rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P17434/1:b..l P2/1:b..l rcu: (detected by 0, t=10502 jiffies, g=74585, q=449 ncpus=2) task:kthreadd state:R running task stack:24952 pid:2 tgid:2 ppid:0 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5397 [inline] __schedule+0x116a/0x5dd0 kernel/sched/core.c:6786 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7109 irqentry_exit+0x36/0x90 kernel/entry/common.c:307 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:56 [inline] RIP: 0010:stack_access_ok+0x53/0x200 arch/x86/kernel/unwind_orc.c:393 Code: 83 ec 08 80 3c 02 00 0f 85 94 01 00 00 4c 8d 6b 10 4c 8b 7b 08 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 80 3c 02 00 <0f> 85 52 01 00 00 48 89 da 48 8b 4b 10 48 b8 00 00 00 00 00 fc ff RSP: 0018:ffffc90000077560 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: ffffc90000077610 RCX: ffffffff914d86e8 RDX: 1ffff9200000eec4 RSI: ffffc90000077848 RDI: ffffc90000077610 RBP: ffffc90000077848 R08: ffffffff914d86ec R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000012b2c R12: 0000000000000008 R13: ffffc90000077620 R14: ffffc90000077618 R15: ffffc90000070000 deref_stack_reg arch/x86/kernel/unwind_orc.c:403 [inline] unwind_next_frame+0xb7d/0x20a0 arch/x86/kernel/unwind_orc.c:585 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x160/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x84/0x1a0 mm/page_owner.c:308 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1248 [inline] __free_frozen_pages+0x7fe/0x1180 mm/page_alloc.c:2706 discard_slab mm/slub.c:2717 [inline] __put_partials+0x16d/0x1c0 mm/slub.c:3186 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4148 [inline] slab_alloc_node mm/slub.c:4197 [inline] kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4204 prepare_creds+0x2c/0x7d0 kernel/cred.c:212 copy_creds+0xa7/0xa50 kernel/cred.c:312 copy_process+0xff6/0x7650 kernel/fork.c:2033 kernel_clone+0xfc/0x960 kernel/fork.c:2599 kernel_thread+0xd4/0x120 kernel/fork.c:2661 create_kthread kernel/kthread.c:487 [inline] kthreadd+0x503/0x800 kernel/kthread.c:847 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 task:kworker/u8:12 state:R running task stack:28968 pid:17434 tgid:17434 ppid:7188 task_flags:0x8040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5397 [inline] __schedule+0x116a/0x5dd0 kernel/sched/core.c:6786 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7109 irqentry_exit+0x36/0x90 kernel/entry/common.c:307 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_release+0x183/0x2f0 kernel/locking/lockdep.c:5896 Code: 0f c1 05 48 bd 37 12 83 f8 01 0f 85 1d 01 00 00 9c 58 f6 c4 02 0f 85 08 01 00 00 41 f7 c5 00 02 00 00 74 01 fb 48 8b 44 24 10 <65> 48 2b 05 5d 7b 37 12 0f 85 58 01 00 00 48 83 c4 18 5b 41 5c 41 RSP: 0018:ffffc900031875d8 EFLAGS: 00000206 RAX: e44c77d9ed4bf000 RBX: ffffffff8e5c4e00 RCX: ffffc900031875e4 RDX: 0000000000000001 RSI: ffffffff8de0aca5 RDI: ffffffff8c1573e0 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 000000000001214f R12: ffffffff816adac4 R13: 0000000000000206 R14: ffff88802667c880 R15: 0000000000000002 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] class_rcu_destructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0x3f9/0x20a0 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x160/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x84/0x1a0 mm/page_owner.c:308 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1248 [inline] __free_frozen_pages+0x7fe/0x1180 mm/page_alloc.c:2706 discard_slab mm/slub.c:2717 [inline] __put_partials+0x16d/0x1c0 mm/slub.c:3186 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4148 [inline] slab_alloc_node mm/slub.c:4197 [inline] kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4204 alloc_empty_file+0x55/0x1e0 fs/file_table.c:234 path_openat+0xda/0x2cb0 fs/namei.c:4041 do_filp_open+0x20b/0x470 fs/namei.c:4082 do_open_execat+0xf9/0x380 fs/exec.c:783 alloc_bprm+0x2d/0x6f0 fs/exec.c:1410 kernel_execve+0xb0/0x3b0 fs/exec.c:1885 call_usermodehelper_exec_async+0x255/0x4c0 kernel/umh.c:109 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread starved for 10349 jiffies! g74585 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 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:27672 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5397 [inline] __schedule+0x116a/0x5dd0 kernel/sched/core.c:6786 __schedule_loop kernel/sched/core.c:6864 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6879 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2256 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.16.0-rc7-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: 6b 6d 02 e9 83 fb 02 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 43 89 23 00 fb f4 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffffff8e207e08 EFLAGS: 000002c6 RAX: 00000000085c5123 RBX: 0000000000000000 RCX: ffffffff8b868c99 RDX: 0000000000000000 RSI: ffffffff8de2ff26 RDI: ffffffff8c1573e0 RBP: fffffbfff1c52ef0 R08: 0000000000000001 R09: ffffed1017086645 R10: ffff8880b843322b R11: 0000000000000001 R12: 0000000000000000 R13: ffffffff8e297780 R14: ffffffff90a94050 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124720000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055555b9435c8 CR3: 000000006bd84000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:749 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:185 [inline] do_idle+0x391/0x510 kernel/sched/idle.c:325 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:423 rest_init+0x16b/0x2b0 init/main.c:745 start_kernel+0x3ee/0x4d0 init/main.c:1102 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:307 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:288 common_startup_64+0x13e/0x148