rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P11228/2:b..l rcu: (detected by 1, t=10502 jiffies, g=41105, q=2864862 ncpus=2) task:syz.1.1437 state:R running task stack:25768 pid:11228 tgid:11228 ppid:5598 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x1709/0x5530 kernel/sched/core.c:7231 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7553 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x8f0 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_acquire+0x231/0x350 kernel/locking/lockdep.c:5911 Code: ff ff ff e8 21 af a3 09 f7 44 24 10 00 02 00 00 0f 84 39 ff ff ff 65 48 8b 05 eb e9 fc 10 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 d0 7a a7 09 cc 48 8d 3d 28 cf 11 RSP: 0018:ffffc90006ba7a80 EFLAGS: 00000292 RAX: 8873af0346944300 RBX: 0000000000000001 RCX: 0000000000000046 RDX: ffffffff93522f90 RSI: ffffffff8daf031a RDI: ffffffff8bca7f80 RBP: ffff88801dad3e80 R08: 0000000000000008 R09: ffffffff95fd02f8 R10: 0000000098c681d0 R11: 00000000a395b18c R12: ffffffff8f8c9938 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000246 rt_spin_lock+0x83/0x400 kernel/locking/spinlock_rt.c:56 spin_lock include/linux/spinlock_rt.h:45 [inline] p9_pollwake+0x48/0x160 net/9p/trans_fd.c:499 __wake_up_common kernel/sched/wait.c:108 [inline] __wake_up_common_lock+0x13a/0x1f0 kernel/sched/wait.c:125 sock_def_wakeup+0x15e/0x270 net/core/sock.c:3631 unix_release_sock+0x793/0xd00 net/unix/af_unix.c:711 unix_release+0x92/0xd0 net/unix/af_unix.c:1182 __sock_release+0xa0/0x1f0 net/socket.c:739 sock_close+0x1c/0x30 net/socket.c:1541 __fput+0x42a/0xa80 fs/file_table.c:512 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:70 [inline] exit_to_user_mode_loop+0x1fa/0x730 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:316 [inline] do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f182cfbde59 RSP: 002b:00007fff84304ee8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f182d247da0 RCX: 00007f182cfbde59 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f182d247da0 R08: 0000000000000006 R09: 0000000000000000 R10: 00007f182d247cb0 R11: 0000000000000246 R12: 00000000000a5f79 R13: 00007f182d245fac R14: 00000000000a5c7b R15: 00007fff84304ff0 rcu: rcu_preempt kthread timer wakeup didn't happen for 7686 jiffies! g41105 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x1000 rcu: Possible timer handling issue on cpu=0 timer-softirq=28957 rcu: rcu_preempt kthread starved for 7687 jiffies! g41105 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x1000 ->cpu=0 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:D stack:27176 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000