rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P16235/1:b..l rcu: (detected by 0, t=10503 jiffies, g=175497, q=781 ncpus=2) task:syz-executor state:R running task stack:22304 pid:16235 tgid:16235 ppid:16230 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x17b4/0x5680 kernel/sched/core.c:7188 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7512 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline] irqentry_exit+0x14f/0x730 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_release+0x2d7/0x3c0 kernel/locking/lockdep.c:5893 Code: 06 9f 11 00 00 00 00 eb b5 e8 05 a6 16 0a f7 c3 00 02 00 00 74 b9 65 48 8b 05 f5 c0 9e 11 48 3b 44 24 28 75 44 fb 48 83 c4 30 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 1a 96 19 0a cc 48 8d 3d 32 dc 94 RSP: 0018:ffffc9000dc777a0 EFLAGS: 00000286 RAX: d831b4cb75a79b00 RBX: 0000000000000202 RCX: 0000000000000046 RDX: 0000000000000001 RSI: ffffffff8e24e50c RDI: ffffffff8c289ee0 RBP: ffff88801ffb8bb8 R08: ffffc9000dc778f8 R09: 0000000000000000 R10: ffffc9000dc77958 R11: fffff52001b8ef2d R12: 0000000000000001 R13: 0000000000000001 R14: ffffffff8e95cce0 R15: ffff88801ffb8000 rcu_lock_release include/linux/rcupdate.h:310 [inline] rcu_read_unlock include/linux/rcupdate.h:869 [inline] class_rcu_destructor include/linux/rcupdate.h:1181 [inline] unwind_next_frame+0x1bba/0x2550 arch/x86/kernel/unwind_orc.c:709 __unwind_start+0x5b8/0x760 arch/x86/kernel/unwind_orc.c:787 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe3/0x150 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 mm/page_owner.c:165 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1402 [inline] __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2943 __slab_free+0x274/0x2c0 mm/slub.c:5608 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4569 [inline] slab_alloc_node mm/slub.c:4898 [inline] kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4905 alloc_filename fs/namei.c:142 [inline] do_getname+0x2e/0x250 fs/namei.c:182 getname_flags fs/namei.c:225 [inline] class_filename_flags_constructor include/linux/fs.h:2555 [inline] user_path_at+0x2a/0x160 fs/namei.c:3642 ksys_umount fs/namespace.c:2062 [inline] __do_sys_umount fs/namespace.c:2070 [inline] __se_sys_umount fs/namespace.c:2068 [inline] __x64_sys_umount+0xf6/0x170 fs/namespace.c:2068 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff6dc19da57 RSP: 002b:00007ff6dc53ecb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: ffffffffffffffda RBX: 00007ff6dc232048 RCX: 00007ff6dc19da57 RDX: 0000000000000004 RSI: 0000000000000009 RDI: 00007ff6dc53fe00 RBP: 00007ff6dc53fdec R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff6dc53fe00 R13: 00007ff6dc232048 R14: 0000000000109646 R15: 00007ff6dc53fe40 rcu: rcu_preempt kthread timer wakeup didn't happen for 10502 jiffies! g175497 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=87300 rcu: rcu_preempt kthread starved for 10503 jiffies! g175497 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:26880 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x17b4/0x5680 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0x164/0x360 kernel/sched/core.c:7282 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 24548 Comm: syz.1.4705 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:num_possible_cpus include/linux/cpumask.h:1222 [inline] RIP: 0010:mm_get_cid kernel/sched/sched.h:3880 [inline] RIP: 0010:sched_mm_cid_fork+0x657/0x10e0 kernel/sched/core.c:10953 Code: c7 03 00 00 00 40 e9 19 01 00 00 49 c7 c4 b8 ae 29 8e 49 c1 ec 03 41 bd 00 00 00 80 eb 0a 89 e8 f7 d8 0f 81 09 fe ff ff f3 90 <48> b8 00 00 00 00 00 fc ff df 41 0f b6 04 04 84 c0 75 40 44 8b 35 RSP: 0018:ffffc90005d8fc48 EFLAGS: 00000887 RAX: 0000000080000000 RBX: ffff888033a079d0 RCX: 0000000080000001 RDX: dffffc0000000000 RSI: 0000000000000002 RDI: ffff888033a079d0 RBP: 0000000080000000 R08: 1ffff11006740de9 R09: 0000000000000000 R10: ffff888033a0708c R11: fffff52000bb1f78 R12: 1ffffffff1c535d7 R13: 0000000080000000 R14: 0000000000000002 R15: ffff888033a06e40 FS: 00007f5d52ea06c0(0000) GS:ffff888125314000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000002ef030 CR3: 0000000078796000 CR4: 00000000003526f0 Call Trace: bprm_execve+0xdb7/0x1440 fs/exec.c:1771 do_execveat_common+0x50d/0x690 fs/exec.c:1846 __do_sys_execveat fs/exec.c:1941 [inline] __se_sys_execveat fs/exec.c:1934 [inline] __x64_sys_execveat+0xc7/0xf0 fs/exec.c:1934 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5d51f9c819 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:00007f5d52ea0028 EFLAGS: 00000246 ORIG_RAX: 0000000000000142 RAX: ffffffffffffffda RBX: 00007f5d52215fa0 RCX: 00007f5d51f9c819 RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000004 RBP: 00007f5d52032c91 R08: 0000000000001000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5d52216038 R14: 00007f5d52215fa0 R15: 00007f5d5233fa48