rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 ticks this GP) idle=ddc4/1/0x4000000000000000 softirq=43618/43618 fqs=1 rcu: (detected by 0, t=10502 jiffies, g=40061, q=93 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 11255 Comm: syz.1.1416 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x10/0x70 kernel/kcov.c:217 Code: 00 00 5b e9 12 dd ed 02 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 34 24 65 48 8b 15 98 c9 f3 11 <65> 8b 05 a9 c9 f3 11 a9 00 01 ff 00 74 1d f6 c4 01 74 43 a9 00 00 RSP: 0018:ffffc90000a08d88 EFLAGS: 00000046 RAX: 0000000000010002 RBX: ffff888077e13300 RCX: ffffffff8980b13c RDX: ffff88802828c980 RSI: ffffffff8980b247 RDI: 0000000000000004 RBP: ffff888056b14400 R08: 0000000000000004 R09: 0000000000000002 R10: 0000000000000002 R11: ffff88802828d4b0 R12: 0000000000000001 R13: 188e480332c6b220 R14: 0000000000000002 R15: ffff888056b14c10 FS: 00007f90a3d646c0(0000) GS:ffff8881249f5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2f863fff CR3: 000000003880f000 CR4: 00000000003526f0 Call Trace: should_change_schedules net/sched/sch_taprio.c:890 [inline] advance_sched+0x4e7/0xc80 net/sched/sch_taprio.c:974 __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x202/0xc40 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline] __sysvec_apic_timer_interrupt+0x10b/0x3c0 arch/x86/kernel/apic/apic.c:1062 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:console_flush_one_record+0x995/0xc60 kernel/printk/printk.c:3216 Code: 00 e8 2f 2b 2a 00 9c 5d 81 e5 00 02 00 00 31 ff 48 89 ee e8 7d 03 22 00 48 85 ed 0f 85 8e 01 00 00 e8 9f 08 22 00 fb 4c 89 e8 <48> c1 e8 03 42 80 3c 38 00 0f 84 b4 fe ff ff 4c 89 ef e8 84 e2 8b RSP: 0018:ffffc9000b8cf228 EFLAGS: 00000293 RAX: ffffffff8f093338 RBX: 0000000000000001 RCX: ffffffff819cddc3 RDX: ffff88802828c980 RSI: ffffffff819cddd1 RDI: 0000000000000007 RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: ffff88802828d4b0 R12: 0000000000000001 R13: ffffffff8f093338 R14: ffffffff8f0932e0 R15: dffffc0000000000 console_flush_all kernel/printk/printk.c:3289 [inline] __console_flush_and_unlock kernel/printk/printk.c:3319 [inline] console_unlock+0xef/0x240 kernel/printk/printk.c:3359 vprintk_emit+0x407/0x6b0 kernel/printk/printk.c:2426 _printk+0xc7/0x100 kernel/printk/printk.c:2451 audit_log_start+0x856/0x950 kernel/audit.c:1946 common_lsm_audit+0xb2/0x300 security/lsm_audit.c:442 slow_avc_audit+0x186/0x210 security/selinux/avc.c:779 audit_inode_permission+0x1ea/0x2b0 security/selinux/hooks.c:3119 selinux_inode_permission+0xe0c/0x1190 security/selinux/hooks.c:3266 security_inode_permission+0xda/0x260 security/security.c:1816 inode_permission+0x373/0x640 fs/namei.c:604 may_open+0x111/0x470 fs/namei.c:4204 do_open fs/namei.c:4626 [inline] path_openat+0xdc0/0x3140 fs/namei.c:4787 do_filp_open+0x20b/0x470 fs/namei.c:4814 do_sys_openat2+0x121/0x290 fs/open.c:1430 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __x64_sys_openat+0x174/0x210 fs/open.c:1447 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f90a2f8df90 Code: 48 89 44 24 20 75 93 44 89 54 24 0c e8 69 95 02 00 44 8b 54 24 0c 89 da 48 89 ee 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 77 38 44 89 c7 89 44 24 0c e8 bc 95 02 00 8b 44 RSP: 002b:00007f90a3d63f10 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f90a2f8df90 RDX: 0000000000000002 RSI: 00007f90a3d63fa0 RDI: 00000000ffffff9c RBP: 00007f90a3d63fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007f90a31e6128 R14: 00007f90a31e6090 R15: 00007fffec9e3088 rcu: rcu_preempt kthread starved for 10500 jiffies! g40061 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:28056 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6960 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: c6 5f 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 13 49 12 00 fb f4 cc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffffff8e007df8 EFLAGS: 000002c6 RAX: 000000000187201f RBX: 0000000000000000 RCX: ffffffff8b7816d9 RDX: 0000000000000000 RSI: ffffffff8dacdf23 RDI: ffffffff8bf2b400 RBP: fffffbfff1c12f68 R08: 0000000000000001 R09: ffffed101708673d R10: ffff8880b84339eb R11: ffffffff8e098670 R12: 0000000000000000 R13: ffffffff8e097b40 R14: ffffffff9088b4d0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881248f5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f05777733e0 CR3: 00000000754bc000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x38d/0x510 kernel/sched/idle.c:332 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430 rest_init+0x16b/0x2b0 init/main.c:757 start_kernel+0x3ef/0x4d0 init/main.c:1206 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x148