rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=3244/1/0x4000000000000000 softirq=23063/23066 fqs=3 rcu: (detected by 1, t=10502 jiffies, g=15257, q=421 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 7124 Comm: syz.3.329 Not tainted 6.15.0-rc2-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x18/0x70 kernel/kcov.c:217 Code: 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 08 70 65 93 65 8b 15 a8 2b a2 11 <81> e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 3c 16 00 00 RSP: 0018:ffffc90000007d00 EFLAGS: 00000097 RAX: ffffffff81b0b6fb RBX: 0000000000000000 RCX: ffff888027ca1e00 RDX: 0000000000010002 RSI: 0000000000000000 RDI: 0000000000000007 RBP: 0000000000000000 R08: ffffffff81b0b6ed R09: 1ffffffff35317a2 R10: dffffc0000000000 R11: fffffbfff35317a3 R12: dffffc0000000000 R13: ffff8880b86278c0 R14: ffff888022aa5340 R15: ffff8880b86276c0 FS: 00007f774ab3c6c0(0000) GS:ffff888124fc9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000200 CR3: 0000000030f20000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: cpu_max_bits_warn include/linux/cpumask.h:135 [inline] cpumask_check include/linux/cpumask.h:142 [inline] cpumask_test_cpu include/linux/cpumask.h:587 [inline] cpu_online include/linux/cpumask.h:1143 [inline] trace_hrtimer_start include/trace/events/timer.h:222 [inline] debug_activate kernel/time/hrtimer.c:485 [inline] enqueue_hrtimer+0x5b/0x3c0 kernel/time/hrtimer.c:1088 __run_hrtimer kernel/time/hrtimer.c:1778 [inline] __hrtimer_run_queues+0x6d6/0xd40 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x110/0x420 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0xd9/0x140 kernel/locking/spinlock.c:194 Code: 9c 8f 44 24 20 42 80 3c 2b 00 74 08 4c 89 f7 e8 0d 5b ff f5 f6 44 24 21 02 75 55 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 82 e7 64 f5 65 8b 05 1b de 39 07 85 c0 74 46 48 c7 04 24 0e 36 RSP: 0018:ffffc9001bb1f920 EFLAGS: 00000206 RAX: 4b0ecf1316a55e00 RBX: 1ffff92003763f28 RCX: 0000000000000007 RDX: 0000000000000007 RSI: ffffffff8e687fbd RDI: 0000000000000001 RBP: ffffc9001bb1f9b0 R08: ffffffff905eb777 R09: 1ffffffff20bd6ee R10: dffffc0000000000 R11: fffffbfff20bd6ef R12: 1ffff92003763f24 R13: dffffc0000000000 R14: ffffc9001bb1f940 R15: 0000000000000246 clock_was_set+0x690/0x820 kernel/time/hrtimer.c:972 timekeeping_inject_offset+0x3e1/0x530 kernel/time/timekeeping.c:1420 do_adjtimex+0x62f/0xbd0 kernel/time/timekeeping.c:2520 do_clock_adjtime kernel/time/posix-timers.c:1170 [inline] __do_sys_clock_adjtime kernel/time/posix-timers.c:1182 [inline] __se_sys_clock_adjtime kernel/time/posix-timers.c:1173 [inline] __x64_sys_clock_adjtime+0x1e3/0x2a0 kernel/time/posix-timers.c:1173 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7749d8d169 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f774ab3c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000131 RAX: ffffffffffffffda RBX: 00007f7749fa5fa0 RCX: 00007f7749d8d169 RDX: 0000000000000000 RSI: 0000200000000480 RDI: 0000000000000000 RBP: 00007f7749e0e990 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f7749fa5fa0 R15: 00007ffccad5ac48 rcu: rcu_preempt kthread starved for 10496 jiffies! g15257 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:25512 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b33/0x51f0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x163/0x360 kernel/sched/core.c:6860 schedule_timeout+0x15b/0x2b0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2e1/0x1340 kernel/rcu/tree.c:2046 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2248 kthread+0x7b7/0x940 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 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: 5837 Comm: syz-executor Not tainted 6.15.0-rc2-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0x1bac/0x2d40 kernel/smp.c:885 Code: 03 84 c0 75 7e 45 8b 65 00 44 89 e6 83 e6 01 31 ff e8 08 e3 0b 00 41 83 e4 01 4c 8b 64 24 68 75 07 e8 b8 de 0b 00 eb 41 f3 90 <48> b8 00 00 00 00 00 fc ff df 0f b6 04 03 84 c0 75 11 41 f7 45 00 RSP: 0018:ffffc9000408f4c0 EFLAGS: 00000293 RAX: ffffffff81b765dd RBX: 1ffff110170c8219 RCX: ffff88805ff09e00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000408f6c0 R08: ffffffff81b765a8 R09: 1ffffffff20bd6ee R10: dffffc0000000000 R11: fffffbfff20bd6ef R12: ffff8880b873ab88 R13: ffff8880b86410c8 R14: ffff8880b873ab80 R15: 0000000000000000 FS: 000055558bcbf500(0000) GS:ffff8881250c9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2d09a5a290 CR3: 000000005fec2000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1275 [inline] flush_tlb_mm_range+0xb8d/0x13f0 arch/x86/mm/tlb.c:1365 dup_mmap kernel/fork.c:765 [inline] dup_mm kernel/fork.c:1734 [inline] copy_mm+0x19de/0x22c0 kernel/fork.c:1786 copy_process+0x17de/0x3d10 kernel/fork.c:2429 kernel_clone+0x227/0x880 kernel/fork.c:2844 __do_sys_clone kernel/fork.c:2987 [inline] __se_sys_clone kernel/fork.c:2971 [inline] __x64_sys_clone+0x268/0x2e0 kernel/fork.c:2971 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6a245839d3 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:00007ffd7b6798f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f6a245839d3 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 000055558bcbf7d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 000000000002bbe6 R15: 00007ffd7b679a90