 11 b8 3d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 5a c3 90 48 83 ec 28 89 54 24 14 48 89 74 24 >>>> RSP: 002b:00007ffdb91adef8 EFLAGS: 00000246 ORIG_RAX: 000000000000003d >>>> RAX: ffffffffffffffda RBX: 000000000000c646 RCX: 00007facd6682386 >>>> RDX: 0000000040000001 RSI: 00007ffdb91adf14 RDI: 00000000ffffffff >>>> RBP: 0000000000000f17 R08: 0000000000000032 R09: 00007ffdb91ec080 >>>> R10: 0000000000000000 R11: 0000000000000246 R12: 431bde82d7b634db >>>> R13: 00007ffdb91adf14 R14: 0000000000000000 R15: 0000000000000000 >>>>   >>>> >>>> >>>> --- >>>> This report is generated by a bot. It may contain errors. >>>> See https://goo.gl/tpsmEJ for more information about syzbot. >>>> syzbot engineers can be reached at syzkaller@googlegroups.com. >>>> >>>> syzbot will keep track of this issue. See: >>>> https://goo.gl/tpsmEJ#status for how to communicate with syzbot. >>>> For information about bisection process see: https://goo.gl/tpsmEJ#bisection >>>> syzbot can test patches for this issue, for details see: >>>> https://goo.gl/tpsmEJ#testing-patches >>> >>> -- >>> You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. >>> To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com. >>> To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/CANn89iK3tP3rANSWM7_%3DimMeMcUknT0U2GyfA9W4v12ad6_PkQ%40mail.gmail.com. > -- Pavel Begunkov