rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=689/1/0x4000000000000000 softirq=98579/98579 fqs=2 (detected by 0, t=10502 jiffies, g=137173, q=170 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 16682 Comm: syz-executor.5 Not tainted 5.18.0-syzkaller-01850-gaa051d36ce4a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:check_wait_context kernel/locking/lockdep.c:4712 [inline] RIP: 0010:__lock_acquire+0x63d/0x1f80 kernel/locking/lockdep.c:4972 Code: ff cd 0f 88 9e 00 00 00 89 eb 83 fd 31 73 79 48 8d 04 9b 49 8d 9c c7 80 0a 00 00 48 89 d8 48 c1 e8 03 0f b6 04 10 84 c0 75 1d <8b> 1b 48 8b 44 24 20 0f b6 04 10 84 c0 75 2e 41 33 5d 00 f7 c3 00 RSP: 0018:ffffc900001e0a28 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffff88807be0c620 RCX: 0000000000000001 RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffffffff8fb2efc0 RBP: 0000000000000004 R08: dffffc0000000000 R09: fffffbfff1f65df9 R10: fffffbfff1f65df9 R11: 1ffffffff1f65df8 R12: 0000000000000005 R13: ffff88807be0c648 R14: ffff88807be0c558 R15: ffff88807be0bb00 FS: 00005555564ad400(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff26c0d53a5 CR3: 0000000027256000 CR4: 00000000003506e0 Call Trace: lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5634 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:269 rcu_read_lock include/linux/rcupdate.h:695 [inline] advance_sched+0x67e/0x8c0 net/sched/sch_taprio.c:768 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x50b/0xa60 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3a6/0xfd0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1095 [inline] __sysvec_apic_timer_interrupt+0xf9/0x280 arch/x86/kernel/apic/apic.c:1112 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1106 asm_sysvec_apic_timer_interrupt+0x1b/0x20 RIP: 0010:lock_acquire+0x21e/0x400 kernel/locking/lockdep.c:5638 Code: 23 00 74 08 4c 89 f7 e8 50 2a 70 00 f6 44 24 61 02 0f 85 76 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 04 2c 00 00 00 00 43 c7 44 2c 09 00 00 00 00 43 c7 44 2c 11 RSP: 0018:ffffc90002d2f6e0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff920005a5ee8 RCX: ffff88807be0c558 RDX: dffffc0000000000 RSI: ffffffff8a8d2ee0 RDI: ffffffff8ae90120 RBP: ffffc90002d2f828 R08: dffffc0000000000 R09: fffffbfff1f65dfb R10: fffffbfff1f65dfb R11: 1ffffffff1f65dfa R12: dffffc0000000000 R13: 1ffff920005a5ee4 R14: ffffc90002d2f740 R15: 0000000000000246 fs_reclaim_acquire+0xa6/0x120 mm/page_alloc.c:4589 might_alloc include/linux/sched/mm.h:262 [inline] slab_pre_alloc_hook mm/slab.h:722 [inline] slab_alloc_node mm/slub.c:3131 [inline] slab_alloc mm/slub.c:3225 [inline] __kmem_cache_alloc_lru mm/slub.c:3232 [inline] kmem_cache_alloc+0x3a/0x2f0 mm/slub.c:3242 anon_vma_chain_alloc mm/rmap.c:139 [inline] anon_vma_fork+0x1d0/0x540 mm/rmap.c:360 dup_mmap+0x77c/0xde0 kernel/fork.c:660 dup_mm+0x8c/0x310 kernel/fork.c:1526 copy_mm+0x102/0x190 kernel/fork.c:1578 copy_process+0x1856/0x3f70 kernel/fork.c:2239 kernel_clone+0x22f/0x7a0 kernel/fork.c:2644 __do_sys_clone kernel/fork.c:2761 [inline] __se_sys_clone kernel/fork.c:2745 [inline] __x64_sys_clone+0x289/0x310 kernel/fork.c:2745 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x7ff6b48876fb Code: ed 0f 85 60 01 00 00 64 4c 8b 0c 25 10 00 00 00 45 31 c0 4d 8d 91 d0 02 00 00 31 d2 31 f6 bf 11 00 20 01 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 89 00 00 00 41 89 c5 85 c0 0f 85 90 00 00 RSP: 002b:00007fff3974a3b0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff6b48876fb RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 00005555564ad400 R10: 00005555564ad6d0 R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000001 R15: 00007fff3974a490 rcu: rcu_preempt kthread timer wakeup didn't happen for 10489 jiffies! g137173 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=87073 rcu: rcu_preempt kthread starved for 10490 jiffies! g137173 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26424 pid: 16 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5076 [inline] __schedule+0x957/0xec0 kernel/sched/core.c:6391 schedule+0xeb/0x1b0 kernel/sched/core.c:6463 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1935 rcu_gp_fqs_loop+0x2b9/0xfb0 kernel/rcu/tree.c:1999 rcu_gp_kthread+0xa5/0x360 kernel/rcu/tree.c:2187 kthread+0x266/0x300 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 0 CPU: 0 PID: 3775 Comm: kworker/u4:10 Not tainted 5.18.0-syzkaller-01850-gaa051d36ce4a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound toggle_allocation_gate Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 nmi_cpu_backtrace+0x473/0x4a0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x168/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_check_gp_kthread_starvation+0x1da/0x250 kernel/rcu/tree_stall.h:518 print_other_cpu_stall+0x140a/0x1560 kernel/rcu/tree_stall.h:623 check_cpu_stall kernel/rcu/tree_stall.h:769 [inline] rcu_pending kernel/rcu/tree.c:3977 [inline] rcu_sched_clock_irq+0x9c4/0x19d0 kernel/rcu/tree.c:2675 update_process_times+0x148/0x1b0 kernel/time/timer.c:1839 tick_sched_handle kernel/time/tick-sched.c:243 [inline] tick_sched_timer+0x377/0x540 kernel/time/tick-sched.c:1481 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4cb/0xa60 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3a6/0xfd0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1095 [inline] __sysvec_apic_timer_interrupt+0xf9/0x280 arch/x86/kernel/apic/apic.c:1112 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1106 asm_sysvec_apic_timer_interrupt+0x1b/0x20 RIP: 0010:csd_lock_wait kernel/smp.c:414 [inline] RIP: 0010:smp_call_function_many_cond+0xf23/0x1500 kernel/smp.c:988 Code: 83 e7 01 49 bf 00 00 00 00 00 fc ff df 75 08 e8 e3 3e 0c 00 eb 46 90 f3 90 42 0f b6 04 3b 84 c0 75 11 41 f7 04 24 01 00 00 00 <74> 2b e8 c6 3e 0c 00 eb e4 44 89 e1 80 e1 07 80 c1 03 38 c1 7c e2 RSP: 0018:ffffc900042ef780 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 1ffff11017367fd9 RCX: ffff8880194a3b00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900042ef940 R08: ffffffff817a33a8 R09: fffffbfff1f65df9 R10: fffffbfff1f65df9 R11: 1ffffffff1f65df8 R12: ffff8880b9b3fec8 R13: 1ffff110173475a0 R14: 0000000000000001 R15: dffffc0000000000 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1154 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:1184 [inline] text_poke_bp_batch+0x31d/0x960 arch/x86/kernel/alternative.c:1372 text_poke_flush arch/x86/kernel/alternative.c:1542 [inline] text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1549 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x129/0x250 kernel/jump_label.c:177 static_key_enable+0x16/0x20 kernel/jump_label.c:190 toggle_allocation_gate+0xbf/0x470 mm/kfence/core.c:774 process_one_work+0x81c/0xd10 kernel/workqueue.c:2289 worker_thread+0xb14/0x1330 kernel/workqueue.c:2436 kthread+0x266/0x300 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 ---------------- Code disassembly (best guess): 0: ff cd dec %ebp 2: 0f 88 9e 00 00 00 js 0xa6 8: 89 eb mov %ebp,%ebx a: 83 fd 31 cmp $0x31,%ebp d: 73 79 jae 0x88 f: 48 8d 04 9b lea (%rbx,%rbx,4),%rax 13: 49 8d 9c c7 80 0a 00 lea 0xa80(%r15,%rax,8),%rbx 1a: 00 1b: 48 89 d8 mov %rbx,%rax 1e: 48 c1 e8 03 shr $0x3,%rax 22: 0f b6 04 10 movzbl (%rax,%rdx,1),%eax 26: 84 c0 test %al,%al 28: 75 1d jne 0x47 * 2a: 8b 1b mov (%rbx),%ebx <-- trapping instruction 2c: 48 8b 44 24 20 mov 0x20(%rsp),%rax 31: 0f b6 04 10 movzbl (%rax,%rdx,1),%eax 35: 84 c0 test %al,%al 37: 75 2e jne 0x67 39: 41 33 5d 00 xor 0x0(%r13),%ebx 3d: f7 .byte 0xf7 3e: c3 retq