rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P2970/1:b..l (detected by 0, t=10502 jiffies, g=241021, q=63) task:systemd-udevd state:R running task stack:20048 pid: 2970 ppid: 1 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb72/0x1460 kernel/sched/core.c:6287 preempt_schedule_common kernel/sched/core.c:6459 [inline] preempt_schedule+0x14d/0x190 kernel/sched/core.c:6484 preempt_schedule_thunk+0x16/0x18 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] _raw_spin_unlock_irqrestore+0x128/0x130 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:418 [inline] __wake_up_common_lock kernel/sched/wait.c:140 [inline] __wake_up_sync_key+0x124/0x1c0 kernel/sched/wait.c:205 sock_def_readable+0x106/0x200 net/core/sock.c:3054 __netlink_sendskb net/netlink/af_netlink.c:1266 [inline] netlink_sendskb+0x8d/0x130 net/netlink/af_netlink.c:1272 netlink_unicast+0x633/0x9f0 net/netlink/af_netlink.c:1360 netlink_sendmsg+0xa29/0xe50 net/netlink/af_netlink.c:1935 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg net/socket.c:724 [inline] ____sys_sendmsg+0x5b9/0x910 net/socket.c:2409 ___sys_sendmsg net/socket.c:2463 [inline] __sys_sendmsg+0x36f/0x450 net/socket.c:2492 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fa627dc7e67 RSP: 002b:00007ffdb35091b8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000055e3ec52c3a0 RCX: 00007fa627dc7e67 RDX: 0000000000000000 RSI: 00007ffdb35091d0 RDI: 0000000000000004 RBP: 00007ffdb35091d0 R08: 000055e3ec52d7a4 R09: 0000000000000000 R10: 0000000000000018 R11: 0000000000000246 R12: 000055e3ec521760 R13: 00000000000000a7 R14: 000055e3ec5323e0 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10497 jiffies! g241021 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 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:R running task stack:26544 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb72/0x1460 kernel/sched/core.c:6287 schedule+0x14b/0x210 kernel/sched/core.c:6366 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x1fd/0x770 kernel/rcu/tree.c:1957 rcu_gp_kthread+0xa5/0x350 kernel/rcu/tree.c:2130 kthread+0x453/0x480 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 28561 Comm: syz-executor.1 Not tainted 5.15.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:lockdep_recursion_finish kernel/locking/lockdep.c:438 [inline] RIP: 0010:lock_is_held_type+0x114/0x190 kernel/locking/lockdep.c:5669 Code: e0 03 31 db 44 39 f0 0f 94 c3 eb 05 bb 01 00 00 00 48 c7 c7 a0 05 4f 8a e8 09 11 00 00 b8 ff ff ff ff 65 0f c1 05 2c 6f 07 76 <83> f8 01 75 40 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 RSP: 0018:ffffc90000dc0a38 EFLAGS: 00000057 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000080010004 RDX: 0000000000000000 RSI: 0000000000010004 RDI: 0000000000000000 RBP: 0000000000000002 R08: dffffc0000000000 R09: ffffed10173a64a2 R10: ffffed10173a64a2 R11: 0000000000000000 R12: 0000000000000046 R13: ffff888051ad9c80 R14: 00000000ffffffff R15: ffffffff8c91c8e0 FS: 00007f81c56e5700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2cf22000 CR3: 000000004b731000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_is_held include/linux/lockdep.h:283 [inline] rcu_read_lock_sched_held+0x89/0x130 kernel/rcu/update.c:125 trace_lock_release+0x4f/0x150 include/trace/events/lock.h:58 lock_release+0x82/0x810 kernel/locking/lockdep.c:5636 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:158 [inline] _raw_spin_unlock_irqrestore+0x75/0x130 kernel/locking/spinlock.c:194 debug_hrtimer_deactivate kernel/time/hrtimer.c:425 [inline] debug_deactivate kernel/time/hrtimer.c:481 [inline] __run_hrtimer kernel/time/hrtimer.c:1653 [inline] __hrtimer_run_queues+0x2f9/0xa60 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0010:unwind_next_frame+0x41f/0x1fa0 arch/x86/kernel/unwind_orc.c:456 Code: 03 42 8a 04 30 84 c0 0f 85 08 16 00 00 c6 03 01 48 c7 c5 80 71 4b 8a 4c 8d 7d 04 48 8d 5d 05 4d 89 fc 49 c1 ec 03 43 8a 04 34 <84> c0 0f 85 8a 15 00 00 48 89 d8 48 c1 e8 03 42 8a 04 30 84 c0 0f RSP: 0018:ffffc90002d7f140 EFLAGS: 00000a02 RAX: 0000000000000000 RBX: ffffffff8ee2dbd3 RCX: ffffffff8e4a318c RDX: ffffffff8ee2dbc8 RSI: ffffffff8a000068 RDI: ffffffff813a1319 RBP: ffffffff8ee2dbce R08: 0000000000000012 R09: ffffc90002d7f2f0 R10: fffff520005afe4c R11: 0000000000000000 R12: 1ffffffff1dc5b7a R13: ffffffff8e4a3184 R14: dffffc0000000000 R15: ffffffff8ee2dbd2 arch_stack_walk+0x112/0x140 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x11b/0x1e0 kernel/stacktrace.c:121 kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc+0xdc/0x110 mm/kasan/common.c:513 kasan_kmalloc include/linux/kasan.h:264 [inline] kmem_cache_alloc_trace+0x9f/0x310 mm/slub.c:3240 kmalloc include/linux/slab.h:591 [inline] tty_alloc_file drivers/tty/tty_io.c:187 [inline] tty_open+0x9e3/0xdd0 drivers/tty/tty_io.c:2140 chrdev_open+0x5fb/0x680 fs/char_dev.c:414 do_dentry_open+0x7cb/0x1020 fs/open.c:822 do_open fs/namei.c:3428 [inline] path_openat+0x28b4/0x3670 fs/namei.c:3561 do_filp_open+0x277/0x4f0 fs/namei.c:3588 do_sys_openat2+0x13b/0x500 fs/open.c:1200 do_sys_open fs/open.c:1216 [inline] __do_sys_openat fs/open.c:1232 [inline] __se_sys_openat fs/open.c:1227 [inline] __x64_sys_openat+0x243/0x290 fs/open.c:1227 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f81c816fa39 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f81c56e5188 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f81c8272f60 RCX: 00007f81c816fa39 RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c RBP: 00007f81c81c9e8f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd111b39af R14: 00007f81c56e5300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: e0 03 loopne 0x5 2: 31 db xor %ebx,%ebx 4: 44 39 f0 cmp %r14d,%eax 7: 0f 94 c3 sete %bl a: eb 05 jmp 0x11 c: bb 01 00 00 00 mov $0x1,%ebx 11: 48 c7 c7 a0 05 4f 8a mov $0xffffffff8a4f05a0,%rdi 18: e8 09 11 00 00 callq 0x1126 1d: b8 ff ff ff ff mov $0xffffffff,%eax 22: 65 0f c1 05 2c 6f 07 xadd %eax,%gs:0x76076f2c(%rip) # 0x76076f56 29: 76 * 2a: 83 f8 01 cmp $0x1,%eax <-- trapping instruction 2d: 75 40 jne 0x6f 2f: 48 c7 04 24 00 00 00 movq $0x0,(%rsp) 36: 00 37: 9c pushfq 38: 8f 04 24 popq (%rsp) 3b: f7 .byte 0xf7 3c: 04 24 add $0x24,%al 3e: 00 02 add %al,(%rdx)