rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5832/1:b..l P5204/1:b..l rcu: (detected by 0, t=10502 jiffies, g=30589, q=142 ncpus=2) task:udevd state:R running task stack:21856 pid:5204 tgid:5204 ppid:1 task_flags:0x40054c flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0x190e/0x4c90 kernel/sched/core.c:6765 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6944 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6968 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] zap_pte_range mm/memory.c:1772 [inline] zap_pmd_range mm/memory.c:1834 [inline] zap_pud_range mm/memory.c:1863 [inline] zap_p4d_range mm/memory.c:1884 [inline] unmap_page_range+0x3a0d/0x4510 mm/memory.c:1905 unmap_vmas+0x3cc/0x5f0 mm/memory.c:1995 exit_mmap+0x283/0xd40 mm/mmap.c:1284 __mmput+0x115/0x420 kernel/fork.c:1356 exit_mm+0x220/0x310 kernel/exit.c:570 do_exit+0x9ad/0x28e0 kernel/exit.c:925 do_group_exit+0x207/0x2c0 kernel/exit.c:1087 get_signal+0x168c/0x1720 kernel/signal.c:3036 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1dddb1a477 RSP: 002b:00007ffe6ebb81a8 EFLAGS: 00000287 ORIG_RAX: 0000000000000101 RAX: 000000000000000d RBX: 000055bc295bddf0 RCX: 00007f1dddb1a477 RDX: 0000000000090800 RSI: 000055bc295bf310 RDI: 00000000ffffff9c RBP: 000055bc295d4150 R08: 0000000000090800 R09: 000055bc295bf310 R10: 0000000000000000 R11: 0000000000000287 R12: 000055bc295bf310 R13: 00000000000000ff R14: 000055bc161f01c4 R15: 0000000000000000 task:syz-executor state:R running task stack:14448 pid:5832 tgid:5832 ppid:5828 task_flags:0x400140 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0x190e/0x4c90 kernel/sched/core.c:6765 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6944 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6968 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_pte_range mm/memory.c:1201 [inline] copy_pmd_range+0x6ddc/0x77b0 mm/memory.c:1262 copy_pud_range mm/memory.c:1299 [inline] copy_p4d_range mm/memory.c:1323 [inline] copy_page_range+0x99f/0xe90 mm/memory.c:1421 dup_mmap kernel/fork.c:748 [inline] dup_mm kernel/fork.c:1700 [inline] copy_mm+0x1269/0x2160 kernel/fork.c:1752 copy_process+0x17d1/0x3cf0 kernel/fork.c:2403 kernel_clone+0x226/0x8e0 kernel/fork.c:2815 __do_sys_clone kernel/fork.c:2958 [inline] __se_sys_clone kernel/fork.c:2942 [inline] __x64_sys_clone+0x267/0x2e0 kernel/fork.c:2942 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0dab1839d3 RSP: 002b:00007fff154eacd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0dab1839d3 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 0000555567c537d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 000000000003ca96 R15: 00007fff154eae70 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g30589 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=16259 rcu: rcu_preempt kthread starved for 10502 jiffies! g30589 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26104 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0x190e/0x4c90 kernel/sched/core.c:6765 __schedule_loop kernel/sched/core.c:6842 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6857 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2024 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2226 kthread+0x7ab/0x920 kernel/kthread.c:464 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 8913 Comm: syz.3.1091 Not tainted 6.14.0-rc4-syzkaller-00242-g7a5668899f54 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:hlock_class kernel/locking/lockdep.c:230 [inline] RIP: 0010:check_wait_context kernel/locking/lockdep.c:4853 [inline] RIP: 0010:__lock_acquire+0x5bf/0x2100 kernel/locking/lockdep.c:5178 Code: 41 8b 1f 81 e3 ff 1f 00 00 48 89 d8 48 c1 e8 06 48 8d 3c c5 40 98 54 94 be 08 00 00 00 e8 c9 3d 8c 00 48 0f a3 1d 31 da b7 12 <73> 22 48 69 c3 c8 00 00 00 48 8d 98 00 17 ec 93 48 ba 00 00 00 00 RSP: 0018:ffffc90000a18930 EFLAGS: 00000057 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff819cbe07 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff94549840 RBP: 0000000000000002 R08: ffffffff94549847 R09: 1ffffffff28a9308 R10: dffffc0000000000 R11: fffffbfff28a9309 R12: ffff8880271a0ad4 R13: 000000000000000a R14: 1ffff11004e3416c R15: ffff8880271a0b60 FS: 00007f027e6646c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b3051fffc CR3: 000000007b662000 CR4: 0000000000350ef0 Call Trace: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 debug_object_deactivate+0x158/0x390 lib/debugobjects.c:873 debug_hrtimer_deactivate kernel/time/hrtimer.c:460 [inline] debug_deactivate+0x1b/0x220 kernel/time/hrtimer.c:502 __run_hrtimer kernel/time/hrtimer.c:1769 [inline] __hrtimer_run_queues+0x305/0xd30 kernel/time/hrtimer.c:1865 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1927 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x112/0x420 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+0xd8/0x140 kernel/locking/spinlock.c:194 Code: 9c 8f 44 24 20 42 80 3c 23 00 74 08 4c 89 f7 e8 be d3 1d f6 f6 44 24 21 02 75 52 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 53 3d 84 f5 65 8b 05 c4 b0 f8 73 85 c0 74 43 48 c7 04 24 0e 36 RSP: 0018:ffffc90003347ba0 EFLAGS: 00000206 RAX: 5edd81037a6c9500 RBX: 1ffff92000668f78 RCX: ffffffff819d2afa RDX: dffffc0000000000 RSI: ffffffff8c2aa4a0 RDI: 0000000000000001 RBP: ffffc90003347c30 R08: ffffffff94549847 R09: 1ffffffff28a9308 R10: dffffc0000000000 R11: fffffbfff28a9309 R12: dffffc0000000000 R13: 1ffff92000668f74 R14: ffffc90003347bc0 R15: 0000000000000246 clock_was_set+0x686/0x810 kernel/time/hrtimer.c:984 do_settimeofday64+0x343/0x5e0 kernel/time/timekeeping.c:1381 __do_sys_clock_settime kernel/time/posix-timers.c:1135 [inline] __se_sys_clock_settime kernel/time/posix-timers.c:1119 [inline] __x64_sys_clock_settime+0x23c/0x280 kernel/time/posix-timers.c:1119 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f027d78d169 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:00007f027e664038 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3 RAX: ffffffffffffffda RBX: 00007f027d9a5fa0 RCX: 00007f027d78d169 RDX: 0000000000000000 RSI: 0000400000000240 RDI: 0000000000000000 RBP: 00007f027d80e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f027d9a5fa0 R15: 00007ffd84359208