rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (2 ticks this GP) idle=d834/1/0x4000000000000000 softirq=77898/77898 fqs=0 rcu: (detected by 0, t=10505 jiffies, g=70033, q=1676 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 15704 Comm: udevd Not tainted 6.16.0-rc2-syzkaller-00024-g9afe652958c3 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x0/0x20 kernel/kcov.c:313 Code: 0c 24 0f b7 d6 0f b7 f7 bf 03 00 00 00 e9 58 fe ff ff 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 0c 24 89 f2 89 fe bf 05 00 00 00 e9 2a fe ff ff RSP: 0018:ffffc90000a08d80 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000001 RCX: 00000000ef9d33e4 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffff888033ab8800 R08: 0ac0d5affe09d4ff R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: 000000cbc2078080 R13: 000000cbc2078080 R14: 0000000000000002 R15: ffff888033abb410 FS: 00007f06835e1880(0000) GS:ffff888124853000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055555c6c75c8 CR3: 000000001b9f9000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock include/linux/rcupdate.h:842 [inline] advance_sched+0x6a9/0xc80 net/sched/sch_taprio.c:985 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x202/0xad0 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x108/0x3f0 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:rcu_preempt_read_enter kernel/rcu/tree_plugin.h:391 [inline] RIP: 0010:__rcu_read_lock+0x26/0xf0 kernel/rcu/tree_plugin.h:414 Code: 90 90 90 90 f3 0f 1e fa 48 b8 00 00 00 00 00 fc ff df 55 53 65 48 8b 1d 20 89 2b 12 48 8d bb 44 04 00 00 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 a6 RSP: 0018:ffffc90003f0f960 EFLAGS: 00000a07 RAX: dffffc0000000000 RBX: ffff88807eda8000 RCX: ffffc90003f0f93c RDX: 1ffff1100fdb5088 RSI: ffffffff821829cd RDI: ffff88807eda8444 RBP: ffffc90003f0fa30 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 000000000000a297 R12: ffffffff81a77fd0 R13: ffffc90003f0f9e8 R14: 0000000000000000 R15: ffff88807eda8000 rcu_read_lock include/linux/rcupdate.h:839 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xae/0x20a0 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:548 __call_rcu_common.constprop.0+0x9a/0x9f0 kernel/rcu/tree.c:3090 slab_free_hook mm/slub.c:2345 [inline] slab_free mm/slub.c:4643 [inline] kmem_cache_free+0x16d/0x4d0 mm/slub.c:4745 file_free fs/file_table.c:76 [inline] __fput+0x68d/0xb70 fs/file_table.c:478 fput_close_sync+0x118/0x260 fs/file_table.c:570 __do_sys_close fs/open.c:1589 [inline] __se_sys_close fs/open.c:1574 [inline] __x64_sys_close+0x8b/0x120 fs/open.c:1574 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0682ea7407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffdf332ff40 EFLAGS: 00000202 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 00007f06835e1880 RCX: 00007f0682ea7407 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000009 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffdf332ffa0 R13: 0000000000000001 R14: 0000564cc9e866d7 R15: 00007ffdf3332240 rcu: rcu_preempt kthread timer wakeup didn't happen for 10504 jiffies! g70033 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=52069 rcu: rcu_preempt kthread starved for 10505 jiffies! g70033 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:28264 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6878 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2256 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245