rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P20675/1:b..l P21371/1:b..l rcu: (detected by 1, t=10502 jiffies, g=116637, q=845 ncpus=2) task:sed state:R running task stack:24872 pid:21371 tgid:21371 ppid:21370 task_flags:0x40000c flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1295/0x67a0 kernel/sched/core.c:7189 preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7370 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:190 spin_unlock include/linux/spinlock.h:390 [inline] zap_pte_range mm/memory.c:1948 [inline] zap_pmd_range mm/memory.c:2004 [inline] zap_pud_range mm/memory.c:2032 [inline] zap_p4d_range mm/memory.c:2053 [inline] __zap_vma_range+0x1791/0x4bf0 mm/memory.c:2093 unmap_vmas+0x299/0x5f0 mm/memory.c:2162 exit_mmap+0x1ef/0xa10 mm/mmap.c:1300 __mmput+0x12a/0x410 kernel/fork.c:1178 mmput+0x67/0x80 kernel/fork.c:1201 exit_mm kernel/exit.c:582 [inline] do_exit+0x8b2/0x2af0 kernel/exit.c:964 do_group_exit+0xd5/0x2a0 kernel/exit.c:1119 __do_sys_exit_group kernel/exit.c:1130 [inline] __se_sys_exit_group kernel/exit.c:1128 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1128 x64_sys_call+0x102c/0x1530 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd50a8a76c5 RSP: 002b:00007ffd24ea0e48 EFLAGS: 00000206 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007fd50a9a8fe8 RCX: 00007fd50a8a76c5 RDX: 00000000000000e7 RSI: ffffffffffffff88 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fd50a9a7680 R15: 00007fd50a9a9000 task:syz-executor state:R running task stack:23544 pid:20675 tgid:20675 ppid:20662 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1295/0x67a0 kernel/sched/core.c:7189 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x205/0x7e0 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x5e/0x370 kernel/locking/lockdep.c:5872 Code: 05 3b a2 26 12 83 f8 07 0f 87 d9 02 00 00 48 0f a3 05 46 40 f3 0e 0f 82 a4 02 00 00 8b 35 ce 73 f3 0e 85 f6 0f 85 bf 00 00 00 <48> 8b 44 24 30 65 48 2b 05 dd a1 26 12 0f 85 ed 02 00 00 48 83 c4 RSP: 0018:ffffc90004af72a0 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff8defcec5 RDI: ffffffff8c1c3a00 RBP: ffffffff8e7e5620 R08: 00000000875ba5a4 R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] class_rcu_constructor include/linux/rcupdate.h:1181 [inline] unwind_next_frame+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x162/0x1e0 mm/page_owner.c:165 __reset_page_owner+0x84/0x190 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_unref_folios+0xa0d/0x16f0 mm/page_alloc.c:3004 folios_put_refs+0x571/0xa90 mm/swap.c:1008 folio_batch_release include/linux/folio_batch.h:101 [inline] shmem_undo_range+0x5e5/0x1570 mm/shmem.c:1149 shmem_truncate_range mm/shmem.c:1277 [inline] shmem_evict_inode+0x3f3/0xc40 mm/shmem.c:1407 evict+0x3c2/0xad0 fs/inode.c:841 iput_final fs/inode.c:1960 [inline] iput.part.0+0x605/0xf50 fs/inode.c:2009 iput+0x35/0x40 fs/inode.c:1975 filename_unlinkat+0x466/0x730 fs/namei.c:5572 __do_sys_unlink fs/namei.c:5603 [inline] __se_sys_unlink fs/namei.c:5600 [inline] __x64_sys_unlink+0x46/0x70 fs/namei.c:5600 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f617e59bf47 RSP: 002b:00007ffd333537e8 EFLAGS: 00000206 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f617e59bf47 RDX: 00007ffd33353810 RSI: 00007ffd333538a0 RDI: 00007ffd333538a0 RBP: 00007ffd333538a0 R08: 00007ffd333548a0 R09: 00000000ffffffff R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffd33354930 R13: 00007f617e6321ca R14: 00000000000df645 R15: 00007ffd33354970 rcu: rcu_preempt kthread starved for 10496 jiffies! g116637 f0x0 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:28360 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1295/0x67a0 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7283 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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: 1 UID: 0 PID: 5611 Comm: syz-executor Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x589/0x1700 kernel/smp.c:892 Code: b8 00 00 00 00 00 fc ff df 48 8b 54 24 08 49 89 d5 49 89 d4 49 c1 ed 03 41 83 e4 07 49 01 c5 41 83 c4 03 e8 39 83 0c 00 f3 90 <41> 0f b6 45 00 41 38 c4 7c 08 84 c0 0f 85 63 0f 00 00 8b 45 08 31 RSP: 0018:ffffc9000393f618 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81fc2bed RDX: ffff88802e722500 RSI: ffffffff81fc2bc7 RDI: ffff88802e722500 RBP: ffff8880b8443320 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed1017088665 R14: 0000000000000001 R15: ffff8880b853c5c0 FS: 00005555578d5500(0000) GS:ffff88812446d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3fc35456b8 CR3: 000000005a882000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1057 __flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x45f/0x16f0 arch/x86/mm/tlb.c:1451 dup_mmap+0x12e8/0x2180 mm/mmap.c:1905 dup_mm kernel/fork.c:1534 [inline] copy_mm kernel/fork.c:1586 [inline] copy_process+0x6c78/0x7ed0 kernel/fork.c:2264 kernel_clone+0x12e/0x9c0 kernel/fork.c:2721 __do_sys_clone+0xd9/0x120 kernel/fork.c:2862 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3fc27c58d2 Code: 89 e7 e8 71 8b f7 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffc26f4b7d0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffc26f4b7d0 RCX: 00007f3fc27c58d2 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffc26f4b95c R08: 0000000000000000 R09: 0000000000000001 R10: 00005555578d57d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 00000000000e041c R15: 00007ffc26f4b9b0