rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7671/1:b..l rcu: (detected by 1, t=10502 jiffies, g=15177, q=1031 ncpus=2) task:syz.0.390 state:R running task stack:26400 pid:7671 tgid:7659 ppid:5821 task_flags:0x400140 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7090 irqentry_exit+0x36/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x62/0x350 kernel/locking/lockdep.c:5870 Code: b1 0e 12 83 f8 07 0f 87 bc 02 00 00 89 c0 48 0f a3 05 22 34 ee 0e 0f 82 74 02 00 00 8b 35 9a 63 ee 0e 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 f9 b0 0e 12 0f 85 c7 02 00 00 48 83 c4 RSP: 0018:ffffc9001bc9f1b0 EFLAGS: 00000206 RAX: 0000000000000046 RBX: ffffffff8e3c1580 RCX: 00000000a07923a3 RDX: 0000000000000000 RSI: ffffffff8dbc95df RDI: ffffffff8bf46580 RBP: 0000000000000002 R08: 22dd6caee5500fac R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 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+0xd1/0x20a0 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:1262 [inline] free_unref_folios+0x999/0x1630 mm/page_alloc.c:2737 folios_put_refs+0x56f/0x740 mm/swap.c:992 folio_batch_release include/linux/pagevec.h:101 [inline] mapping_try_invalidate+0x2fd/0x3c0 mm/truncate.c:550 drop_pagecache_sb+0xe2/0x2a0 fs/drop_caches.c:40 iterate_supers+0xfb/0x240 fs/super.c:934 drop_caches_sysctl_handler fs/drop_caches.c:64 [inline] drop_caches_sysctl_handler+0xeb/0x190 fs/drop_caches.c:51 proc_sys_call_handler+0x3bf/0x5c0 fs/proc/proc_sysctl.c:601 do_iter_readv_writev+0x654/0x950 fs/read_write.c:825 vfs_writev+0x353/0xdc0 fs/read_write.c:1055 do_writev+0x132/0x330 fs/read_write.c:1101 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc94df8d169 RSP: 002b:00007fc94ee72038 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 00007fc94e1a6080 RCX: 00007fc94df8d169 RDX: 0000000000000002 RSI: 0000200000000080 RDI: 0000000000000005 RBP: 00007fc94e00e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fc94e1a6080 R15: 00007ffc858c1718 rcu: rcu_preempt kthread starved for 10547 jiffies! g15177 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:27704 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6860 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2046 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2248 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.14.0-syzkaller-13423-ga8662bcd2ff1 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:81 Code: 95 5d 02 c3 cc cc cc cc 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 d3 bc 17 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:ffffffff8e007e10 EFLAGS: 000002c6 RAX: 0000000000d737e3 RBX: 0000000000000000 RCX: ffffffff8b723439 RDX: 0000000000000000 RSI: ffffffff8dbeeb53 RDI: ffffffff8bf46580 RBP: fffffbfff1c12ee8 R08: 0000000000000001 R09: ffffed10170865bd R10: ffff8880b8432deb R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff8e097740 R14: ffffffff90865310 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881249b3000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055694d7ef060 CR3: 000000002a0ae000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:748 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:743 start_kernel+0x3e9/0x4d0 init/main.c:1099 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:513 x86_64_start_kernel+0xb0/0xc0 arch/x86/kernel/head64.c:494 common_startup_64+0x13e/0x148