linux-kernel - Re: [syzbot] [io-uring?] INFO: task hung in io_wq_put_and

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <67f1224b.050a0220.0a13.0239.GAE@google.com>
Date: Sat, 05 Apr 2025 05:30:03 -0700
From: syzbot <syzbot+58928048fd1416f1457c@...kaller.appspotmail.com>
To: asml.silence@...il.com, axboe@...nel.dk, io-uring@...r.kernel.org, 
	linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [io-uring?] INFO: task hung in io_wq_put_and_exit (4)

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
INFO: task hung in io_wq_put_and_exit

INFO: task syz.0.15:6739 blocked for more than 143 seconds.
      Not tainted 6.14.0-syzkaller-00001-g626e6212aaf6 #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.15        state:D stack:23744 pid:6739  tgid:6738  ppid:6553   task_flags:0x400548 flags:0x00024000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x18bc/0x4c40 kernel/sched/core.c:6765
 __schedule_loop kernel/sched/core.c:6842 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6857
 schedule_timeout+0xb0/0x290 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common kernel/sched/completion.c:127 [inline]
 wait_for_completion+0x355/0x620 kernel/sched/completion.c:148
 io_wq_exit_workers io_uring/io-wq.c:1262 [inline]
 io_wq_put_and_exit+0x344/0x720 io_uring/io-wq.c:1290
 io_uring_clean_tctx+0x168/0x1e0 io_uring/tctx.c:205
 io_uring_cancel_generic+0x751/0x800 io_uring/io_uring.c:3183
 io_uring_files_cancel include/linux/io_uring.h:19 [inline]
 do_exit+0x6a3/0x2940 kernel/exit.c:894
 do_group_exit+0x207/0x2c0 kernel/exit.c:1087
 get_signal+0x16b2/0x1750 kernel/signal.c:3036
 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2dc697e719
RSP: 002b:00007f2dc77490e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f2dc6b35f88 RCX: 00007f2dc697e719
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f2dc6b35f88
RBP: 00007f2dc6b35f80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2dc6b35f8c
R13: 0000000000000000 R14: 00007ffdb8b1f290 R15: 00007ffdb8b1f378
 </TASK>
INFO: task syz.4.19:6783 blocked for more than 146 seconds.
      Not tainted 6.14.0-syzkaller-00001-g626e6212aaf6 #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.19        state:D stack:25696 pid:6783  tgid:6779  ppid:6564   task_flags:0x400548 flags:0x00024000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x18bc/0x4c40 kernel/sched/core.c:6765
 __schedule_loop kernel/sched/core.c:6842 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6857
 schedule_timeout+0xb0/0x290 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common kernel/sched/completion.c:127 [inline]
 wait_for_completion+0x355/0x620 kernel/sched/completion.c:148
 io_wq_exit_workers io_uring/io-wq.c:1262 [inline]
 io_wq_put_and_exit+0x344/0x720 io_uring/io-wq.c:1290
 io_uring_clean_tctx+0x168/0x1e0 io_uring/tctx.c:205
 io_uring_cancel_generic+0x751/0x800 io_uring/io_uring.c:3183
 io_uring_files_cancel include/linux/io_uring.h:19 [inline]
 do_exit+0x6a3/0x2940 kernel/exit.c:894
 do_group_exit+0x207/0x2c0 kernel/exit.c:1087
 get_signal+0x16b2/0x1750 kernel/signal.c:3036
 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6cf337e719
RSP: 002b:00007f6cf40d00e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f6cf3535f88 RCX: 00007f6cf337e719
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f6cf3535f88
RBP: 00007f6cf3535f80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6cf3535f8c
R13: 0000000000000000 R14: 00007ffd41156d10 R15: 00007ffd41156df8
 </TASK>
INFO: task syz.2.17:6784 blocked for more than 148 seconds.
      Not tainted 6.14.0-syzkaller-00001-g626e6212aaf6 #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.17        state:D stack:23744 pid:6784  tgid:6780  ppid:6562   task_flags:0x400548 flags:0x00024000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x18bc/0x4c40 kernel/sched/core.c:6765
 __schedule_loop kernel/sched/core.c:6842 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6857
 schedule_timeout+0xb0/0x290 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common kernel/sched/completion.c:127 [inline]
 wait_for_completion+0x355/0x620 kernel/sched/completion.c:148
 io_wq_exit_workers io_uring/io-wq.c:1262 [inline]
 io_wq_put_and_exit+0x344/0x720 io_uring/io-wq.c:1290
 io_uring_clean_tctx+0x168/0x1e0 io_uring/tctx.c:205
 io_uring_cancel_generic+0x751/0x800 io_uring/io_uring.c:3183
 io_uring_files_cancel include/linux/io_uring.h:19 [inline]
 do_exit+0x6a3/0x2940 kernel/exit.c:894
 do_group_exit+0x207/0x2c0 kernel/exit.c:1087
 get_signal+0x16b2/0x1750 kernel/signal.c:3036
 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbb9517e719
RSP: 002b:00007fbb95f3b0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fbb95335f88 RCX: 00007fbb9517e719
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fbb95335f88
RBP: 00007fbb95335f80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fbb95335f8c
R13: 0000000000000000 R14: 00007ffc20ba6bf0 R15: 00007ffc20ba6cd8
 </TASK>
INFO: task syz.3.18:6820 blocked for more than 151 seconds.
      Not tainted 6.14.0-syzkaller-00001-g626e6212aaf6 #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.18        state:D stack:25184 pid:6820  tgid:6819  ppid:6563   task_flags:0x400548 flags:0x00024000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x18bc/0x4c40 kernel/sched/core.c:6765
 __schedule_loop kernel/sched/core.c:6842 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6857
 schedule_timeout+0xb0/0x290 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common kernel/sched/completion.c:127 [inline]
 wait_for_completion+0x355/0x620 kernel/sched/completion.c:148
 io_wq_exit_workers io_uring/io-wq.c:1262 [inline]
 io_wq_put_and_exit+0x344/0x720 io_uring/io-wq.c:1290
 io_uring_clean_tctx+0x168/0x1e0 io_uring/tctx.c:205
 io_uring_cancel_generic+0x751/0x800 io_uring/io_uring.c:3183
 io_uring_files_cancel include/linux/io_uring.h:19 [inline]
 do_exit+0x6a3/0x2940 kernel/exit.c:894


Tested on:

commit:         626e6212 io_uring/kbuf: conditional schedule on buffer..
git tree:       git://git.kernel.dk/linux.git syztest
console output: https://syzkaller.appspot.com/x/log.txt?x=105c9b4c580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a3f7ddbc4e0c74f1
dashboard link: https://syzkaller.appspot.com/bug?extid=58928048fd1416f1457c
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.