rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5849/1:b..l P5207/1:b..l rcu: (detected by 1, t=10502 jiffies, g=13033, q=225 ncpus=2) task:udevd state:R running task stack:21856 pid:5207 tgid:5207 ppid:1 task_flags:0x400140 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0x190e/0x4c90 kernel/sched/core.c:6765 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7087 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:stack_trace_consume_entry+0x6a/0x280 kernel/stacktrace.c:89 Code: 89 ec 49 c1 ec 03 41 0f b6 04 14 84 c0 0f 85 1a 01 00 00 44 3b 45 00 73 3c 48 8d 7b 0c 49 89 fd 49 c1 ed 03 41 0f b6 44 15 00 <84> c0 0f 85 36 01 00 00 44 8b 37 45 85 f6 74 22 41 ff ce 41 0f b6 RSP: 0018:ffffc90003187890 EFLAGS: 00000a07 RAX: 0000000000000000 RBX: ffffc900031879c0 RCX: ffffffff919df000 RDX: dffffc0000000000 RSI: ffffffff821d8bb9 RDI: ffffc900031879cc RBP: ffffc900031879c8 R08: 0000000000000007 R09: ffffc900031879d0 R10: ffffc90003187930 R11: ffffffff81ad5ae0 R12: 1ffff92000630f39 R13: 1ffff92000630f39 R14: ffffc900031879c0 R15: 1ffff92000630f3a arch_stack_walk+0x10e/0x150 arch/x86/kernel/stacktrace.c:27 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122 save_stack+0xfb/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x76/0x430 mm/page_owner.c:297 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1127 [inline] free_frozen_pages+0xe0d/0x10e0 mm/page_alloc.c:2660 discard_slab mm/slub.c:2684 [inline] __put_partials+0x160/0x1c0 mm/slub.c:3153 put_cpu_partial+0x17c/0x250 mm/slub.c:3228 __slab_free+0x290/0x380 mm/slub.c:4479 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4115 [inline] slab_alloc_node mm/slub.c:4164 [inline] kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4171 getname_flags+0xb7/0x540 fs/namei.c:139 getname fs/namei.c:223 [inline] __do_sys_unlink fs/namei.c:4637 [inline] __se_sys_unlink fs/namei.c:4635 [inline] __x64_sys_unlink+0x3a/0x50 fs/namei.c:4635 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: 0033:0x7fc110317da7 RSP: 002b:00007ffef07fef08 EFLAGS: 00000202 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 00007ffef07ff000 RCX: 00007fc110317da7 RDX: 0000000000000000 RSI: 000000000bdc7fc0 RDI: 00005643949c40d8 RBP: 0000000000000000 R08: 000000000bead635 R09: 7fffffffffffffff R10: 00007fc1107c6038 R11: 0000000000000202 R12: 0000000000000bb8 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 task:syz-executor state:R running task stack:19896 pid:5849 tgid:5849 ppid:1 task_flags:0x40054c flags:0x00004004 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: 0033:0x7f92a09833d7 RSP: 002b:00007f92a0ccfd80 EFLAGS: 00000293 ORIG_RAX: 000000000000003d RAX: fffffffffffffe00 RBX: 0000000000000097 RCX: 00007f92a09833d7 RDX: 0000000040000000 RSI: 00007f92a0ccfdec RDI: 00000000ffffffff RBP: 00007f92a0ccfdec R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 000000000000002a R13: 0000555566243590 R14: 0000000000029111 R15: 00007f92a0ccfe40 rcu: rcu_preempt kthread starved for 9451 jiffies! g13033 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: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+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/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: CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.14.0-rc5-syzkaller-00023-gbb2281fb05e5 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline] RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:92 [inline] RIP: 0010:acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:112 Code: 90 90 90 90 90 90 90 90 90 65 48 8b 04 25 80 d6 03 00 48 f7 00 08 00 00 00 75 10 66 90 0f 00 2d 05 f0 81 00 f3 0f 1e fa fb f4 c3 cc cc cc cc 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 RSP: 0018:ffffc900001a7d08 EFLAGS: 00000246 RAX: ffff88801d2e8000 RBX: ffff888144281064 RCX: 000000000010e729 RDX: 0000000000000001 RSI: ffff888144281000 RDI: ffff888144281064 RBP: 000000000003aab8 R08: ffff8880b873799b R09: 1ffff110170e6f33 R10: dffffc0000000000 R11: ffffffff8c08a010 R12: ffff8881405d4000 R13: 0000000000000001 R14: 0000000000000001 R15: ffffffff8f3381e0 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005555756bc5c8 CR3: 00000000227aa000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: acpi_idle_enter+0xe4/0x140 drivers/acpi/processor_idle.c:699 cpuidle_enter_state+0x109/0x470 drivers/cpuidle/cpuidle.c:268 cpuidle_enter+0x5d/0xa0 drivers/cpuidle/cpuidle.c:389 call_cpuidle kernel/sched/idle.c:155 [inline] cpuidle_idle_call kernel/sched/idle.c:230 [inline] do_idle+0x372/0x5c0 kernel/sched/idle.c:325 cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:423 start_secondary+0x102/0x110 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x147