rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (1 GPs behind) idle=6e6/1/0x4000000000000000 softirq=78452/78453 fqs=16 (t=10500 jiffies g=125925 q=382) rcu: rcu_preempt kthread starved for 10464 jiffies! g125925 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:29080 pid: 10 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0x8e5/0x21e0 kernel/sched/core.c:4527 schedule+0xd0/0x2a0 kernel/sched/core.c:4602 schedule_timeout+0x148/0x250 kernel/time/timer.c:1879 rcu_gp_fqs_loop kernel/rcu/tree.c:1888 [inline] rcu_gp_kthread+0xae5/0x1b50 kernel/rcu/tree.c:2058 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 NMI backtrace for cpu 0 CPU: 0 PID: 12529 Comm: syz-executor.0 Not tainted 5.9.0-rc1-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+0x18f/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x194/0x1cf kernel/rcu/tree_stall.h:318 print_cpu_stall kernel/rcu/tree_stall.h:551 [inline] check_cpu_stall kernel/rcu/tree_stall.h:625 [inline] rcu_pending kernel/rcu/tree.c:3637 [inline] rcu_sched_clock_irq.cold+0x5b3/0xccd kernel/rcu/tree.c:2519 update_process_times+0x25/0xa0 kernel/time/timer.c:1710 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176 tick_sched_timer+0x1d1/0x2a0 kernel/time/tick-sched.c:1328 __run_hrtimer kernel/time/hrtimer.c:1524 [inline] __hrtimer_run_queues+0x1d5/0xfc0 kernel/time/hrtimer.c:1588 hrtimer_interrupt+0x32a/0x930 kernel/time/hrtimer.c:1650 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline] __sysvec_apic_timer_interrupt+0x142/0x5e0 arch/x86/kernel/apic/apic.c:1097 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:50 [inline] sysvec_apic_timer_interrupt+0x4c/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:162 [inline] RIP: 0010:unwind_next_frame+0x278/0x1f90 arch/x86/kernel/unwind_orc.c:449 Code: 24 30 48 89 74 24 28 44 89 54 24 20 48 89 4c 24 18 e8 2c d4 80 00 4c 8b 44 24 30 48 8b 74 24 28 44 8b 54 24 20 48 8b 4c 24 18 <46> 8b 1c 85 50 1e a0 8b 44 8d 46 01 48 ba 00 00 00 00 00 fc ff df RSP: 0018:ffffc90000007790 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 1ffff92000000efa RCX: ffffffff87f2f09c RDX: 0000000000000003 RSI: 000000000006f2f0 RDI: ffffffff8bbbea10 RBP: 0000000000000001 R08: 000000000006f2f0 R09: 0000000000000000 R10: 000000000007201e R11: 0000000000000001 R12: ffffc900000078b0 R13: ffffc9000000789d R14: ffffc900000078b8 R15: ffffc90000007868 arch_stack_walk+0x81/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:123 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 __kmalloc_reserve net/core/skbuff.c:142 [inline] __alloc_skb+0xae/0x550 net/core/skbuff.c:210 alloc_skb include/linux/skbuff.h:1085 [inline] mrp_pdu_init net/802/mrp.c:300 [inline] mrp_pdu_append_vecattr_event+0x7b4/0x1020 net/802/mrp.c:399 mrp_attr_event+0x173/0x220 net/802/mrp.c:494 mrp_mad_event net/802/mrp.c:574 [inline] mrp_join_timer+0x5a/0xc0 net/802/mrp.c:591 call_timer_fn+0x1ac/0x760 kernel/time/timer.c:1413 expire_timers kernel/time/timer.c:1458 [inline] __run_timers.part.0+0x67c/0xaa0 kernel/time/timer.c:1755 __run_timers kernel/time/timer.c:1736 [inline] run_timer_softirq+0xae/0x1a0 kernel/time/timer.c:1768 __do_softirq+0x2de/0xa24 kernel/softirq.c:298 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline] do_softirq_own_stack+0x9d/0xd0 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:393 [inline] __irq_exit_rcu kernel/softirq.c:423 [inline] irq_exit_rcu+0x1f3/0x230 kernel/softirq.c:435 sysvec_apic_timer_interrupt+0x51/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:deref_stack_reg+0x15/0x150 arch/x86/kernel/unwind_orc.c:357 Code: 48 ff ff ff 48 89 0c 24 e8 f8 d7 80 00 48 8b 0c 24 eb 9d 66 90 48 b8 00 00 00 00 00 fc ff df 41 55 41 54 49 89 fc 55 48 89 f5 <53> 48 89 d3 48 89 fa 48 c1 ea 03 48 83 ec 08 0f b6 04 02 84 c0 74 RSP: 0018:ffffc900166ff868 EFLAGS: 00000287 RAX: dffffc0000000000 RBX: 1ffff92002cdff19 RCX: 0000000000000000 RDX: ffffc900166ff9a0 RSI: ffffc900166ffd00 RDI: ffffc900166ff960 RBP: ffffc900166ffd00 R08: ffffffff8b269a2e R09: 0000000000000001 R10: 000000000007201e R11: 0000000000000001 R12: ffffc900166ff960 R13: ffffc900166ff995 R14: ffffc900166ff9b0 R15: ffffc900166ff960 unwind_next_frame+0x12e5/0x1f90 arch/x86/kernel/unwind_orc.c:590 arch_stack_walk+0x81/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:123 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 slab_post_alloc_hook mm/slab.h:518 [inline] slab_alloc mm/slab.c:3312 [inline] kmem_cache_alloc+0x138/0x3a0 mm/slab.c:3482 __d_alloc+0x2a/0x950 fs/dcache.c:1709 d_alloc_pseudo+0x19/0x70 fs/dcache.c:1838 alloc_file_pseudo+0xc6/0x250 fs/file_table.c:226 sock_alloc_file+0x4f/0x190 net/socket.c:411 sock_map_fd net/socket.c:435 [inline] __sys_socket+0x13d/0x200 net/socket.c:1524 __do_sys_socket net/socket.c:1529 [inline] __se_sys_socket net/socket.c:1527 [inline] __x64_sys_socket+0x6f/0xb0 net/socket.c:1527 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d4d9 Code: 5d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f8f9b139c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 0000000000032cc0 RCX: 000000000045d4d9 RDX: 0000000000000084 RSI: 0000000000000005 RDI: 000000000000000a RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffc33023c9f R14: 00007f8f9b13a9c0 R15: 000000000118cf4c