rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=b904/1/0x4000000000000000 softirq=115087/115096 fqs=2 rcu: (detected by 1, t=10502 jiffies, g=126981, q=524 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 4986 Comm: udevd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:lock_acquire+0x0/0x370 kernel/locking/lockdep.c:5828 Code: d6 f3 f5 0e 48 c7 c6 ec b9 ef 8d 67 48 0f b9 3a e9 28 fc ff ff 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 41 57 41 56 41 89 f6 41 55 45 89 c5 41 54 41 89 cc 55 RSP: 0018:ffffc90000007dc8 EFLAGS: 00000046 RAX: ffffffff899a9207 RBX: ffff88802a9d5300 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e7e5560 RBP: ffff88807a3ae400 R08: 0000000000000000 R09: 0000000000000000 R10: ffff88802a9d52ab R11: 0000000000000001 R12: 0000000000000000 R13: 0000031408ce054c R14: ffff88807a3aec00 R15: ffff88807a3aec00 FS: 00007f5b4b456880(0000) GS:ffff888124383000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b31017ff8 CR3: 000000002a58f000 CR4: 00000000003526f0 Call Trace: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] advance_sched+0x718/0xd20 net/sched/sch_taprio.c:992 __run_hrtimer kernel/time/hrtimer.c:1930 [inline] __hrtimer_run_queues+0x470/0xa00 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x10b/0x460 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:198 Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 c6 2d 58 f6 48 89 df e8 9e 7d 58 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 b5 49 48 f6 65 8b 05 9e 6d 7d 08 85 c0 74 16 5b RSP: 0018:ffffc90002f975d8 EFLAGS: 00000246 RAX: 0000000000000006 RBX: ffffffff9b319168 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8df0f8f1 RDI: ffffffff8c1c4680 RBP: 0000000000000282 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000200 R14: 0000000000000282 R15: 0000000000000025 spin_unlock_irqrestore include/linux/spinlock.h:408 [inline] avc_reclaim_node security/selinux/avc.c:488 [inline] avc_alloc_node+0x3f5/0x670 security/selinux/avc.c:507 avc_insert security/selinux/avc.c:618 [inline] avc_compute_av+0x101/0x820 security/selinux/avc.c:993 avc_perm_nonode+0xb1/0x180 security/selinux/avc.c:1117 avc_has_perm_noaudit+0x2d4/0x3b0 security/selinux/avc.c:1160 avc_has_perm+0xbd/0x1e0 security/selinux/avc.c:1195 inode_has_perm+0x166/0x1d0 security/selinux/hooks.c:1692 file_path_has_perm security/selinux/hooks.c:1742 [inline] selinux_file_open+0x39d/0x510 security/selinux/hooks.c:4276 security_file_open+0xd7/0x1e0 security/security.c:2739 do_dentry_open+0x588/0x14d0 fs/open.c:924 vfs_open+0x82/0x3f0 fs/open.c:1079 do_open fs/namei.c:4699 [inline] path_openat+0x208c/0x31a0 fs/namei.c:4858 do_file_open+0x20e/0x430 fs/namei.c:4887 do_sys_openat2+0x10d/0x1e0 fs/open.c:1364 do_sys_open fs/open.c:1370 [inline] __do_sys_openat fs/open.c:1386 [inline] __se_sys_openat fs/open.c:1381 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1381 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5b4aca7407 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:00007ffe8fc504e0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f5b4b456880 RCX: 00007f5b4aca7407 RDX: 0000000000080000 RSI: 00007ffe8fc50660 RDI: ffffffffffffff9c RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000564948f947f5 R13: 0000564948f947f5 R14: 0000000000000001 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10498 jiffies! g126981 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:28904 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1295/0x67a0 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7283 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 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: 15496 Comm: syz-executor Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:check_kcov_mode kernel/kcov.c:185 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x39/0x70 kernel/kcov.c:217 Code: 65 48 8b 15 41 20 01 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 c3 cc cc cc cc 8b 82 ec 16 00 00 85 c0 74 f1 <8b> 82 c8 16 00 00 83 f8 02 75 e6 48 8b 8a d0 16 00 00 8b 92 cc 16 RSP: 0018:ffffc900031c7610 EFLAGS: 00000246 RAX: 0000000000000002 RBX: 0000000000000000 RCX: ffffffff81fc2c4d RDX: ffff8880307b2540 RSI: ffffffff81fc2c27 RDI: ffff8880307b2540 RBP: ffff8880b8443360 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed101708866d R14: 0000000000000001 R15: ffff8880b853c600 FS: 00005555644cb500(0000) GS:ffff888124483000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc3a8d456b8 CR3: 000000002e80e000 CR4: 00000000003526f0 Call Trace: native_pause 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:342 [inline] smp_call_function_many_cond+0x587/0x1700 kernel/smp.c:892 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1057 __flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x45f/0x16f0 arch/x86/mm/tlb.c:1451 dup_mmap+0x1307/0x21b0 mm/mmap.c:1905 dup_mm kernel/fork.c:1534 [inline] copy_mm kernel/fork.c:1586 [inline] copy_process+0x6c78/0x7ed0 kernel/fork.c:2264 kernel_clone+0x176/0x9e0 kernel/fork.c:2722 __do_sys_clone+0xd9/0x120 kernel/fork.c:2863 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc3a7fc58d2 Code: 89 e7 e8 71 8b f7 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffd0e1d18a0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffd0e1d18a0 RCX: 00007fc3a7fc58d2 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffd0e1d1a2c R08: 0000000000000000 R09: 0000000000000001 R10: 00005555644cb7d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 000000000010a182 R15: 00007ffd0e1d1a80