rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P11835/1:b..l rcu: (detected by 0, t=10502 jiffies, g=147825, q=513 ncpus=1) task:syz-executor state:R running task stack:22576 pid:11835 tgid:11835 ppid:11827 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7556 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x8f0 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_release+0x2d7/0x3c0 kernel/locking/lockdep.c:5893 Code: 7d ca 11 00 00 00 00 eb b5 e8 55 9d 2e 0a f7 c3 00 02 00 00 74 b9 65 48 8b 05 45 38 ca 11 48 3b 44 24 28 75 44 fb 48 83 c4 30 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 15 49 6d ff cc 48 8d 3d a2 33 b8 RSP: 0018:ffffc90002e5f190 EFLAGS: 00000286 RAX: 7c5c641e84d17e00 RBX: 0000000000000206 RCX: 0000000000000046 RDX: 0000000000000003 RSI: ffffffff8e4b347b RDI: ffffffff8c4bdd80 RBP: ffff888035108c18 R08: ffffc90002e5f350 R09: ffffc90002e5f318 R10: dffffc0000000000 R11: fffff520005cbe65 R12: 0000000000000003 R13: 0000000000000003 R14: ffffffff8eb59c60 R15: ffff888035108000 rcu_lock_release include/linux/rcupdate.h:310 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] class_rcu_destructor include/linux/rcupdate.h:1183 [inline] unwind_next_frame+0x1baa/0x2550 arch/x86/kernel/unwind_orc.c:709 __unwind_start+0x514/0x660 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 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4584 [inline] slab_alloc_node mm/slub.c:4917 [inline] kmem_cache_alloc_noprof+0x2a0/0x5f0 mm/slub.c:4931 anon_vma_alloc mm/rmap.c:94 [inline] anon_vma_fork+0x88/0x540 mm/rmap.c:391 dup_mmap+0x970/0x1d90 mm/mmap.c:1803 dup_mm kernel/fork.c:1543 [inline] copy_mm+0x11a/0x480 kernel/fork.c:1595 copy_process+0x1e3e/0x4390 kernel/fork.c:2289 kernel_clone+0x2d7/0x940 kernel/fork.c:2748 __do_sys_clone kernel/fork.c:2889 [inline] __se_sys_clone kernel/fork.c:2873 [inline] __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2873 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f49f69c6a92 RSP: 002b:00007ffdc9459430 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffdc9459430 RCX: 00007f49f69c6a92 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffdc94595bc R08: 0000000000000000 R09: 0000000000000001 R10: 000055555a4557d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 00000000000b0c01 R15: 00007ffdc9459610 rcu: rcu_preempt kthread starved for 10502 jiffies! g147825 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:27496 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 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: CPU: 0 UID: 0 PID: 32 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 RIP: 0010:finish_task_switch+0x417/0xc60 kernel/sched/core.c:5361 Code: 04 00 00 41 c7 84 24 20 0e 00 00 00 00 00 00 0f 1f 44 00 00 49 83 c4 48 4c 89 e7 e8 f3 ab 3e 0a e8 de ac 39 00 fb 4c 8b 65 c8 <49> 8d bc 24 f8 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 RSP: 0018:ffffc90000a879c0 EFLAGS: 00000202 RAX: 0000000000003f9b RBX: ffff8880b863bf20 RCX: 0000000080000001 RDX: 0000000000000000 RSI: ffffffff8e22e3c6 RDI: ffffffff8c4bdd80 RBP: ffffc90000a87a10 R08: ffffffff90579937 R09: 1ffffffff20af326 R10: dffffc0000000000 R11: fffffbfff20af327 R12: ffff88801f6d1f00 R13: ffff8880b863bee8 R14: dffffc0000000000 R15: 1ffff110170c77e4 FS: 0000000000000000(0000) GS:ffff888124f4d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000058 CR3: 0000000090b61000 CR4: 0000000000350ef0 Call Trace: context_switch kernel/sched/core.c:5513 [inline] __schedule+0x17e1/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 watchdog+0x91/0x1030 kernel/hung_task.c:565 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