rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P10416/2:b..l P5803/1:b..l rcu: (detected by 1, t=10502 jiffies, g=25929, q=826 ncpus=2) task:syz-executor state:R running task stack:20848 pid:5803 tgid:5803 ppid:5798 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1480/0x50a0 kernel/sched/core.c:6863 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7190 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:rcu_is_watching+0x0/0xb0 kernel/rcu/tree.c:747 Code: c7 c7 40 3b 5b 8d e8 df b1 0e 03 eb cc 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 41 57 41 56 53 65 ff 05 e0 d0 06 10 e8 6b ae 20 09 89 RSP: 0018:ffffc90004b3f6c0 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffff8880b8843f30 RCX: ffff888026f40000 RDX: 000000005f479b93 RSI: ffffffff8cfd2d20 RDI: ffffffff8b3edde0 RBP: 0000000000000002 R08: ffffffff8ac8f451 R09: ffffffff8d5aecc0 R10: 0000000000000000 R11: fffffbfff1db4b0f R12: 1ffff11004de8090 R13: ffff888026f40000 R14: ffff888026f40480 R15: dffffc0000000000 rcu_read_unlock include/linux/rcupdate.h:895 [inline] rt_spin_unlock+0x114/0x200 kernel/locking/spinlock_rt.c:82 spin_unlock include/linux/spinlock_rt.h:105 [inline] ___slab_alloc+0x87a/0x1400 mm/slub.c:4550 __slab_alloc+0xc6/0x1f0 mm/slub.c:4774 __slab_alloc_node mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:5246 [inline] kmem_cache_alloc_noprof+0x101/0x6c0 mm/slub.c:5265 lsm_file_alloc security/security.c:169 [inline] security_file_alloc+0x34/0x330 security/security.c:2380 init_file+0x99/0x310 fs/file_table.c:159 alloc_empty_file+0x6e/0x1d0 fs/file_table.c:241 path_openat+0x10e/0x3df0 fs/namei.c:4773 do_filp_open+0x1fa/0x410 fs/namei.c:4814 do_sys_openat2+0x121/0x200 fs/open.c:1430 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1447 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1f1f8bf041 RSP: 002b:00007ffc20debab0 EFLAGS: 00000287 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f1f1f943d7d RCX: 00007f1f1f8bf041 RDX: 0000000000090800 RSI: 00007ffc20decc60 RDI: 00000000ffffff9c RBP: 00007ffc20decc4c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000287 R12: 00007ffc20decc60 R13: 00007f1f1f943d7d R14: 0000000000098096 R15: 00007ffc20decca0 task:syz.4.1369 state:R running task stack:25440 pid:10416 tgid:10414 ppid:5807 task_flags:0x40044c flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1480/0x50a0 kernel/sched/core.c:6863 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7190 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:addr_has_metadata mm/kasan/kasan.h:333 [inline] RIP: 0010:check_region_inline mm/kasan/generic.c:188 [inline] RIP: 0010:kasan_check_range+0x47/0x2c0 mm/kasan/generic.c:200 Code: 49 39 f8 0f 82 82 02 00 00 49 b9 00 00 00 00 00 80 ff ff eb 11 cc cc cc f3 0f 1e fa 49 b9 00 00 00 00 00 00 00 ff f3 0f 1e fa <4c> 39 cf 0f 82 58 02 00 00 49 89 ff 49 c1 ef 03 49 ba 00 00 00 00 RSP: 0018:ffffc9000548f330 EFLAGS: 00000202 RAX: ffffffff81fcff01 RBX: ffffea0000fade40 RCX: ffffffff81fcff64 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffea0000fade40 RBP: 1ffffd40001f5bc9 R08: ffffea0000fade48 R09: ffff800000000000 R10: dffffc0000000000 R11: fffff940001f5bc9 R12: 0000000000000000 R13: 1ffffd40001f5bc8 R14: ffffea0000fade48 R15: 0000000000000004 instrument_atomic_read include/linux/instrumented.h:68 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] folio_test_unevictable include/linux/page-flags.h:643 [inline] folio_mark_accessed+0x174/0x4a0 mm/swap.c:466 zap_present_folio_ptes mm/memory.c:1635 [inline] zap_present_ptes mm/memory.c:1708 [inline] do_zap_pte_range mm/memory.c:1810 [inline] zap_pte_range mm/memory.c:1854 [inline] zap_pmd_range mm/memory.c:1946 [inline] zap_pud_range mm/memory.c:1975 [inline] zap_p4d_range mm/memory.c:1996 [inline] unmap_page_range+0x1919/0x3ce0 mm/memory.c:2017 unmap_single_vma mm/memory.c:2059 [inline] unmap_vmas+0x399/0x580 mm/memory.c:2101 exit_mmap+0x239/0xb10 mm/mmap.c:1277 __mmput+0xcb/0x3d0 kernel/fork.c:1130 exit_mm+0x1da/0x2c0 kernel/exit.c:583 do_exit+0x658/0x2310 kernel/exit.c:961 do_group_exit+0x21c/0x2d0 kernel/exit.c:1114 get_signal+0x125d/0x1310 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop+0x87/0x4f0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2e3/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f16ecc9f34b RSP: 002b:00007f16eaefbf10 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: fffffffffffffffc RBX: 0000000000000003 RCX: 00007f16ecc9f34b RDX: 00007f16eaefcfe0 RSI: 0000000080085502 RDI: 0000000000000003 RBP: 00007f16eaefcfe0 R08: 0000000000000080 R09: 00007f16eaefbfd8 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000080085502 R13: 0000000800000000 R14: 0000000000000012 R15: 00007f16ecd2f52a rcu: rcu_preempt kthread timer wakeup didn't happen for 10483 jiffies! g25929 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=29570 rcu: rcu_preempt kthread starved for 10484 jiffies! g25929 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:21688 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1480/0x50a0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 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+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 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 syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: 53 c9 03 00 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 53 b6 21 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8d207d80 EFLAGS: 000002c6 RAX: 3b832614d57a7b00 RBX: ffffffff8196311a RCX: 3b832614d57a7b00 RDX: 0000000000000001 RSI: ffffffff8cdfbf93 RDI: ffffffff8b3edde0 RBP: ffffffff8d207ea8 R08: ffff8880b8833c5b R09: 1ffff1101710678b R10: dffffc0000000000 R11: ffffed101710678c R12: ffffffff8eda5870 R13: 1ffffffff1a60650 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888126d52000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000008000 CR3: 000000003c7c0000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1ea/0x520 kernel/sched/idle.c:332 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430 rest_init+0x2de/0x300 init/main.c:757 start_kernel+0x3ae/0x410 init/main.c:1111 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147