rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=d30c/1/0x4000000000000000 softirq=64008/64017 fqs=0 rcu: (detected by 1, t=10505 jiffies, g=65381, q=1058 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 11722 Comm: syz.1.1452 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:__kasan_check_write+0x0/0x20 mm/kasan/shadow.c:36 Code: 0c 24 89 f6 31 d2 e9 0f f3 ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 f6 ba 01 00 00 00 e9 dc f2 ff ff 66 66 RSP: 0018:ffffc90000007da8 EFLAGS: 00000046 RAX: 0000000080010000 RBX: ffff88807b717000 RCX: ffffffff89c69122 RDX: ffff88802976a540 RSI: 0000000000000008 RDI: ffff88807b717198 RBP: ffff888054565800 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: 18bec0d19dd67e5b R14: ffff88806aaef000 R15: ffff88806aaef000 FS: 00007f2cea1a56c0(0000) GS:ffff888123dee000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2cea1a4ff8 CR3: 0000000055644000 CR4: 00000000003526f0 Call Trace: instrument_atomic_read_write include/linux/instrumented.h:112 [inline] test_and_set_bit include/asm-generic/bitops/instrumented-atomic.h:71 [inline] __netif_schedule.part.0+0x1f/0x2f0 net/core/dev.c:3404 __netif_schedule+0x4f/0x70 net/core/dev.c:3406 advance_sched+0x740/0xd20 net/sched/sch_taprio.c:993 __run_hrtimer kernel/time/hrtimer.c:2032 [inline] __hrtimer_run_queues+0x462/0x9c0 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2215 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x109/0x470 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:__do_adjtimex+0x8d0/0xe70 kernel/time/timekeeping.c:2985 Code: ff df 48 01 c1 48 c7 01 00 00 00 00 48 c7 41 08 00 00 00 00 48 8b 45 c8 65 48 2b 05 a2 7e 6c 12 0f 85 87 04 00 00 48 8d 65 d0 <44> 89 e8 5b 41 5a 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc e8 97 RSP: 0018:ffffc9001d85fc10 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000004000 RCX: fffff52003b0bf6e RDX: 0000000000080000 RSI: ffffffff81f6a137 RDI: 0000000000000001 RBP: ffffc9001d85fc40 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: ffffffffffffffff R12: ffffffff9b72d140 R13: 0000000000000005 R14: ffffc9001d85fc80 R15: 7fffffffffffffff do_adjtimex+0xa0/0x370 kernel/time/timekeeping.c:2996 do_clock_adjtime kernel/time/posix-timers.c:1169 [inline] __do_sys_clock_adjtime+0x177/0x290 kernel/time/posix-timers.c:1181 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: 0033:0x7f2ce939de59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f2cea1a5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000131 RAX: ffffffffffffffda RBX: 00007f2ce9626090 RCX: 00007f2ce939de59 RDX: 0000000000000000 RSI: 0000200000000280 RDI: 0000000000000000 RBP: 00007f2ce9433e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f2ce9626128 R14: 00007f2ce9626090 R15: 00007ffc5860d7c8 rcu: rcu_preempt kthread starved for 10505 jiffies! g65381 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:27528 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7326 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325 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: 11712 Comm: syz.4.1449 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x589/0x16c0 kernel/smp.c:892 Code: b8 00 00 00 00 00 fc ff df 48 8b 54 24 08 49 89 d5 49 89 d4 49 c1 ed 03 41 83 e4 07 49 01 c5 41 83 c4 03 e8 b9 95 0c 00 f3 90 <41> 0f b6 45 00 41 38 c4 7c 08 84 c0 0f 85 2c 0f 00 00 8b 45 08 31 RSP: 0018:ffffc9001d6f7650 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81fd3a8d RDX: ffff88802b8a4a80 RSI: ffffffff81fd3a67 RDI: ffff88802b8a4a80 RBP: ffff8880b8443680 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed10170886d1 R14: 0000000000000001 R15: ffff8880b853c880 FS: 0000000000000000(0000) GS:ffff888123eee000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2e116ff8 CR3: 0000000055644000 CR4: 00000000003526f0 Call Trace: 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 tlb_flush arch/x86/include/asm/tlb.h:23 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:509 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:499 [inline] tlb_flush_mmu mm/mmu_gather.c:423 [inline] tlb_finish_mmu+0x3fe/0x810 mm/mmu_gather.c:549 exit_mmap+0x454/0xa00 mm/mmap.c:1313 __mmput+0x12a/0x410 kernel/fork.c:1182 mmput+0x67/0x80 kernel/fork.c:1205 exit_mm kernel/exit.c:610 [inline] do_exit+0x8b1/0x2ae0 kernel/exit.c:992 do_group_exit+0xd5/0x2a0 kernel/exit.c:1147 get_signal+0x1ec7/0x21e0 kernel/signal.c:3038 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x139/0x6f0 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x666/0x870 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8af1b9de59 Code: Unable to access opcode bytes at 0x7f8af1b9de2f. RSP: 002b:00007f8af2b0ff38 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa RAX: 0000000000000001 RBX: 0000200000001540 RCX: 00007f8af1b9de59 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000004 RBP: 000000000000034e R08: 0000000000000000 R09: 0000000000000008 R10: 0000000000000000 R11: 0000000000000246 R12: 00002000000002c0 R13: 00002000000002c8 R14: 0000000000000e50 R15: 0000000000000000