rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 ticks this GP) idle=d26c/1/0x4000000000000000 softirq=29288/29288 fqs=9 rcu: (detected by 1, t=10502 jiffies, g=21757, q=675 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 7837 Comm: modprobe Not tainted 6.15.0-rc2-syzkaller-00563-g240ce924d271 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:timerqueue_del+0x51/0x100 lib/timerqueue.c:55 Code: c1 ec 03 41 80 3c 2c 00 74 08 4c 89 ef e8 e7 b5 04 f6 49 8b 5d 00 48 89 df 4c 89 ee e8 b8 78 9a f5 4c 39 eb 0f 84 99 00 00 00 4a 76 9a f5 49 8d 5e 08 49 89 df 49 c1 ef 03 41 80 3c 2f 00 74 RSP: 0018:ffffc90000007d08 EFLAGS: 00000003 RAX: 0000000000010000 RBX: 0000000000000001 RCX: ffff88802d58da00 RDX: 0000000000010000 RSI: ffff888143ee0340 RDI: 0000000000000001 RBP: dffffc0000000000 R08: ffffffff8c284468 R09: 1ffffffff20bfb8e R10: dffffc0000000000 R11: fffffbfff20bfb8f R12: 1ffff110287dc068 R13: ffff888143ee0340 R14: ffff8880b8627890 R15: ffff8880b86276c0 FS: 0000000000000000(0000) GS:ffff888124fab000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f15ad9183b0 CR3: 00000000580b6000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __remove_hrtimer kernel/time/hrtimer.c:1121 [inline] __run_hrtimer kernel/time/hrtimer.c:1741 [inline] __hrtimer_run_queues+0x3db/0xd40 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x110/0x420 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x167/0x2f0 arch/x86/include/asm/irqflags.h:-1 Code: c7 44 24 10 00 00 00 00 9c 8f 44 24 10 f7 44 24 10 00 02 00 00 0f 85 fd 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 65 48 8b 45 00 <48> 3b 44 24 38 0f 85 72 01 00 00 48 83 c4 40 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc90003966f88 EFLAGS: 00000206 RAX: 258a52f5f296e600 RBX: ffffffff8ed3df20 RCX: 258a52f5f296e600 RDX: 0000000000000000 RSI: ffffffff8e4d854b RDI: ffffffff8ca1c5c0 RBP: ffffffff93675020 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000002 R14: 0000000000000246 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xd5/0x23b0 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11e/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x11a/0x1d0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x9d/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4341 [inline] __kmalloc_noprof+0x28e/0x4d0 mm/slub.c:4353 kmalloc_noprof include/linux/slab.h:909 [inline] tomoyo_realpath_from_path+0xcf/0x5e0 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_check_open_permission+0x25a/0x4f0 security/tomoyo/file.c:771 security_file_open+0xac/0x250 security/security.c:3114 do_dentry_open+0x320/0x1960 fs/open.c:933 vfs_open+0x3b/0x370 fs/open.c:1086 do_open fs/namei.c:3845 [inline] path_openat+0x2caf/0x35d0 fs/namei.c:4004 do_filp_open+0x284/0x4e0 fs/namei.c:4031 do_sys_openat2+0x12b/0x1d0 fs/open.c:1429 do_sys_open fs/open.c:1444 [inline] __do_sys_openat fs/open.c:1460 [inline] __se_sys_openat fs/open.c:1455 [inline] __x64_sys_openat+0x249/0x2a0 fs/open.c:1455 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f15adb93a46 Code: 10 00 00 00 44 8b 54 24 e0 48 89 44 24 c0 48 8d 44 24 d0 48 89 44 24 c8 44 89 c2 4c 89 ce bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 76 0c f7 d8 89 05 0a 48 01 00 48 83 c8 ff c3 31 RSP: 002b:00007ffcca2af908 EFLAGS: 00000287 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007ffcca2afb68 RCX: 00007f15adb93a46 RDX: 0000000000080000 RSI: 00007ffcca2af980 RDI: 00000000ffffff9c RBP: 00007ffcca2af970 R08: 0000000000080000 R09: 00007ffcca2af980 R10: 0000000000000000 R11: 0000000000000287 R12: 00007ffcca2af980 R13: 0000000000000009 R14: 00007ffcca2afb4f R15: 00000000ffffffff rcu: rcu_preempt kthread starved for 9671 jiffies! g21757 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:26952 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x163/0x360 kernel/sched/core.c:6860 schedule_timeout+0x15b/0x2b0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2e1/0x1340 kernel/rcu/tree.c:2046 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2248 kthread+0x7b7/0x940 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted 6.15.0-rc2-syzkaller-00563-g240ce924d271 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0x1bac/0x2d40 kernel/smp.c:885 Code: 03 84 c0 75 7e 45 8b 65 00 44 89 e6 83 e6 01 31 ff e8 68 dc 0b 00 41 83 e4 01 4c 8b 64 24 68 75 07 e8 18 d8 0b 00 eb 41 f3 90 <48> b8 00 00 00 00 00 fc ff df 0f b6 04 03 84 c0 75 11 41 f7 45 00 RSP: 0018:ffffc90000117640 EFLAGS: 00000293 RAX: ffffffff81b6e2cd RBX: 1ffff110170c823d RCX: ffff88801d6dda00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90000117840 R08: ffffffff81b6e298 R09: 1ffffffff20bfb8e R10: dffffc0000000000 R11: fffffbfff20bfb8f R12: ffff8880b873ad08 R13: ffff8880b86411e8 R14: ffff8880b873ad00 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881250ab000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9e4be7a440 CR3: 000000000eb38000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2455 [inline] text_poke_bp_batch+0x728/0xb30 arch/x86/kernel/alternative.c:2727 text_poke_flush arch/x86/kernel/alternative.c:2856 [inline] text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2863 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x136/0x260 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate+0xc0/0x250 mm/kfence/core.c:850 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319 worker_thread+0x870/0xd50 kernel/workqueue.c:3400 kthread+0x7b7/0x940 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245