rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (1 GPs behind) idle=581/1/0x4000000000000000 softirq=16829/16834 fqs=1 (t=10500 jiffies g=18565 q=172) rcu: rcu_preempt kthread starved for 8454 jiffies! g18565 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:28760 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4969 [inline] __schedule+0xa5a/0x48f0 kernel/sched/core.c:6250 schedule+0xd2/0x260 kernel/sched/core.c:6323 schedule_timeout+0x11d/0x250 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1955 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2128 kthread+0x3ab/0x480 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 9112 Comm: kworker/u4:7 Not tainted 5.15.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline] RIP: 0010:smp_call_function_many_cond+0x22e/0x9d0 kernel/smp.c:969 Code: 38 d0 7c 08 84 d2 0f 85 2b 05 00 00 8b 43 08 a8 01 74 2e 48 89 ca 49 89 cf 48 c1 ea 03 41 83 e7 07 4c 01 e2 41 83 c7 03 f3 90 <0f> b6 02 41 38 c7 7c 08 84 c0 0f 85 d4 04 00 00 8b 43 08 a8 01 75 RSP: 0018:ffffc9000d00fa60 EFLAGS: 00000202 RAX: 0000000000000011 RBX: ffff8880b9f3fc00 RCX: ffff8880b9f3fc08 RDX: ffffed10173e7f81 RSI: ffff8880b9e3ab08 RDI: ffffffff8a5f08a8 RBP: ffff8880b9e3ab00 R08: 0000000000000001 R09: ffffffff8edd1a07 R10: 0000000000000001 R11: 0000000000000000 R12: dffffc0000000000 R13: ffff8880b9e3ab08 R14: ffffed10173c7560 R15: 0000000000000003 FS: 0000000000000000(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f4c9c03e148 CR3: 000000000a88e000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x70 kernel/smp.c:1135 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:1112 [inline] text_poke_bp_batch+0x1b5/0x540 arch/x86/kernel/alternative.c:1297 text_poke_flush arch/x86/kernel/alternative.c:1451 [inline] text_poke_flush arch/x86/kernel/alternative.c:1448 [inline] text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1458 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x15f/0x220 kernel/jump_label.c:177 static_key_enable+0x11/0x20 kernel/jump_label.c:190 toggle_allocation_gate mm/kfence/core.c:732 [inline] toggle_allocation_gate+0xe3/0x310 mm/kfence/core.c:724 process_one_work+0x85b/0x1430 kernel/workqueue.c:2298 worker_thread+0x598/0x1040 kernel/workqueue.c:2445 kthread+0x3ab/0x480 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 NMI backtrace for cpu 1 CPU: 1 PID: 9841 Comm: syz-executor175 Not tainted 5.15.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x57/0x7d lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x30/0xc0 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x18a/0x1c0 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:627 [inline] check_cpu_stall kernel/rcu/tree_stall.h:711 [inline] rcu_pending kernel/rcu/tree.c:3878 [inline] rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2597 update_process_times+0x13b/0x1c0 kernel/time/timer.c:1785 tick_sched_handle+0x6f/0x130 kernel/time/tick-sched.c:226 tick_sched_timer+0x132/0x210 kernel/time/tick-sched.c:1421 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x18a/0xb00 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x2f5/0x780 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202 Code: 0f 1f 44 00 00 55 48 8b 74 24 08 48 89 fd 48 83 c7 18 e8 be ab e4 f8 48 89 ef e8 06 22 e5 f8 e8 51 8f 01 f9 fb bf 01 00 00 00 86 ff d7 f8 65 8b 05 af c7 92 77 85 c0 74 02 5d c3 0f 1f 44 00 RSP: 0018:ffffc90001b2f0a0 EFLAGS: 00000202 RAX: 00000000008c3823 RBX: ffff88806a9eaca8 RCX: 1ffffffff1dc174e RDX: 0000000000000000 RSI: ffffffff88cb4d00 RDI: 0000000000000001 RBP: ffff88806a9eacb0 R08: 0000000000000001 R09: ffffffff8edd1a9f R10: 0000000000000001 R11: 0000000000000001 R12: ffffc90001b2f120 R13: 0000000000000000 R14: fffff94000b40778 R15: dffffc0000000000 spin_unlock_irq include/linux/spinlock.h:399 [inline] __filemap_add_folio+0x479/0xa70 mm/filemap.c:952 filemap_add_folio+0xa7/0x170 mm/filemap.c:999 __filemap_get_folio+0x274/0x940 mm/filemap.c:1962 pagecache_get_page+0x10/0x100 mm/folio-compat.c:125 ext4_write_begin+0x228/0xff0 fs/ext4/inode.c:1174 ext4_da_write_begin+0x468/0x840 fs/ext4/inode.c:2941 generic_perform_write+0x1c7/0x440 mm/filemap.c:3756 ext4_buffered_write_iter+0x171/0x330 fs/ext4/file.c:269 ext4_file_write_iter+0x383/0x1160 fs/ext4/file.c:681 call_write_iter include/linux/fs.h:2162 [inline] do_iter_readv_writev+0x336/0x6d0 fs/read_write.c:725 do_iter_write+0x12a/0x620 fs/read_write.c:851 iter_file_splice_write+0x598/0xaf0 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0xfb/0x1c0 fs/splice.c:936 splice_direct_to_actor+0x2dd/0x7c0 fs/splice.c:891 do_splice_direct+0x154/0x260 fs/splice.c:979 do_sendfile+0x91e/0x1110 fs/read_write.c:1245 __do_sys_sendfile64 fs/read_write.c:1310 [inline] __se_sys_sendfile64 fs/read_write.c:1296 [inline] __x64_sys_sendfile64+0x186/0x1d0 fs/read_write.c:1296 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f5d58822149 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 14 00 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffdd2cb44f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 00007f5d58822149 RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000004 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001 R10: 00008400fffffffb R11: 0000000000000246 R12: 00007f5d587e5920 R13: 0000000000000000 R14: 00007ffdd2cb4520 R15: 00007ffdd2cb4510 ---------------- Code disassembly (best guess): 0: 38 d0 cmp %dl,%al 2: 7c 08 jl 0xc 4: 84 d2 test %dl,%dl 6: 0f 85 2b 05 00 00 jne 0x537 c: 8b 43 08 mov 0x8(%rbx),%eax f: a8 01 test $0x1,%al 11: 74 2e je 0x41 13: 48 89 ca mov %rcx,%rdx 16: 49 89 cf mov %rcx,%r15 19: 48 c1 ea 03 shr $0x3,%rdx 1d: 41 83 e7 07 and $0x7,%r15d 21: 4c 01 e2 add %r12,%rdx 24: 41 83 c7 03 add $0x3,%r15d 28: f3 90 pause * 2a: 0f b6 02 movzbl (%rdx),%eax <-- trapping instruction 2d: 41 38 c7 cmp %al,%r15b 30: 7c 08 jl 0x3a 32: 84 c0 test %al,%al 34: 0f 85 d4 04 00 00 jne 0x50e 3a: 8b 43 08 mov 0x8(%rbx),%eax 3d: a8 01 test $0x1,%al 3f: 75 .byte 0x75