rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5845/1:b..l rcu: (detected by 1, t=10502 jiffies, g=49997, q=1180603 ncpus=2) task:syz-executor state:R running task stack:21576 pid:5845 tgid:5845 ppid:5844 task_flags:0x400100 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288 irqentry_exit+0x6f/0x90 kernel/entry/common.c:197 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline] RIP: 0010:lock_acquire+0x61/0x360 kernel/locking/lockdep.c:5831 Code: 24 58 0f 1f 44 00 00 65 8b 05 5f 75 03 11 83 f8 08 0f 83 b8 01 00 00 89 c0 48 0f a3 05 48 3c 06 0e 73 16 e8 61 02 09 00 84 c0 <75> 0d f6 05 75 21 f0 0d 01 0f 84 d7 01 00 00 83 3d 59 6d 06 0e 00 RSP: 0018:ffffc90002ff75f8 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 459baeac7f122800 RDX: 0000000000000000 RSI: ffffffff8be33f60 RDI: ffffffff8be33f20 RBP: ffffffff8172d195 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: ffffffff81ac4860 R12: 0000000000000002 R13: ffffffff8e13a120 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf5/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:308 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2895 discard_slab mm/slub.c:2758 [inline] __put_partials+0x156/0x1a0 mm/slub.c:3223 put_cpu_partial+0x17c/0x250 mm/slub.c:3298 __slab_free+0x2d5/0x3c0 mm/slub.c:4565 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:340 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4191 [inline] slab_alloc_node mm/slub.c:4240 [inline] kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4247 lsm_inode_alloc security/security.c:755 [inline] security_inode_alloc+0x39/0x330 security/security.c:1697 inode_init_always_gfp+0x9ed/0xdc0 fs/inode.c:306 inode_init_always include/linux/fs.h:3309 [inline] alloc_inode+0x82/0x1b0 fs/inode.c:353 new_inode_pseudo include/linux/fs.h:3392 [inline] get_pipe_inode fs/pipe.c:886 [inline] create_pipe_files+0x51/0x7e0 fs/pipe.c:926 __do_pipe_flags+0x46/0x1f0 fs/pipe.c:988 do_pipe2+0x9c/0x170 fs/pipe.c:1036 __do_sys_pipe2 fs/pipe.c:1054 [inline] __se_sys_pipe2 fs/pipe.c:1052 [inline] __x64_sys_pipe2+0x5a/0x70 fs/pipe.c:1052 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f673a58dbe9 RSP: 002b:00007ffda6b02ce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000125 RAX: ffffffffffffffda RBX: 0000555564b17950 RCX: 00007f673a58dbe9 RDX: 0000000000000007 RSI: 0000000000000000 RDI: 00007ffda6b02d00 RBP: 00007ffda6b030b0 R08: 0000000000000007 R09: 0000555564b2bd10 R10: f822d6f98910417c R11: 0000000000000246 R12: 0000555564b17b20 R13: 0000555564b1c088 R14: 00007ffda6b02e30 R15: 0000555564b164c0 rcu: rcu_preempt kthread starved for 470 jiffies! g49997 f0x2 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:27224 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x439/0x7d0 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: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: 3e bd 95 f5 cc cc cc 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 b3 a9 0d 00 f3 0f 1e fa fb f4 13 bd 95 f5 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197de0 EFLAGS: 000002c2 RAX: 39f9f393b6e0a600 RBX: ffffffff81969528 RCX: 39f9f393b6e0a600 RDX: 0000000000000001 RSI: ffffffff8d9ba5a7 RDI: ffffffff8be33f80 RBP: ffffc90000197f20 R08: ffff8880b8732f9b R09: 1ffff110170e65f3 R10: dffffc0000000000 R11: ffffed10170e65f4 R12: ffffffff8fa3a730 R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff110039d9b40 FS: 0000000000000000(0000) GS:ffff888125d12000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb487c0c1d4 CR3: 0000000044f21000 CR4: 0000000000350ef0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:757 default_idle_call+0x74/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x1e8/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x147