rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8419/1:b..l P8306/1:b..l P8437/1:b..l rcu: (detected by 1, t=10502 jiffies, g=36037, q=279 ncpus=2) task:syz.2.829 state:R running task stack:25960 pid:8437 tgid:8435 ppid:5621 task_flags:0x400040 flags:0x00080002 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:476 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [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:__update_page_owner_handle+0x111/0x550 mm/page_owner.c:256 Code: 74 24 0a bf 1f 00 00 00 e8 7c d0 87 ff 66 83 fb 1f 0f 87 31 0d a4 fe 41 bf 01 00 00 00 44 89 e1 48 c7 c0 a0 e3 1d 9b 45 31 f6 <41> d3 e7 48 c1 e8 03 49 bd 00 00 00 00 00 fc ff df 48 89 44 24 30 RSP: 0018:ffffc90005086e88 EFLAGS: 00000246 RAX: ffffffff9b1de3a0 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 000000000000001f RDI: ffff88807da58000 RBP: ffff88801d90b3a0 R08: 0000000000000003 R09: 000000000000001f R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 1ffff92000a10de7 R14: 0000000000000000 R15: 0000000000000001 __set_page_owner+0x11f/0x540 mm/page_owner.c:342 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x153/0x170 mm/page_alloc.c:1858 prep_new_page mm/page_alloc.c:1866 [inline] get_page_from_freelist+0x11a6/0x33b0 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x27c/0x2bc0 mm/page_alloc.c:5226 alloc_pages_mpol+0x1fb/0x540 mm/mempolicy.c:2490 folio_alloc_mpol_noprof+0x36/0x260 mm/mempolicy.c:2509 vma_alloc_folio_noprof+0xed/0x1d0 mm/mempolicy.c:2544 folio_prealloc mm/memory.c:1191 [inline] wp_page_copy mm/memory.c:3859 [inline] do_wp_page+0xd75/0x4350 mm/memory.c:4320 handle_pte_fault mm/memory.c:6427 [inline] __handle_mm_fault+0x1ab6/0x2a00 mm/memory.c:6549 handle_mm_fault+0x36d/0xa20 mm/memory.c:6718 do_user_addr_fault+0x74c/0x12f0 arch/x86/mm/fault.c:1385 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0010:__put_user_nocheck_4+0x3/0x10 arch/x86/lib/putuser.S:104 Code: d9 0f 01 cb 89 01 31 c9 0f 01 ca e9 c7 d7 03 00 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 01 cb <89> 01 31 c9 0f 01 ca c3 cc cc cc cc 90 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc900050879d8 EFLAGS: 00050246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000200000352030 RDX: 0000000000080000 RSI: ffffffff8955e241 RDI: ffff88807da58000 RBP: ffffc90005087d78 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000000 R12: 0000000000000000 R13: 0000200000352000 R14: ffffc90005087dbc R15: 0000000000000002 ____sys_recvmsg+0x2ec/0x640 net/socket.c:2931 ___sys_recvmsg+0x16a/0x1a0 net/socket.c:2960 do_recvmmsg+0x301/0x760 net/socket.c:3055 __sys_recvmmsg net/socket.c:3129 [inline] __do_sys_recvmmsg net/socket.c:3152 [inline] __se_sys_recvmmsg net/socket.c:3145 [inline] __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3145 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: 0033:0x7f7249b9ce59 RSP: 002b:00007f724aa43028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f7249e16090 RCX: 00007f7249b9ce59 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000003 RBP: 00007f7249c32d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f7249e16128 R14: 00007f7249e16090 R15: 00007ffe62b198b8 task:syz.1.791 state:R running task stack:23688 pid:8306 tgid:8306 ppid:5608 task_flags:0x40064c flags:0x00080001 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:476 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [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:lockdep_enabled kernel/locking/lockdep.c:124 [inline] RIP: 0010:lock_is_held_type+0x42/0x140 kernel/locking/lockdep.c:5933 Code: 8b 15 aa 96 80 08 85 d2 0f 85 de 00 00 00 41 57 41 56 41 55 41 54 55 53 48 83 ec 08 65 48 8b 2d 1c 4f 80 08 8b 95 8c 0b 00 00 <85> d2 0f 85 a7 00 00 00 48 89 fb 41 89 f4 9c 41 5d fa 48 c7 c7 29 RSP: 0018:ffffc900050e7240 EFLAGS: 00000282 RAX: 00000000ffffffff RBX: ffffea00012fe2c0 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffff888058eab9c0 RBP: ffff888033420000 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffea00012fe2c0 R13: ffff888057e4d8c0 R14: 0000000000000001 R15: dffffc0000000000 lock_is_held include/linux/lockdep.h:249 [inline] xa_entry include/linux/xarray.h:1226 [inline] xas_reload include/linux/xarray.h:1624 [inline] find_get_entry mm/filemap.c:2085 [inline] find_lock_entries+0x841/0x1190 mm/filemap.c:2172 shmem_undo_range+0x212/0x1570 mm/shmem.c:1131 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 dentry_unlink_inode+0x2c0/0x4c0 fs/dcache.c:476 __dentry_kill+0x1d0/0x690 fs/dcache.c:718 finish_dput+0x76/0x480 fs/dcache.c:927 dput.part.0+0x456/0x570 fs/dcache.c:976 dput+0x1f/0x30 fs/dcache.c:968 __fput+0x519/0xb50 fs/file_table.c:518 task_work_run+0x150/0x240 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x951/0x2af0 kernel/exit.c:976 do_group_exit+0xd5/0x2a0 kernel/exit.c:1119 get_signal+0x20ff/0x2210 kernel/signal.c:3037 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop kernel/entry/common.c:98 [inline] __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:252 [inline] irqentry_exit_to_user_mode include/linux/irq-entry-common.h:323 [inline] irqentry_exit+0x410/0x7e0 kernel/entry/common.c:162 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f506e59ce61 RSP: 002b:fffffffffffffe70 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007f506e816090 RCX: 00007f506e59ce59 RDX: 0000000000000000 RSI: fffffffffffffe70 RDI: 0000000000008000 RBP: 00007f506e632d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f506e816128 R14: 00007f506e816090 R15: 00007fffc94d15d8 task:syz.2.823 state:R running task stack:23656 pid:8419 tgid:8419 ppid:5621 task_flags:0x400640 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:476 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [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:deref_stack_reg arch/x86/kernel/unwind_orc.c:419 [inline] RIP: 0010:unwind_next_frame+0x154c/0x2090 arch/x86/kernel/unwind_orc.c:677 Code: c2 40 0f 9e c6 84 d2 0f 95 c0 40 84 c6 0f 85 90 07 00 00 48 0f bf 69 02 ba 08 00 00 00 4c 89 ef 4d 8d 7d 34 4c 01 f5 48 89 ee cf e8 ff ff 84 c0 0f 84 f3 ed ff ff 48 89 ef e8 9f e2 ff ff 49 RSP: 0018:ffffc9000582e378 EFLAGS: 00000287 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff9182eb20 RDX: 0000000000000008 RSI: ffffc9000582ed88 RDI: ffffc9000582e3e8 RBP: ffffc9000582ed88 R08: 0000000000000001 R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000015188 R12: ffffc9000582e438 R13: ffffc9000582e3e8 R14: ffffc9000582edb8 R15: ffffc9000582e41c 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 __set_page_owner+0x8c/0x540 mm/page_owner.c:341 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x153/0x170 mm/page_alloc.c:1858 prep_new_page mm/page_alloc.c:1866 [inline] get_page_from_freelist+0x11a6/0x33b0 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x27c/0x2bc0 mm/page_alloc.c:5226 alloc_pages_mpol+0x1fb/0x540 mm/mempolicy.c:2490 folio_alloc_mpol_noprof+0x36/0x260 mm/mempolicy.c:2509 shmem_alloc_folio+0x135/0x160 mm/shmem.c:1933 shmem_alloc_and_add_folio+0x371/0xd40 mm/shmem.c:1975 shmem_get_folio_gfp+0x6ab/0x1900 mm/shmem.c:2564 shmem_get_folio mm/shmem.c:2670 [inline] shmem_write_begin+0x1a4/0x420 mm/shmem.c:3303 generic_perform_write+0x292/0xa40 mm/filemap.c:4325 shmem_file_write_iter+0x10e/0x140 mm/shmem.c:3478 __kernel_write_iter+0x2ac/0x920 fs/read_write.c:621 dump_emit_page fs/coredump.c:1304 [inline] dump_user_range+0x3f9/0xad0 fs/coredump.c:1378 elf_core_dump+0x2d5f/0x3d10 fs/binfmt_elf.c:2109 coredump_write fs/coredump.c:1053 [inline] do_coredump fs/coredump.c:1132 [inline] vfs_coredump+0x29a0/0x5770 fs/coredump.c:1206 get_signal+0x2162/0x2210 kernel/signal.c:3022 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop kernel/entry/common.c:98 [inline] __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:252 [inline] irqentry_exit_to_user_mode include/linux/irq-entry-common.h:323 [inline] irqentry_exit+0x410/0x7e0 kernel/entry/common.c:162 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f7249b9ce61 RSP: 002b:fffffffffffffe70 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007f7249e16090 RCX: 00007f7249b9ce59 RDX: 0000000000000000 RSI: fffffffffffffe70 RDI: 0000000000008000 RBP: 00007f7249c32d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f7249e16128 R14: 00007f7249e16090 R15: 00007ffe62b198b8 rcu: rcu_preempt kthread starved for 10496 jiffies! g36037 f0x0 RCU_GP_DOING_FQS(6) ->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:28216 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 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:476 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline] irqentry_exit+0x205/0x7e0 kernel/entry/common.c:164 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:force_qs_rnp+0x15/0x920 kernel/rcu/tree.c:2739 Code: 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 41 57 41 56 41 55 41 54 55 53 48 83 ec 60 0f b6 05 68 d2 91 0c 05 61 d2 91 0c 00 48 89 7c 24 08 88 05 55 d2 91 0c 8b 05 97 8e RSP: 0018:ffffc90000157c10 EFLAGS: 00000282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000006 RDX: 1ffffffff1c81e50 RSI: ffffffff8df22414 RDI: ffffffff81ed69e0 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff8e40f280 R13: ffffc90000157d10 R14: 0000000000000000 R15: 1ffff9200002af96 rcu_gp_fqs kernel/rcu/tree.c:2051 [inline] rcu_gp_fqs_loop+0x53c/0x900 kernel/rcu/tree.c:2117 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: 7490 Comm: kworker/u8:13 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: events_unbound toggle_allocation_gate 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:ffffc90005367870 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81fc2bcd RDX: ffff8880283d0000 RSI: ffffffff81fc2ba7 RDI: ffff8880283d0000 RBP: ffff8880b8443320 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed1017088665 R14: 0000000000000001 R15: ffff8880b853c5c0 FS: 0000000000000000(0000) GS:ffff88812446d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f506e5ea540 CR3: 000000000e596000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1057 on_each_cpu include/linux/smp.h:72 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2773 [inline] smp_text_poke_batch_finish+0x337/0xc60 arch/x86/kernel/alternative.c:2983 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x37a/0x550 kernel/jump_label.c:910 static_key_enable_cpuslocked+0x1bc/0x270 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate mm/kfence/core.c:906 [inline] toggle_allocation_gate+0xfe/0x2d0 mm/kfence/core.c:898 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314 process_scheduled_works kernel/workqueue.c:3397 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478 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