rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10500 ticks this GP) idle=4d2/1/0x4000000000000000 softirq=254031/254031 fqs=90 (t=10500 jiffies g=438489 q=1156) rcu: rcu_preempt kthread starved for 10282 jiffies! g438489 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: rcu_preempt R running task 28480 10 2 0x00004000 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0x979/0xce0 kernel/sched/core.c:4527 NMI backtrace for cpu 0 CPU: 0 PID: 27751 Comm: syz-executor.1 Not tainted 5.8.0-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+0x1f0/0x31e lib/dump_stack.c:118 nmi_cpu_backtrace+0x9f/0x180 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x199/0x2a0 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+0x1920/0x1eb0 kernel/rcu/tree.c:2519 update_process_times+0x130/0x1b0 kernel/time/timer.c:1710 tick_sched_handle kernel/time/tick-sched.c:176 [inline] tick_sched_timer+0x25e/0x410 kernel/time/tick-sched.c:1328 __run_hrtimer kernel/time/hrtimer.c:1524 [inline] __hrtimer_run_queues+0x42d/0x930 kernel/time/hrtimer.c:1588 hrtimer_interrupt+0x373/0xd60 kernel/time/hrtimer.c:1650 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline] __sysvec_apic_timer_interrupt+0xf0/0x260 arch/x86/kernel/apic/apic.c:1097 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:50 [inline] sysvec_apic_timer_interrupt+0xd0/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline] RIP: 0010:_raw_spin_unlock_irq+0x57/0x80 kernel/locking/spinlock.c:199 Code: 00 00 00 00 fc ff df 80 3c 08 00 74 0c 48 c7 c7 c8 14 4d 89 e8 7a 18 8a f9 48 83 3d 0a 99 22 01 00 74 25 fb 66 0f 1f 44 00 00 01 00 00 00 e8 6f 52 26 f9 65 8b 05 34 82 d7 77 85 c0 74 02 5b RSP: 0018:ffffc90000007e10 EFLAGS: 00000286 RAX: 1ffffffff129a299 RBX: ffff8880ae825400 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff882a7b8f RBP: ffffc90000007f18 R08: dffffc0000000000 R09: fffffbfff167ccb6 R10: fffffbfff167ccb6 R11: 0000000000000000 R12: ffff888212370010 R13: dffffc0000000000 R14: ffff8880ae825400 R15: ffffffff868a9680 expire_timers kernel/time/timer.c:1457 [inline] __run_timers+0x64e/0x830 kernel/time/timer.c:1755 run_timer_softirq+0x46/0x80 kernel/time/timer.c:1768 __do_softirq+0x236/0x66c 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+0x91/0xe0 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:393 [inline] __irq_exit_rcu+0x1e1/0x1f0 kernel/softirq.c:423 irq_exit_rcu+0x5/0x10 kernel/softirq.c:435 sysvec_apic_timer_interrupt+0xd5/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:memset_erms+0xb/0x10 arch/x86/lib/memset_64.S:67 Code: 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 f3 aa <4c> 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 01 01 RSP: 0018:ffffc9001850f618 EFLAGS: 00000202 RAX: 1ffff920030a1e00 RBX: ffffc9001850f738 RCX: 0000000000000000 RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffffc9001850f748 RBP: ffffffff8a8c7f0e R08: dffffc0000000000 R09: ffffc9001850f738 R10: fffff520030a1ee9 R11: 0000000000000000 R12: 1ffffffff1518fe1 R13: ffffc9001850f6e8 R14: dffffc0000000000 R15: ffffffff8a8c7f0a unwind_next_frame+0x1122/0x1e90 arch/x86/kernel/unwind_orc.c:545 arch_stack_walk+0xb4/0xe0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xad/0x150 kernel/stacktrace.c:123 kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc+0x100/0x130 mm/kasan/common.c:461 slab_post_alloc_hook+0x3e/0x290 mm/slab.h:518 slab_alloc_node mm/slab.c:3254 [inline] kmem_cache_alloc_node+0x1e5/0x280 mm/slab.c:3574 __alloc_skb+0x94/0x4f0 net/core/skbuff.c:198 alloc_skb_fclone include/linux/skbuff.h:1135 [inline] sk_stream_alloc_skb+0x418/0xa60 net/ipv4/tcp.c:884 tcp_sendmsg_locked+0xe5c/0x3ed0 net/ipv4/tcp.c:1291 tcp_sendmsg+0x2c/0x40 net/ipv4/tcp.c:1441 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg net/socket.c:671 [inline] __sys_sendto+0x429/0x5c0 net/socket.c:1994 __do_sys_sendto net/socket.c:2006 [inline] __se_sys_sendto net/socket.c:2002 [inline] __x64_sys_sendto+0xda/0xf0 net/socket.c:2002 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45ce69 Code: 2d b6 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 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f3752f8ec78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 000000000002c380 RCX: 000000000045ce69 RDX: ffffffffffffffef RSI: 0000000020d7cfcb RDI: 0000000000000005 RBP: 000000000118bf78 R08: 0000000000000000 R09: 0000000009000000 R10: 0000000000000d80 R11: 0000000000000246 R12: 000000000118bf2c R13: 00007fffad77533f R14: 00007f3752f8f9c0 R15: 000000000118bf2c