rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=5f5c/1/0x4000000000000000 softirq=47482/47483 fqs=17 rcu: (detected by 1, t=10502 jiffies, g=41733, q=565 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 8477 Comm: syz-executor 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:__sanitizer_cov_trace_const_cmp4+0x0/0x90 kernel/kcov.c:313 Code: 7c 11 10 48 89 74 11 18 48 89 44 11 20 e9 d3 44 4f ff cc 0f 1f 80 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 04 24 65 48 8b 14 25 08 10 80 92 65 8b 0d c8 13 RSP: 0018:ffffc90000007c68 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffff888029218000 RDX: 0000000000010000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000002 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000000f7c R12: ffff888032129300 R13: ffff888032129000 R14: dffffc0000000000 R15: ffff8880560fc400 FS: 0000555579cd6500(0000) GS:ffff888125e1f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fdf95b156c0 CR3: 00000000850ba000 CR4: 0000000000350ef0 Call Trace: advance_sched+0x14d/0xc90 net/sched/sch_taprio.c:933 __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x51c/0xc30 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline] __sysvec_apic_timer_interrupt+0x102/0x3e0 arch/x86/kernel/apic/apic.c:1062 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:kasan_quarantine_reduce+0x9/0x160 mm/kasan/quarantine.c:244 Code: 6a 17 73 aa eb c2 66 66 2e 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 1f 40 d6 53 48 83 ec 20 <48> c7 44 24 18 00 00 00 00 48 c7 44 24 10 00 00 00 00 48 c7 44 24 RSP: 0018:ffffc9000406f870 EFLAGS: 00000282 RAX: ffff8880591c3f01 RBX: ffff888140e92900 RCX: 0000000000400cc0 RDX: 0000000000000048 RSI: ffff888140e92900 RDI: ffff88813ffae640 RBP: 0000000000400cc0 R08: ffffffff82303bc9 R09: ffffffff8df41aa0 R10: 000000000000000b R11: ffffffff81acf420 R12: 0000000000000048 R13: ffff88813ffae640 R14: ffff88813ffae640 R15: 0000000000000048 __kasan_kmalloc+0x22/0xb0 mm/kasan/common.c:406 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5657 [inline] __kvmalloc_node_noprof+0x5d5/0x920 mm/slub.c:7136 alloc_fdtable+0x169/0x2c0 fs/file.c:224 dup_fd+0x84f/0xb40 fs/file.c:420 copy_files+0xc9/0x120 kernel/fork.c:1635 copy_process+0x1513/0x3950 kernel/fork.c:2209 kernel_clone+0x21e/0x820 kernel/fork.c:2651 __do_sys_clone kernel/fork.c:2792 [inline] __se_sys_clone kernel/fork.c:2776 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2776 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdf94d85e93 Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 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 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffe734bbb28 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fdf94d85e93 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 0000555579cd67d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 00000000000825d7 R15: 00007ffe734bbcc0 rcu: rcu_preempt kthread starved for 10466 jiffies! g41733 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:27032 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 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: 1 UID: 0 PID: 9529 Comm: syz.6.783 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:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xcc5/0x1260 kernel/smp.c:877 Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 e4 97 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 8f 93 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 73 93 RSP: 0018:ffffc9000ed0f600 EFLAGS: 00000246 RAX: ffffffff81b5649d RBX: 1ffff110170c856d RCX: 0000000000080000 RDX: ffffc9000cbb9000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc9000ed0f740 R08: ffffffff8f822577 R09: 1ffffffff1f044ae R10: dffffc0000000000 R11: fffffbfff1f044af R12: ffff8880b8642b68 R13: dffffc0000000000 R14: ffff8880b873bb00 R15: 0000000000000000 FS: 00007fcfe56b76c0(0000) GS:ffff888125f1f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2a10380d58 CR3: 0000000031104000 CR4: 0000000000350ef0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline] flush_tlb_mm_range+0x60a/0x1170 arch/x86/mm/tlb.c:1472 tlb_flush arch/x86/include/asm/tlb.h:23 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:490 [inline] tlb_flush_mmu+0x1a7/0x680 mm/mmu_gather.c:403 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497 vms_clear_ptes+0x42b/0x530 mm/vma.c:1238 vms_complete_munmap_vmas+0x206/0x8a0 mm/vma.c:1280 do_vmi_align_munmap+0x364/0x440 mm/vma.c:1539 do_vmi_munmap+0x253/0x2e0 mm/vma.c:1587 __vm_munmap+0x207/0x380 mm/vma.c:3203 __do_sys_munmap mm/mmap.c:1077 [inline] __se_sys_munmap mm/mmap.c:1074 [inline] __x64_sys_munmap+0x60/0x70 mm/mmap.c:1074 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fcfe478f7d7 Code: 00 00 00 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fcfe56b6e18 EFLAGS: 00000246 ORIG_RAX: 000000000000000b RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007fcfe478f7d7 RDX: 0000000000000000 RSI: 0000000008400000 RDI: 00007fcfda400000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000037f93 R10: 00002000000a7ec2 R11: 0000000000000246 R12: 0000000000000005 R13: 00007fcfe56b6ef0 R14: 00007fcfe56b6eb0 R15: 00007fcfda400000