rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5198/1:b..l P5966/1:b..l P5969/1:b..l rcu: (detected by 1, t=10502 jiffies, g=19113, q=947 ncpus=2) task:syz-executor state:R running task stack:21128 pid:5969 tgid:5969 ppid:5968 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193 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:kasan_check_range+0x1da/0x2c0 mm/kasan/generic.c:200 Code: 07 4d 85 e4 49 0f 49 dc 48 83 e3 f8 49 29 dc 74 12 41 80 3b 00 0f 85 b8 00 00 00 49 ff c3 49 ff cc 75 ee 5b 41 5c 41 5d 41 5e <41> 5f 5d c3 cc cc cc cc cc 45 84 ff 75 63 41 f7 c7 00 ff 00 00 75 RSP: 0018:ffffc90003d1f220 EFLAGS: 00000256 RAX: ffffc90003d1f401 RBX: 0000000000000010 RCX: ffffffff81743d8e RDX: 0000000000000001 RSI: 0000000000000010 RDI: ffffc90003d1f378 RBP: 0000000000000000 R08: ffffc90003d1f387 R09: 1ffff920007a3e70 R10: dffffc0000000000 R11: fffff520007a3e71 R12: ffffc90003d1f378 R13: 1ffff920007a3e67 R14: ffffc90003d1f378 R15: 1ffff920007a3e6f __asan_memset+0x22/0x50 mm/kasan/shadow.c:84 unwind_next_frame+0xeae/0x23d0 arch/x86/kernel/unwind_orc.c:607 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5267 [inline] kmem_cache_alloc_noprof+0x37d/0x710 mm/slub.c:5274 anon_vma_chain_alloc mm/rmap.c:141 [inline] anon_vma_clone+0xb8/0x4f0 mm/rmap.c:287 anon_vma_fork+0x79/0x500 mm/rmap.c:350 dup_mmap+0x954/0x1b80 mm/mmap.c:1790 dup_mm kernel/fork.c:1533 [inline] copy_mm+0x14f/0x770 kernel/fork.c:1585 copy_process+0x165d/0x3950 kernel/fork.c:2225 kernel_clone+0x21e/0x820 kernel/fork.c:2655 __do_sys_clone kernel/fork.c:2796 [inline] __se_sys_clone kernel/fork.c:2780 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2780 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: 0033:0x7f8abf385e93 RSP: 002b:00007fff56a13d78 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f8abf385e93 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 00005555793c77d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 000000000002c152 R15: 00007fff56a13f10 task:syz-executor state:R running task stack:19408 pid:5966 tgid:5966 ppid:5958 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x5/0x340 kernel/locking/lockdep.c:5828 Code: a9 00 ff ff 00 0f 95 c0 e9 c8 2e c2 09 cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 <41> 57 41 56 41 55 41 54 53 48 83 ec 60 4d 89 ce 45 89 c7 41 89 cc RSP: 0000:ffffc90003d0f120 EFLAGS: 00000246 RAX: 0000000000000001 RBX: ffffffff821aa291 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e13f2e0 RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000000 R10: ffffc90003d0f258 R11: ffffffff81ad9d50 R12: 1ffff920007a1e41 R13: ffffc90003d0f240 R14: ffffc90003d0f208 R15: ffffffff81742f85 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495 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:165 __set_page_owner+0x8d/0x4c0 mm/page_owner.c:341 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x234/0x290 mm/page_alloc.c:1857 prep_new_page mm/page_alloc.c:1865 [inline] get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486 folio_alloc_mpol_noprof mm/mempolicy.c:2505 [inline] vma_alloc_folio_noprof+0xe4/0x200 mm/mempolicy.c:2540 folio_prealloc+0x30/0x180 mm/memory.c:-1 wp_page_copy mm/memory.c:3719 [inline] do_wp_page+0x1231/0x5750 mm/memory.c:4180 handle_pte_fault mm/memory.c:6289 [inline] __handle_mm_fault mm/memory.c:6411 [inline] handle_mm_fault+0x14c5/0x32b0 mm/memory.c:6580 do_user_addr_fault+0xa7c/0x1380 arch/x86/mm/fault.c:1336 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7fc2efb85d16 RSP: 002b:00007fff88383fe0 EFLAGS: 00010202 RAX: 0000000000000340 RBX: 0000000000000000 RCX: 00007fc2efb85e93 RDX: 0000000000000340 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 0000555577aaa7d0 R11: 0000000000000246 R12: 0000000000000340 R13: ffffffffffffffa8 R14: 0000000000000006 R15: 00007fff88384170 task:udevd state:R running task stack:25072 pid:5198 tgid:5198 ppid:1 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193 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:lock_acquire+0x16c/0x340 kernel/locking/lockdep.c:5872 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 44 41 01 11 <48> 3b 44 24 58 0f 85 e5 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc90003207298 EFLAGS: 00000206 RAX: 4b36deb6dd6b4f00 RBX: 0000000000000000 RCX: 4b36deb6dd6b4f00 RDX: 00000000d96c2560 RSI: ffffffff8db7ed49 RDI: ffffffff8be07960 RBP: ffffffff81742f85 R08: ffffffff81742f85 R09: ffffffff8e13f2e0 R10: ffffc900032074b8 R11: fffff52000640e99 R12: 0000000000000002 R13: ffffffff8e13f2e0 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495 __unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:773 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe4/0x150 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5267 [inline] kmem_cache_alloc_noprof+0x37d/0x710 mm/slub.c:5274 skb_clone+0x212/0x3a0 net/core/skbuff.c:2087 do_one_broadcast net/netlink/af_netlink.c:1455 [inline] netlink_broadcast_filtered+0x6ae/0x1000 net/netlink/af_netlink.c:1533 netlink_broadcast+0x37/0x50 net/netlink/af_netlink.c:1557 uevent_net_broadcast_untagged lib/kobject_uevent.c:331 [inline] kobject_uevent_net_broadcast+0x378/0x560 lib/kobject_uevent.c:410 kobject_uevent_env+0x55c/0x9f0 lib/kobject_uevent.c:608 kobject_synth_uevent+0x527/0xb00 lib/kobject_uevent.c:207 uevent_store+0x26/0x70 drivers/base/core.c:2773 kernfs_fop_write_iter+0x3af/0x540 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5c9/0xb30 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 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: 0033:0x7fe8846a7407 RSP: 002b:00007ffd017482f0 EFLAGS: 00000202 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fe884d8f880 RCX: 00007fe8846a7407 RDX: 0000000000000007 RSI: 00005628a897c550 RDI: 000000000000000c RBP: 00005628a897c550 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000007 R13: 00005628a89788a0 R14: 00007fe8847efea0 R15: 00007ffd01748650 rcu: rcu_preempt kthread starved for 10530 jiffies! g19113 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:27728 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 __schedule_loop kernel/sched/core.c:6948 [inline] schedule+0x165/0x360 kernel/sched/core.c:6963 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: CPU: 1 UID: 0 PID: 10168 Comm: syz.2.2046 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:memset_orig+0x25/0xb0 arch/x86/lib/memset_64.S:64 Code: 90 90 90 90 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 01 01 48 0f af c1 41 89 f9 41 83 e1 07 75 74 48 89 d1 48 c1 e9 06 <74> 39 66 0f 1f 84 00 00 00 00 00 48 ff c9 48 89 07 48 89 47 08 48 RSP: 0018:ffffc90004dcf8f8 EFLAGS: 00000247 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000020 RSI: 0000000000000000 RDI: ffffc90004dcf9b0 RBP: ffffc90004dcfad0 R08: ffffc90004dcf9cf R09: 0000000000000000 R10: ffffc90004dcf9b0 R11: fffff520009b9f3a R12: ffffc90004dcf9f0 R13: dffffc0000000000 R14: 00007fce0bd86d00 R15: 00007fce0bd86d00 FS: 00007fce0bd876c0(0000) GS:ffff888125d25000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000058 CR3: 000000007625e000 CR4: 00000000003526f0 Call Trace: save_xstate_epilog arch/x86/kernel/fpu/signal.c:116 [inline] copy_fpstate_to_sigframe+0x948/0xcc0 arch/x86/kernel/fpu/signal.c:232 get_sigframe+0x58d/0x7d0 arch/x86/kernel/signal.c:163 x64_setup_rt_frame+0x15b/0xd40 arch/x86/kernel/signal_64.c:175 setup_rt_frame arch/x86/kernel/signal.c:250 [inline] handle_signal arch/x86/kernel/signal.c:294 [inline] arch_do_signal_or_restart+0x3d1/0x7a0 arch/x86/kernel/signal.c:339 __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+0x2d0/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fce0af8f747 Code: ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 <0f> 05 48 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 RSP: 002b:00007fce0bd870e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 00000000000000ca RBX: 00007fce0b1e5fa8 RCX: 00007fce0af8f749 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fce0b1e5fa8 RBP: 00007fce0b1e5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fce0b1e6038 R14: 00007ffdc53f4410 R15: 00007ffdc53f44f8