rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=fa1c/1/0x4000000000000000 softirq=177792/177799 fqs=1 rcu: (detected by 1, t=10506 jiffies, g=154821, q=1784 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5170 Comm: syslogd Not tainted 6.13.0-rc7-syzkaller-00102-gce69b4019001 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline] RIP: 0010:rcu_is_watching+0x24/0xc0 kernel/rcu/tree.c:737 Code: 90 90 90 90 90 90 f3 0f 1e fa 55 53 65 ff 05 9b 29 84 7e e8 ce 70 aa 09 48 c7 c3 68 7f 03 00 83 f8 07 89 c5 0f 87 82 00 00 00 <48> 8d 3c ed e0 7c a7 8d 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 RSP: 0018:ffffc90000007c80 EFLAGS: 00000097 RAX: 0000000000000000 RBX: 0000000000037f68 RCX: ffffffff8175ee9c RDX: fffffbfff20be933 RSI: ffffffff8bd1eea0 RDI: ffffffff8bd1eee0 RBP: 0000000000000000 R08: 0000000000000000 R09: fffffbfff20be932 R10: ffffffff905f4997 R11: 0000000000000003 R12: 0000000000000000 R13: 000000000003d90c R14: 0000000000000001 R15: 0000000000000000 FS: 00007fba9d681500(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c3c35e9 CR3: 0000000035156000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: trace_lock_acquire+0x14e/0x1f0 include/trace/events/lock.h:24 lock_acquire+0x2f/0xb0 kernel/locking/lockdep.c:5820 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 debug_object_deactivate+0x13b/0x370 lib/debugobjects.c:873 debug_hrtimer_deactivate kernel/time/hrtimer.c:433 [inline] debug_deactivate kernel/time/hrtimer.c:475 [inline] __run_hrtimer kernel/time/hrtimer.c:1707 [inline] __hrtimer_run_queues+0x47c/0xae0 kernel/time/hrtimer.c:1803 hrtimer_interrupt+0x392/0x8e0 kernel/time/hrtimer.c:1865 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x10f/0x400 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:26 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0xc/0x70 kernel/kcov.c:217 Code: cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 65 48 8b 15 54 b4 69 7e <65> 8b 05 55 b4 69 7e a9 00 01 ff 00 48 8b 34 24 74 1d f6 c4 01 74 RSP: 0018:ffffc90004fefb18 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81db164c RDX: ffff888040e72440 RSI: 0000000000000000 RDI: 0000000000000005 RBP: ffff88801b7044f0 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000003 R12: 1ffff920009fdf67 R13: ffffc90004fefc60 R14: 0000000000000001 R15: ffff88801b7042d0 shmem_write_begin+0x1b7/0x300 mm/shmem.c:3124 generic_perform_write+0x2ba/0x920 mm/filemap.c:4046 shmem_file_write_iter+0x10e/0x140 mm/shmem.c:3296 new_sync_write fs/read_write.c:586 [inline] vfs_write+0x5ae/0x1150 fs/read_write.c:679 ksys_write+0x12b/0x250 fs/read_write.c:731 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fba9d7d5bf2 Code: 89 c7 48 89 44 24 08 e8 7b 34 fa ff 48 8b 44 24 08 48 83 c4 28 c3 c3 64 8b 04 25 18 00 00 00 85 c0 75 20 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 6f 48 8b 15 07 a2 0d 00 f7 d8 64 89 02 48 83 RSP: 002b:00007fffe3368478 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fba9d7d5bf2 RDX: 00000000000000af RSI: 000055e9946e6600 RDI: 0000000000000003 RBP: 000055e9946e6600 R08: 0000000000000001 R09: 0000000000000000 R10: 00007fba9d9743a3 R11: 0000000000000246 R12: 00000000000000af R13: 00007fba9d681480 R14: 0000000000000004 R15: 000055e9946e6410 rcu: rcu_preempt kthread starved for 10500 jiffies! g154821 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:27488 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0xe58/0x5ad0 kernel/sched/core.c:6756 __schedule_loop kernel/sched/core.c:6833 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6848 schedule_timeout+0x124/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2045 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2247 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 23798 Comm: kworker/u8:19 Not tainted 6.13.0-rc7-syzkaller-00102-gce69b4019001 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:__sanitizer_cov_trace_pc+0x18/0x70 kernel/kcov.c:213 Code: 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 65 48 8b 15 54 b4 69 7e 65 8b 05 55 b4 69 7e a9 00 01 ff 00 <48> 8b 34 24 74 1d f6 c4 01 74 43 a9 00 00 0f 00 75 3c a9 00 00 f0 RSP: 0018:ffffc9000e31f990 EFLAGS: 00000246 RAX: 0000000000000001 RBX: ffff8880b86469c0 RCX: ffffffff818e191c RDX: ffff8880461a2440 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000006 R12: ffffed10170c8d39 R13: 0000000000000001 R14: ffff8880b86469c8 R15: ffff8880b873fe40 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe4ddd77bac CR3: 000000000df7e000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rep_nop arch/x86/include/asm/vdso/processor.h:13 [inline] cpu_relax arch/x86/include/asm/vdso/processor.h:18 [inline] csd_lock_wait kernel/smp.c:340 [inline] smp_call_function_many_cond+0x456/0x1300 kernel/smp.c:884 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1051 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2114 [inline] text_poke_bp_batch+0x22b/0x760 arch/x86/kernel/alternative.c:2324 text_poke_flush arch/x86/kernel/alternative.c:2515 [inline] text_poke_flush arch/x86/kernel/alternative.c:2512 [inline] text_poke_finish+0x30/0x40 arch/x86/kernel/alternative.c:2522 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x1d7/0x400 kernel/jump_label.c:920 static_key_enable_cpuslocked+0x1b7/0x270 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate mm/kfence/core.c:849 [inline] toggle_allocation_gate+0xfc/0x260 mm/kfence/core.c:841 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3317 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244