Hello,
syzbot found the following issue on:
HEAD commit:4fa640dc Merge tag 'vfio-v5.8-rc7' of git://github.com/awi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12c738a090
kernel config: https://syzkaller.appspot.com/x/.config?x=f87a5e4232fdb267
dashboard link: https://syzkaller.appspot.com/bug?extid=0c6da80218456f1edc36
compiler: gcc (GCC) 10.1.0-syz 20200507
userspace arch: i386
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14e2a43710
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13af00e890
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0c6da80218456f1ed...@syzkaller.appspotmail.com
INFO: task kworker/0:5:2530 blocked for more than 144 seconds.
Not tainted 5.8.0-rc6-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/0:5 D26496 2530 2 0x4000
Workqueue: events free_ipc
Call Trace:
context_switch kernel/sched/core.c:3458 [inline]
__schedule+0x91f/0x2250 kernel/sched/core.c:4215
schedule+0xd0/0x2a0 kernel/sched/core.c:4290
schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1884
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x163/0x260 kernel/sched/completion.c:138
__wait_rcu_gp+0x217/0x2d0 kernel/rcu/update.c:411
synchronize_rcu+0x10a/0x180 kernel/rcu/tree.c:3430
kern_unmount fs/namespace.c:3861 [inline]
kern_unmount+0x67/0xe0 fs/namespace.c:3856
free_ipc_ns ipc/namespace.c:123 [inline]
free_ipc+0xbe/0x1b0 ipc/namespace.c:141
process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
kthread+0x3b5/0x4a0 kernel/kthread.c:291
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293
INFO: task syz-executor643:6834 blocked for more than 144 seconds.
Not tainted 5.8.0-rc6-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor643 D24000 6834 6833 0xa0024002
Call Trace:
context_switch kernel/sched/core.c:3458 [inline]
__schedule+0x91f/0x2250 kernel/sched/core.c:4215
schedule+0xd0/0x2a0 kernel/sched/core.c:4290
schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1884
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x163/0x260 kernel/sched/completion.c:138
rcu_barrier+0x2d1/0x4a0 kernel/rcu/tree.c:3661
netdev_run_todo+0x100/0xac0 net/core/dev.c:9758
tun_detach drivers/net/tun.c:711 [inline]
tun_chr_close+0xf5/0x180 drivers/net/tun.c:3423
__fput+0x33c/0x880 fs/file_table.c:281
task_work_run+0xdd/0x190 kernel/task_work.c:135
exit_task_work include/linux/task_work.h:25 [inline]
do_exit+0xb72/0x2a40 kernel/exit.c:805
do_group_exit+0x125/0x310 kernel/exit.c:903
__do_sys_exit_group kernel/exit.c:914 [inline]
__se_sys_exit_group kernel/exit.c:912 [inline]
__ia32_sys_exit_group+0x3a/0x50 kernel/exit.c:912
do_syscall_32_irqs_on+0x3f/0x60 arch/x86/entry/common.c:428
__do_fast_syscall_32 arch/x86/entry/common.c:475 [inline]
do_fast_syscall_32+0x7f/0x120 arch/x86/entry/common.c:503
entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7fef569
Code: Bad RIP value.
RSP: 002b:ffdacd8c EFLAGS: 0292 ORIG_RAX: 00fc
RAX: ffda RBX: 0001 RCX: 080f7b38
RDX: RSI: 080dffbc RDI: 080f7b40
RBP: 0001 R08: R09:
R10: R11: R12:
R13: R14: R15:
Showing all locks held in the system:
1 lock held by khungtaskd/1155:
#0: 89bc11c0 (rcu_read_lock){}-{1:2}, at:
debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779
2 locks held by kworker/0:5/2530:
#0: 8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at:
arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: 8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic64_set
include/asm-generic/atomic-instrumented.h:856 [inline]
#0: 8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set
include/asm-generic/atomic-long.h:41 [inline]
#0: 8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data
kernel/workqueue.c:616 [inline]
#0: 8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at:
set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
#0: 8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at:
process_one_work+0x82b/0x1670 kernel/workqueue.c:2240
#1: c9000804fda8 (free_ipc_work){+.+.}-{0:0}, at:
process_one_work+0x85f/0x1670 kernel/workqueue.c:2244
1 lock held by in:imklog/6529:
#0: 88809f8eadf0 (>f_pos_lock){+.+.}-{3:3}, at:
