rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=e984/1/0x4000000000000000 softirq=16937/16937 fqs=2 rcu: (detected by 0, t=10502 jiffies, g=23457, q=418 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 6434 Comm: udevd Not tainted 6.9.0-rc4-syzkaller-00173-g3cdb45594619 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 RIP: 0010:__sanitizer_cov_trace_pc+0x18/0x60 kernel/kcov.c:203 Code: 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 65 48 8b 15 24 15 76 7e 65 8b 05 25 15 76 7e a9 00 01 ff 00 <48> 8b 34 24 74 0f f6 c4 01 74 35 8b 82 14 16 00 00 85 c0 74 2b 8b RSP: 0018:ffffc90000a08df0 EFLAGS: 00000006 RAX: 0000000080010002 RBX: ffff88802e38f340 RCX: ffffffff817af314 RDX: ffff88801cbd9e00 RSI: 0000000000000000 RDI: 0000000000000001 RBP: ffff8880b952cac0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000002 R12: 0000000000000001 R13: 0000000000000000 R14: ffff8880b952c9c0 R15: 0000000000000000 FS: 00007fbf88f36c80(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff2f650ed58 CR3: 000000007f6d4000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __remove_hrtimer+0x8d/0x290 kernel/time/hrtimer.c:1123 __run_hrtimer kernel/time/hrtimer.c:1672 [inline] __hrtimer_run_queues+0x577/0xcc0 kernel/time/hrtimer.c:1756 hrtimer_interrupt+0x31b/0x800 kernel/time/hrtimer.c:1818 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1032 [inline] __sysvec_apic_timer_interrupt+0x10f/0x450 arch/x86/kernel/apic/apic.c:1049 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__sanitizer_cov_trace_switch+0x54/0x90 kernel/kcov.c:340 Code: 41 bd 03 00 00 00 4c 8b 75 00 31 db 4d 85 f6 74 1e 48 8b 74 dd 10 4c 89 e2 4c 89 ef 48 83 c3 01 48 8b 4c 24 28 e8 8c fd ff ff <49> 39 de 75 e2 5b 5d 41 5c 41 5d 41 5e c3 cc cc cc cc 48 83 f8 40 RSP: 0018:ffffc9000315f720 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000002 RCX: ffffffff813d1d91 RDX: ffff88801cbd9e00 RSI: 0000000000000003 RDI: 0000000000000001 RBP: ffffffff8b09cea0 R08: 0000000000000001 R09: 0000000000000003 R10: 0000000000000005 R11: 0000000000000001 R12: 0000000000000005 R13: 0000000000000001 R14: 0000000000000008 R15: ffffc9000315f805 unwind_next_frame+0x6c1/0x23a0 arch/x86/kernel/unwind_orc.c:515 arch_stack_walk+0x100/0x170 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579 poison_slab_object mm/kasan/common.c:240 [inline] __kasan_slab_free+0x11d/0x1a0 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2106 [inline] slab_free mm/slub.c:4280 [inline] kfree+0x129/0x390 mm/slub.c:4390 tomoyo_realpath_from_path+0x1ad/0x720 security/tomoyo/realpath.c:286 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_number_perm+0x245/0x590 security/tomoyo/file.c:723 security_file_ioctl+0x75/0xc0 security/security.c:2764 __do_sys_ioctl fs/ioctl.c:898 [inline] __se_sys_ioctl fs/ioctl.c:890 [inline] __x64_sys_ioctl+0xbb/0x220 fs/ioctl.c:890 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbf88b1ad49 Code: 5c c3 48 8d 44 24 08 48 89 54 24 e0 48 89 44 24 c0 48 8d 44 24 d0 48 89 44 24 c8 b8 10 00 00 00 c7 44 24 b8 10 00 00 00 0f 05 <41> 89 c0 3d 00 f0 ff ff 76 10 48 8b 15 ae 60 0d 00 f7 d8 41 83 c8 RSP: 002b:00007fffc6604ce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007fbf88b1ad49 RDX: 00007fffc6604d20 RSI: 0000000080280215 RDI: 0000000000000009 RBP: 0000555c4f9b42a0 R08: 0000000000000000 R09: 00007fbf88bf1c10 R10: 0000000000001000 R11: 0000000000000246 R12: 0000000000000009 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001 rcu: rcu_preempt kthread starved for 10490 jiffies! g23457 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:R running task stack:28736 pid:16 tgid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5409 [inline] __schedule+0xf15/0x5d00 kernel/sched/core.c:6746 __schedule_loop kernel/sched/core.c:6823 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6838 schedule_timeout+0x136/0x2a0 kernel/time/timer.c:2582 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:1663 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:1862 kthread+0x2c1/0x3a0 kernel/kthread.c:388 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: 0 PID: 2437 Comm: kworker/u8:8 Not tainted 6.9.0-rc4-syzkaller-00173-g3cdb45594619 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:write_comp_data+0x34/0x90 kernel/kcov.c:236 Code: 48 8b 15 ff 1b 76 7e 65 8b 05 00 1c 76 7e a9 00 01 ff 00 74 0f f6 c4 01 74 59 8b 82 14 16 00 00 85 c0 74 4f 8b 82 f0 15 00 00 <83> f8 03 75 44 48 8b 82 f8 15 00 00 8b 92 f4 15 00 00 48 8b 38 48 RSP: 0018:ffffc90009e3f908 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff8880b9544700 RCX: ffffffff8181bb1b RDX: ffff8880296e3c00 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000006 R12: ffffed10172a88e1 R13: 0000000000000001 R14: ffff8880b9544708 R15: ffff8880b943fc00 FS: 0000000000000000(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000040 CR3: 000000000d57a000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: csd_lock_wait kernel/smp.c:311 [inline] smp_call_function_many_cond+0x50b/0x1420 kernel/smp.c:855 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1023 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2086 [inline] text_poke_bp_batch+0x22b/0x760 arch/x86/kernel/alternative.c:2296 text_poke_flush arch/x86/kernel/alternative.c:2487 [inline] text_poke_flush arch/x86/kernel/alternative.c:2484 [inline] text_poke_finish+0x30/0x40 arch/x86/kernel/alternative.c:2494 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x1d7/0x400 kernel/jump_label.c:829 static_key_enable_cpuslocked+0x1b7/0x270 kernel/jump_label.c:205 static_key_enable+0x1a/0x20 kernel/jump_label.c:218 toggle_allocation_gate mm/kfence/core.c:826 [inline] toggle_allocation_gate+0xf8/0x250 mm/kfence/core.c:818 process_one_work+0x9a9/0x1ac0 kernel/workqueue.c:3254 process_scheduled_works kernel/workqueue.c:3335 [inline] worker_thread+0x6c8/0xf70 kernel/workqueue.c:3416 kthread+0x2c1/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244