rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P2744/1:b..l P2754/1:b..l P2736/2:b..l rcu: (detected by 0, t=10502 jiffies, g=230381, q=700 ncpus=1) task:syz.1.6258 state:R running task stack:26600 pid:2736 tgid:2736 ppid:31361 task_flags:0x40004c flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x62/0x330 kernel/locking/lockdep.c:5872 Code: ea 18 12 83 f8 07 0f 87 a2 02 00 00 89 c0 48 0f a3 05 d2 7b ef 0e 0f 82 74 02 00 00 8b 35 4a ac ef 0e 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 e9 e9 18 12 0f 85 ad 02 00 00 48 83 c4 RSP: 0018:ffffc90003037428 EFLAGS: 00000206 RAX: 0000000000000046 RBX: ffffffff8e3c9520 RCX: 00000000bf3fbf97 RDX: 0000000000000000 RSI: ffffffff8daa5ccc RDI: ffffffff8bf2b780 RBP: 0000000000000002 R08: 00000000ac0d5af0 R09: 000000000ac0d5af R10: 0000000000000002 R11: ffff88802a41a9b0 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] page_ref_add_unless.constprop.0+0x36/0x390 include/linux/page_ref.h:235 folio_ref_add_unless include/linux/page_ref.h:248 [inline] folio_try_get include/linux/page_ref.h:264 [inline] find_get_entry mm/filemap.c:2076 [inline] find_lock_entries+0x1c1/0xbf0 mm/filemap.c:2166 shmem_undo_range+0x216/0x1140 mm/shmem.c:1119 shmem_truncate_range mm/shmem.c:1249 [inline] shmem_evict_inode+0x39e/0xbe0 mm/shmem.c:1379 evict+0x3c2/0xad0 fs/inode.c:837 iput_final fs/inode.c:1954 [inline] iput.part.0+0x621/0x1190 fs/inode.c:2006 iput+0x35/0x40 fs/inode.c:1969 dentry_unlink_inode+0x29c/0x480 fs/dcache.c:467 __dentry_kill+0x1d0/0x600 fs/dcache.c:670 finish_dput+0x76/0x480 fs/dcache.c:879 dput.part.0+0x451/0x570 fs/dcache.c:928 dput+0x1f/0x30 fs/dcache.c:920 __fput+0x51c/0xb70 fs/file_table.c:476 task_work_run+0x150/0x240 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x87f/0x2bd0 kernel/exit.c:971 do_group_exit+0xd3/0x2a0 kernel/exit.c:1112 __do_sys_exit_group kernel/exit.c:1123 [inline] __se_sys_exit_group kernel/exit.c:1121 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1121 x64_sys_call+0x151c/0x1740 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdb0438f7c9 RSP: 002b:00007ffd25040978 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fdb0438f7c9 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ffd250409dc R08: 0000001e25040a6f R09: 00000000000927c0 R10: 000000000003778c R11: 0000000000000246 R12: 00000000000000cb R13: 00000000000927c0 R14: 00000000001acfd0 R15: 00007ffd25040a30 task:syz.6.6261 state:R running task stack:27456 pid:2754 tgid:2745 ppid:26232 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:cpu_max_bits_warn include/linux/cpumask.h:138 [inline] RIP: 0010:cpumask_check include/linux/cpumask.h:145 [inline] RIP: 0010:cpumask_test_cpu include/linux/cpumask.h:649 [inline] RIP: 0010:cpu_online include/linux/cpumask.h:1231 [inline] RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline] RIP: 0010:lock_acquire+0x3b/0x330 kernel/locking/lockdep.c:5831 Code: 89 d5 41 54 45 89 c4 55 89 cd 53 48 89 fb 48 83 ec 38 65 48 8b 05 2d ea 18 12 48 89 44 24 30 31 c0 66 90 65 8b 05 49 ea 18 12 <83> f8 07 0f 87 a2 02 00 00 89 c0 48 0f a3 05 d2 7b ef 0e 0f 82 74 RSP: 0018:ffffc9000c267130 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffffff8e3c9520 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e3c9520 RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000012710 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 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+0xd1/0x20b0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x89/0x90 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:5263 [inline] kmem_cache_alloc_node_noprof+0x298/0x800 mm/slub.c:5315 __alloc_skb+0x156/0x410 net/core/skbuff.c:679 alloc_skb include/linux/skbuff.h:1383 [inline] alloc_skb_with_frags+0xe0/0x860 net/core/skbuff.c:6714 sock_alloc_send_pskb+0x7f9/0x980 net/core/sock.c:2995 unix_dgram_sendmsg+0x3bc/0x1830 net/unix/af_unix.c:2130 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2646 __sys_sendmmsg+0x200/0x420 net/socket.c:2735 __do_sys_sendmmsg net/socket.c:2762 [inline] __se_sys_sendmmsg net/socket.c:2759 [inline] __x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2759 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5194f8f7c9 RSP: 002b:00007f5195d5a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f51951e6180 RCX: 00007f5194f8f7c9 RDX: 00000000000009a6 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 00007f5195013f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000006 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f51951e6218 R14: 00007f51951e6180 R15: 00007ffffd2ce048 task:syz.5.6260 state:R running task stack:26832 pid:2744 tgid:2743 ppid:25269 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__kasan_check_byte+0xe/0x50 mm/kasan/common.c:573 Code: e9 d7 34 00 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 1f 40 d6 41 54 49 89 f4 55 48 89 fd 53 8d 25 00 00 89 c3 84 c0 74 0b 89 d8 5b 5d 41 5c c3 cc cc cc cc RSP: 0018:ffffc900035ff1b8 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffffffff8e3c9520 RCX: 0000000000000002 RDX: 0000000000000000 RSI: ffffffff816c7711 RDI: ffffffff8e3c9520 RBP: ffffffff8e3c9520 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000084587 R12: ffffffff816c7711 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 kasan_check_byte include/linux/kasan.h:402 [inline] lock_acquire kernel/locking/lockdep.c:5842 [inline] lock_acquire+0xfc/0x330 kernel/locking/lockdep.c:5825 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+0xd1/0x20b0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6670 [inline] kmem_cache_free+0x2d8/0x770 mm/slub.c:6781 kfree_skbmem+0x1a4/0x1f0 net/core/skbuff.c:1130 __kfree_skb net/core/skbuff.c:1197 [inline] consume_skb net/core/skbuff.c:1428 [inline] consume_skb+0xcc/0x100 net/core/skbuff.c:1422 netlink_broadcast_filtered+0x3ee/0xf90 net/netlink/af_netlink.c:1535 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline] nlmsg_multicast include/net/netlink.h:1184 [inline] nlmsg_notify+0x9e/0x220 net/netlink/af_netlink.c:2593 inet6_ifmcaddr_notify+0x128/0x1d0 net/ipv6/mcast.c:923 __ipv6_dev_mc_inc+0x70a/0xbc0 net/ipv6/mcast.c:973 ipv6_add_dev+0xbb7/0x15f0 net/ipv6/addrconf.c:472 addrconf_notify+0x53e/0x19f0 net/ipv6/addrconf.c:3650 notifier_call_chain+0xbc/0x3e0 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x110 net/core/dev.c:2243 call_netdevice_notifiers_extack net/core/dev.c:2281 [inline] call_netdevice_notifiers net/core/dev.c:2295 [inline] register_netdevice+0x17a7/0x21e0 net/core/dev.c:11444 register_netdev+0x34/0x50 net/core/dev.c:11522 sit_init_net+0x286/0x630 net/ipv6/sit.c:1859 ops_init+0x1e2/0x5f0 net/core/net_namespace.c:137 setup_net+0x11d/0x3a0 net/core/net_namespace.c:446 copy_net_ns+0x351/0x7c0 net/core/net_namespace.c:581 create_new_namespaces+0x3ea/0xab0 kernel/nsproxy.c:130 unshare_nsproxy_namespaces+0xc0/0x1f0 kernel/nsproxy.c:226 ksys_unshare+0x45b/0xa40 kernel/fork.c:3171 __do_sys_unshare kernel/fork.c:3242 [inline] __se_sys_unshare kernel/fork.c:3240 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:3240 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f945a98f7c9 RSP: 002b:00007f945b7e0038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 00007f945abe5fa0 RCX: 00007f945a98f7c9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000080 RBP: 00007f945aa13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f945abe6038 R14: 00007f945abe5fa0 R15: 00007ffe60de2248 rcu: rcu_preempt kthread starved for 10500 jiffies! g230381 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:28328 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6960 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 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: 0 UID: 0 PID: 31222 Comm: kworker/u8:54 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: events_unbound cfg80211_wiphy_work RIP: 0010:lock_release+0x183/0x2d0 kernel/locking/lockdep.c:5893 Code: 0f c1 05 a8 36 19 12 83 f8 01 0f 85 03 01 00 00 9c 58 f6 c4 02 0f 85 ee 00 00 00 41 f7 c5 00 02 00 00 74 01 fb 48 8b 44 24 10 <65> 48 2b 05 3d ef 18 12 0f 85 32 01 00 00 48 83 c4 18 5b 41 5c 41 RSP: 0018:ffffc90000006f48 EFLAGS: 00000206 RAX: e4865a2e925c5600 RBX: ffffffff8e3c9520 RCX: ffffc90000006f54 RDX: 0000000000000004 RSI: ffffffff8daa5ccc RDI: ffffffff8bf2b780 RBP: 0000000000000001 R08: 0000000000000001 R09: 000000000ac0d5af R10: 0000000000000002 R11: 000000000000867b R12: ffffffff816c7a34 R13: 0000000000000206 R14: ffff888048bc3d00 R15: 0000000000000005 FS: 0000000000000000(0000) GS:ffff8881248f9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8162698482 CR3: 000000000e184000 CR4: 00000000003526f0 Call Trace: rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:897 [inline] class_rcu_destructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0x3f9/0x20b0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6670 [inline] kmem_cache_free+0x2d8/0x770 mm/slub.c:6781 kfree_skbmem+0x1a4/0x1f0 net/core/skbuff.c:1130 __kfree_skb net/core/skbuff.c:1197 [inline] consume_skb net/core/skbuff.c:1428 [inline] consume_skb+0xcc/0x100 net/core/skbuff.c:1422 netlink_broadcast_filtered+0x3ee/0xf90 net/netlink/af_netlink.c:1535 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline] nlmsg_multicast include/net/netlink.h:1184 [inline] nlmsg_notify+0x9e/0x220 net/netlink/af_netlink.c:2593 fdb_notify+0xfd/0x1a0 net/bridge/br_fdb.c:199 br_fdb_update+0x31e/0x7c0 net/bridge/br_fdb.c:1040 br_handle_frame_finish+0xdf1/0x1f00 net/bridge/br_input.c:144 nf_hook_bridge_pre net/bridge/br_input.c:313 [inline] br_handle_frame+0xdde/0x14e0 net/bridge/br_input.c:442 __netif_receive_skb_core.constprop.0+0x6b3/0x35b0 net/core/dev.c:6039 __netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:6150 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6265 process_backlog+0x4ab/0x1650 net/core/dev.c:6617 __napi_poll.constprop.0+0xb3/0x540 net/core/dev.c:7681 napi_poll net/core/dev.c:7744 [inline] net_rx_action+0x9f9/0xfa0 net/core/dev.c:7896 handle_softirqs+0x219/0x950 kernel/softirq.c:622 do_softirq kernel/softirq.c:523 [inline] do_softirq+0xb2/0xf0 kernel/softirq.c:510 __local_bh_enable_ip+0x100/0x120 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:396 [inline] cfg80211_inform_single_bss_data+0x9ad/0x1d30 net/wireless/scan.c:2389 cfg80211_inform_bss_data+0x22b/0x3be0 net/wireless/scan.c:3228 cfg80211_inform_bss_frame_data+0x26f/0x720 net/wireless/scan.c:3319 ieee80211_bss_info_update+0x310/0xab0 net/mac80211/scan.c:230 ieee80211_rx_bss_info net/mac80211/ibss.c:1094 [inline] ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1575 [inline] ieee80211_ibss_rx_queued_mgmt+0x1927/0x2fc0 net/mac80211/ibss.c:1602 ieee80211_iface_process_skb net/mac80211/iface.c:1736 [inline] ieee80211_iface_work+0xe28/0x1350 net/mac80211/iface.c:1790 cfg80211_wiphy_work+0x3fb/0x560 net/wireless/core.c:438 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246