rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10499 ticks this GP) idle=416/1/0x4000000000000002 softirq=10670/10670 fqs=13 (t=10501 jiffies g=6933 q=131) rcu: rcu_preempt kthread starved for 10474 jiffies! g6933 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29032 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x9a0/0xcc0 kernel/sched/core.c:4081 schedule+0x181/0x210 kernel/sched/core.c:4155 schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline] rcu_gp_kthread+0xed8/0x1770 kernel/rcu/tree.c:1821 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 NMI backtrace for cpu 0 CPU: 0 PID: 8379 Comm: syz-executor.2 Not tainted 5.4.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fb/0x318 lib/dump_stack.c:118 nmi_cpu_backtrace+0xaf/0x1a0 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x174/0x290 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x15a/0x220 kernel/rcu/tree_stall.h:254 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline] check_cpu_stall kernel/rcu/tree_stall.h:529 [inline] rcu_pending kernel/rcu/tree.c:2827 [inline] rcu_sched_clock_irq+0xe25/0x1ad0 kernel/rcu/tree.c:2271 update_process_times+0x12d/0x180 kernel/time/timer.c:1726 tick_sched_handle kernel/time/tick-sched.c:167 [inline] tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1310 __run_hrtimer kernel/time/hrtimer.c:1514 [inline] __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1638 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:free_thread_stack+0x133/0x590 kernel/fork.c:280 Code: 00 ea ff ff 48 01 c7 be 03 00 00 00 e8 06 a2 60 00 e9 5d 04 00 00 e8 5c 2d 2e 00 48 89 df 31 f6 e8 42 af 6e 00 43 80 3c 2e 00 <74> 08 4c 89 e7 e8 43 a4 69 00 49 8b 1c 24 48 83 c3 08 48 89 d8 48 RSP: 0018:ffffc90002a37948 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000001 RBX: ffffea0002715940 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffea0002715940 RBP: ffffc90002a37980 R08: dffffc0000000000 R09: fffffbfff120248a R10: fffffbfff120248a R11: 0000000000000000 R12: ffff88808bba96a0 R13: dffffc0000000000 R14: 1ffff110117752d4 R15: ffff8880a6c799e8 release_task_stack kernel/fork.c:440 [inline] put_task_stack+0xa3/0x130 kernel/fork.c:451 finish_task_switch+0x3f1/0x550 kernel/sched/core.c:3256 context_switch kernel/sched/core.c:3388 [inline] __schedule+0x9a8/0xcc0 kernel/sched/core.c:4081 preempt_schedule_irq+0xc1/0x140 kernel/sched/core.c:4338 retint_kernel+0x1b/0x2b RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:752 [inline] RIP: 0010:lock_acquire+0x1b2/0x250 kernel/locking/lockdep.c:4488 Code: c1 e8 03 42 80 3c 30 00 74 0c 48 c7 c7 28 96 0a 89 e8 b2 7e 56 00 48 83 3d d2 01 af 07 00 0f 84 9c 00 00 00 48 8b 7d c0 57 9d <0f> 1f 44 00 00 48 83 c4 30 5b 41 5c 41 5d 41 5e 41 5f 5d c3 44 89 RSP: 0018:ffffc90002a37b98 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff12152c5 RBX: 0000000000000000 RCX: ffffffff815c6b62 RDX: dffffc0000000000 RSI: 0000000000000008 RDI: 0000000000000286 RBP: ffffc90002a37bf0 R08: dffffc0000000000 R09: fffffbfff13c8d1f R10: fffffbfff13c8d1f R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000000 R14: dffffc0000000000 R15: ffffffff890fe0f0 __fs_reclaim_acquire+0x24/0x30 mm/page_alloc.c:4084 fs_reclaim_acquire+0x5f/0xd0 mm/page_alloc.c:4095 slab_pre_alloc_hook mm/slab.h:562 [inline] slab_alloc mm/slab.c:3306 [inline] kmem_cache_alloc_trace+0x31/0x2f0 mm/slab.c:3549 kmalloc include/linux/slab.h:556 [inline] kzalloc include/linux/slab.h:670 [inline] smack_sk_alloc_security+0x10b/0x2c0 security/smack/smack_lsm.c:2249 security_sk_alloc+0x6c/0xd0 security/security.c:2069 sk_prot_alloc+0xd7/0x290 net/core/sock.c:1606 sk_alloc+0x38/0x9c0 net/core/sock.c:1657 unix_create1+0x91/0x560 net/unix/af_unix.c:771 unix_create+0x136/0x1c0 net/unix/af_unix.c:832 __sock_create+0x5cc/0x910 net/socket.c:1420 sock_create net/socket.c:1471 [inline] __sys_socket+0xe7/0x2e0 net/socket.c:1513 __do_sys_socket net/socket.c:1522 [inline] __se_sys_socket net/socket.c:1520 [inline] __x64_sys_socket+0x7a/0x90 net/socket.c:1520 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45d1c7 Code: 00 00 00 49 89 ca b8 36 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 4a 8b fb ff c3 66 0f 1f 84 00 00 00 00 00 b8 29 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 2d 8b fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffe186b6038 EFLAGS: 00000202 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 0000000000000010 RCX: 000000000045d1c7 RDX: 0000000000000000 RSI: 0000000000080002 RDI: 0000000000000001 RBP: 00000000004bfbf5 R08: 0000000000000000 R09: 0000000000000008 R10: 0000000000000078 R11: 0000000000000202 R12: 0000000000000003 R13: 0000000000000006 R14: 0000000000000000 R15: 00007ffe186b63c0