rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6535/1:b..l P2/1:b..l P6550/1:b..l rcu: (detected by 0, t=10503 jiffies, g=16433, q=951010 ncpus=2) task:syz.2.130 state:R running task stack:26152 pid:6550 tgid:6548 ppid:5855 task_flags:0x40054c flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6947 preempt_schedule+0xe4/0xf0 kernel/sched/core.c:6971 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] zap_pte_range mm/memory.c:1761 [inline] zap_pmd_range mm/memory.c:1823 [inline] zap_pud_range mm/memory.c:1852 [inline] zap_p4d_range mm/memory.c:1873 [inline] unmap_page_range+0x39c5/0x44d0 mm/memory.c:1894 unmap_vmas+0x3ce/0x5f0 mm/memory.c:1984 exit_mmap+0x2bc/0xde0 mm/mmap.c:1284 __mmput+0x115/0x420 kernel/fork.c:1379 exit_mm+0x221/0x310 kernel/exit.c:589 do_exit+0x994/0x27f0 kernel/exit.c:940 do_group_exit+0x207/0x2c0 kernel/exit.c:1102 get_signal+0x1696/0x1730 kernel/signal.c:3034 arch_do_signal_or_restart+0x98/0x840 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa316f8d169 RSP: 002b:00007fa317e460e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 0000000000000001 RBX: 00007fa3171a5fa8 RCX: 00007fa316f8d169 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007fa3171a5fac RBP: 00007fa3171a5fa0 R08: 7fffffffffffffff R09: 0000000000000000 R10: 0000000000000004 R11: 0000000000000246 R12: 00007fa3171a5fac R13: 0000000000000000 R14: 00007fa3172cf940 R15: 00007fa3172cfa28 task:kthreadd state:R running task stack:25432 pid:2 tgid:2 ppid:0 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 preempt_schedule_irq+0xfe/0x1c0 kernel/sched/core.c:7090 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:118 [inline] RIP: 0010:lock_acquire+0x90/0x2f0 kernel/locking/lockdep.c:5842 Code: aa 0e 01 0f 84 9b 01 00 00 83 3d 6a 0f c1 0e 00 0f 84 e6 00 00 00 48 8b 74 24 70 48 89 df e8 57 61 8e 00 83 3d 50 0f c1 0e 00 <0f> 84 ef 00 00 00 65 8b 05 33 bd c9 11 85 c0 0f 85 e0 00 00 00 65 RSP: 0018:ffffc90000077168 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffffffff8ed3dfe0 RCX: 0000000000000002 RDX: 0000000000000000 RSI: ffffffff816dfbe5 RDI: 1ffffffff1da7bfc RBP: ffffffff93687020 R08: 0000000000000000 R09: 0000000000000000 R10: ffffc90000077310 R11: ffffffff81aee9b0 R12: 0000000000000000 R13: 0000000000000002 R14: ffffffff818e6214 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+0xd5/0x23b0 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11e/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x11a/0x1d0 kernel/stacktrace.c:122 save_stack+0xfc/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x76/0x1e0 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_frozen_pages+0xde8/0x10a0 mm/page_alloc.c:2680 discard_slab mm/slub.c:2720 [inline] __put_partials+0x160/0x1c0 mm/slub.c:3189 put_cpu_partial+0x17e/0x250 mm/slub.c:3264 __slab_free+0x294/0x390 mm/slub.c:4516 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4151 [inline] slab_alloc_node mm/slub.c:4200 [inline] __do_kmalloc_node mm/slub.c:4330 [inline] __kmalloc_noprof+0x238/0x4d0 mm/slub.c:4343 kmalloc_noprof include/linux/slab.h:909 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] lsm_blob_alloc security/security.c:684 [inline] lsm_cred_alloc security/security.c:701 [inline] security_prepare_creds+0x53/0x360 security/security.c:3241 prepare_creds+0x4b4/0x6f0 kernel/cred.c:242 copy_creds+0x109/0x9c0 kernel/cred.c:312 copy_process+0x9ec/0x3d10 kernel/fork.c:2293 kernel_clone+0x242/0x930 kernel/fork.c:2844 kernel_thread+0x1c2/0x250 kernel/fork.c:2906 create_kthread kernel/kthread.c:487 [inline] kthreadd+0x621/0x850 kernel/kthread.c:847 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 task:syz.5.126 state:R running task stack:22216 pid:6535 tgid:6534 ppid:6153 task_flags:0x480140 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 preempt_schedule_irq+0xfe/0x1c0 kernel/sched/core.c:7090 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x167/0x2f0 arch/x86/include/asm/irqflags.h:-1 Code: c7 44 24 10 00 00 00 00 9c 8f 44 24 10 f7 44 24 10 00 02 00 00 0f 85 fd 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 65 48 8b 45 00 <48> 3b 44 24 38 0f 85 72 01 00 00 48 83 c4 40 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc900034b6288 EFLAGS: 00000206 RAX: c28730d7f1d19600 RBX: ffffffff8ed3dfe0 RCX: c28730d7f1d19600 RDX: 0000000000000000 RSI: ffffffff8e4fc666 RDI: ffffffff8ca1b140 RBP: ffffffff93687020 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000002 R14: 0000000000000246 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+0xd5/0x23b0 arch/x86/kernel/unwind_orc.c:479 __unwind_start+0x59a/0x740 arch/x86/kernel/unwind_orc.c:758 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe7/0x150 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x11a/0x1d0 kernel/stacktrace.c:122 save_stack+0xfc/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x76/0x1e0 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_frozen_pages+0xde8/0x10a0 mm/page_alloc.c:2680 discard_slab mm/slub.c:2720 [inline] __put_partials+0x160/0x1c0 mm/slub.c:3189 put_cpu_partial+0x17e/0x250 mm/slub.c:3264 __slab_free+0x294/0x390 mm/slub.c:4516 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4151 [inline] slab_alloc_node mm/slub.c:4200 [inline] __do_kmalloc_node mm/slub.c:4330 [inline] __kmalloc_noprof+0x238/0x4d0 mm/slub.c:4343 kmalloc_noprof include/linux/slab.h:909 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] kobject_get_path+0xc3/0x2c0 lib/kobject.c:161 kobject_uevent_env+0x2a5/0x8e0 lib/kobject_uevent.c:545 device_del+0x7dd/0x9b0 drivers/base/core.c:3873 unregister_netdevice_many_notify+0x1f37/0x2510 net/core/dev.c:12009 unregister_netdevice_many net/core/dev.c:12037 [inline] unregister_netdevice_queue+0x383/0x400 net/core/dev.c:11889 br_dev_newlink+0x115/0x140 net/bridge/br_netlink.c:1577 rtnl_newlink_create+0x39b/0xcb0 net/core/rtnetlink.c:3833 __rtnl_newlink net/core/rtnetlink.c:3950 [inline] rtnl_newlink+0x18b0/0x1fe0 net/core/rtnetlink.c:4065 rtnetlink_rcv_msg+0x80f/0xd70 net/core/rtnetlink.c:6955 netlink_rcv_skb+0x208/0x480 net/netlink/af_netlink.c:2534 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x7f8/0x9a0 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x8c3/0xcd0 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:727 ____sys_sendmsg+0x523/0x860 net/socket.c:2566 ___sys_sendmsg net/socket.c:2620 [inline] __sys_sendmsg+0x271/0x360 net/socket.c:2652 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fad4178d169 RSP: 002b:00007fad4267a038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fad419a5fa0 RCX: 00007fad4178d169 RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000003 RBP: 00007fad4180e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fad419a5fa0 R15: 00007fad41acfa28 rcu: rcu_preempt kthread starved for 9899 jiffies! g16433 f0x2 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:26376 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x163/0x360 kernel/sched/core.c:6860 schedule_timeout+0x15b/0x2b0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2e1/0x1340 kernel/rcu/tree.c:2046 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2248 kthread+0x7b7/0x940 kernel/kthread.c:464 ret_from_fork+0x4b/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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.14.0-syzkaller-12966-ga2cc6ff5ec8f #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:__lock_acquire+0x6a1/0xd80 kernel/locking/lockdep.c:5205 Code: 00 0f 84 c2 00 00 00 48 8b 3c 24 4c 89 f6 ba 08 00 00 00 e8 a1 2a 00 00 45 31 ed 85 c0 0f 84 7d 04 00 00 83 3d ef 9d d4 18 00 <75> 13 48 63 44 24 10 48 0f a3 05 b0 0e d1 12 0f 83 90 05 00 00 31 RSP: 0018:ffffc90000a07608 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000003 RCX: 0000000000000009 RDX: 0000000000000008 RSI: ffff88801d6f6568 RDI: ffff88801d6f5a00 RBP: 00000000ffffffff R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88801d6f6588 R13: 0000000000000000 R14: ffff88801d6f6568 R15: 0000000000000003 FS: 0000000000000000(0000) GS:ffff888125099000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f4e95c00218 CR3: 0000000064ae0000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 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+0xd5/0x23b0 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11e/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x11a/0x1d0 kernel/stacktrace.c:122 ref_tracker_alloc+0x19f/0x4c0 lib/ref_tracker.c:209 __netdev_tracker_alloc include/linux/netdevice.h:4331 [inline] netdev_hold include/linux/netdevice.h:4360 [inline] dst_init+0xee/0x490 net/core/dst.c:52 dst_alloc+0x14f/0x190 net/core/dst.c:93 rt_dst_alloc net/ipv4/route.c:1638 [inline] __mkroute_output net/ipv4/route.c:2632 [inline] ip_route_output_key_hash_rcu+0x1378/0x2290 net/ipv4/route.c:2854 ip_route_output_key_hash+0x195/0x2b0 net/ipv4/route.c:2683 __ip_route_output_key include/net/route.h:169 [inline] ip_route_output_flow+0x29/0x140 net/ipv4/route.c:2911 ip_route_output_key include/net/route.h:179 [inline] ip_route_me_harder+0x852/0x13e0 net/ipv4/netfilter.c:53 synproxy_send_tcp+0x356/0x6c0 net/netfilter/nf_synproxy_core.c:431 synproxy_send_client_synack+0x8ea/0xf70 net/netfilter/nf_synproxy_core.c:484 nft_synproxy_eval_v4+0x3cc/0x610 net/netfilter/nft_synproxy.c:59 nft_synproxy_do_eval+0x36a/0xa90 net/netfilter/nft_synproxy.c:141 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x4b2/0x1db0 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0x41f/0x6b0 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xc8/0x220 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:269 [inline] NF_HOOK+0x29b/0x450 include/linux/netfilter.h:312 NF_HOOK+0x3a0/0x450 include/linux/netfilter.h:314 __netif_receive_skb_one_core net/core/dev.c:5891 [inline] __netif_receive_skb+0x2c9/0x670 net/core/dev.c:6004 process_backlog+0x664/0x15c0 net/core/dev.c:6356 __napi_poll+0xcb/0x480 net/core/dev.c:7328 napi_poll net/core/dev.c:7392 [inline] net_rx_action+0x89d/0x1240 net/core/dev.c:7514 handle_softirqs+0x2d6/0x9b0 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] invoke_softirq kernel/softirq.c:453 [inline] __irq_exit_rcu+0xfb/0x220 kernel/softirq.c:680 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81 Code: 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 33 01 18 00 f3 0f 1e fa fb f4 cc cc cc cc 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197dc0 EFLAGS: 000002c2 RAX: 5f310d0ddcc6e100 RBX: ffffffff8197afbe RCX: ffffffff8c30393c RDX: 0000000000000001 RSI: ffffffff8e69b738 RDI: ffffffff8ca1b140 RBP: ffffc90000197f20 R08: ffff8880b8732b5b R09: 1ffff110170e656b R10: dffffc0000000000 R11: ffffed10170e656c R12: 1ffff92000032fd2 R13: 1ffff11003adeb40 R14: 0000000000000001 R15: dffffc0000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:748 default_idle_call+0x74/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:185 [inline] do_idle+0x22e/0x5d0 kernel/sched/idle.c:325 cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:423 start_secondary+0xfe/0x100 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x147