syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P8656/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=36325, q=645 ncpus=2)
task:syz.0.702       state:R  running task     stack:25544 pid:8656  tgid:8648  ppid:5848   task_flags:0x400040 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7108
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:307
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:unwind_next_frame+0x39e/0x2390 arch/x86/kernel/unwind_orc.c:505
Code: 84 c0 0f 85 6d 19 00 00 4c 89 e8 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 80 19 00 00 41 0f b6 44 24 01 83 e0 07 0f 84 75 15 00 00 <83> f8 01 4c 8b 7c 24 48 48 bd 00 00 00 00 00 fc ff df 4c 8b 64 24
RSP: 0018:ffffc900046f72b8 EFLAGS: 00000202
RAX: 0000000000000002 RBX: ffffffff8fbe2714 RCX: ffffffff8fbe2718
RDX: ffffffff903e3c5c RSI: ffffffff903e3c5c RDI: ffffffff8be28ce0
RBP: dffffc0000000000 R08: 0000000000000001 R09: ffffffff81728af5
R10: ffffc900046f73d8 R11: ffffffff81ace6a0 R12: ffffffff903e3c60
R13: ffffffff903e3c61 R14: ffffc900046f7388 R15: ffffffff8fbe2714
 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:156
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:308
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 __free_frozen_pages+0xc71/0xe70 mm/page_alloc.c:2706
 discard_slab mm/slub.c:2717 [inline]
 __put_partials+0x161/0x1c0 mm/slub.c:3186
 put_cpu_partial+0x17c/0x250 mm/slub.c:3261
 __slab_free+0x2f7/0x400 mm/slub.c:4513
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4148 [inline]
 slab_alloc_node mm/slub.c:4197 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kmalloc_noprof+0x224/0x4f0 mm/slub.c:4340
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kmalloc_array_noprof include/linux/slab.h:948 [inline]
 snd_pcm_plugin_build+0x267/0x500 sound/core/oss/pcm_plugin.c:181
 snd_pcm_plugin_build_mulaw+0x227/0x750 sound/core/oss/mulaw.c:335
 snd_pcm_plug_format_plugins+0xad6/0x10f0 sound/core/oss/pcm_plugin.c:498
 snd_pcm_oss_change_params_locked+0x2302/0x3e40 sound/core/oss/pcm_oss.c:975
 snd_pcm_oss_change_params sound/core/oss/pcm_oss.c:1104 [inline]
 snd_pcm_oss_get_active_substream+0x20b/0x280 sound/core/oss/pcm_oss.c:1121
 snd_pcm_oss_get_formats+0x34/0x420 sound/core/oss/pcm_oss.c:1842
 snd_pcm_oss_set_format+0x41/0x500 sound/core/oss/pcm_oss.c:1882
 snd_pcm_oss_ioctl+0xbe9/0xdd0 sound/core/oss/pcm_oss.c:2647
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff30098e929
RSP: 002b:00007ff30184c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ff300bb6240 RCX: 00007ff30098e929
RDX: 00002000000000c0 RSI: 00000000c0045005 RDI: 0000000000000009
RBP: 00007ff300a10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007ff300bb6240 R15: 00007ff300cdfa28
 </TASK>
rcu: rcu_preempt kthread starved for 1376 jiffies! g36325 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:27128 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6878
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 5876 Comm: kworker/R-wg-cr Not tainted 6.16.0-rc3-syzkaller-00306-gaaf724ed6926 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: wg-crypt-wg0 wg_packet_decrypt_worker
RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5875
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 3b dd fe 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc90000a07b18 EFLAGS: 00000206
RAX: 6974dfd692272900 RBX: 0000000000000000 RCX: 6974dfd692272900
RDX: 0000000000000000 RSI: ffffffff8db6ee1a RDI: ffffffff8be28d40
RBP: ffffffff81728af5 R08: 0000000000000000 R09: ffffffff81728af5
R10: ffffc90000a07cd8 R11: ffffffff81ace6a0 R12: 0000000000000002
R13: ffffffff8e13ee60 R14: 0000000000000000 R15: 0000000000000246
FS:  0000000000000000(0000) GS:ffff888125d50000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000404030 CR3: 000000007ecd0000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 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+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
 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:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4148 [inline]
 slab_alloc_node mm/slub.c:4197 [inline]
 kmem_cache_alloc_node_noprof+0x1bb/0x3c0 mm/slub.c:4249
 kmalloc_reserve+0xbd/0x290 net/core/skbuff.c:579
 __alloc_skb+0x142/0x2d0 net/core/skbuff.c:670
 alloc_skb include/linux/skbuff.h:1336 [inline]
 nlmsg_new include/net/netlink.h:1041 [inline]
 fdb_notify+0xa6/0x160 net/bridge/br_fdb.c:188
 br_fdb_update+0x4c8/0x690 net/bridge/br_fdb.c:934
 br_handle_frame_finish+0x573/0x19b0 net/bridge/br_input.c:144
 br_nf_hook_thresh+0x3c3/0x4a0 net/bridge/br_netfilter_hooks.c:-1
 br_nf_pre_routing_finish_ipv6+0x948/0xd00 net/bridge/br_netfilter_ipv6.c:-1
 NF_HOOK include/linux/netfilter.h:317 [inline]
 br_nf_pre_routing_ipv6+0x37e/0x6b0 net/bridge/br_netfilter_ipv6.c:184
 nf_hook_entry_hookfn include/linux/netfilter.h:157 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:283 [inline]
 br_handle_frame+0x982/0x14c0 net/bridge/br_input.c:434
 __netif_receive_skb_core+0x10e1/0x4180 net/core/dev.c:5863
 __netif_receive_skb_one_core net/core/dev.c:5975 [inline]
 __netif_receive_skb+0x72/0x380 net/core/dev.c:6090
 process_backlog+0x60e/0x14f0 net/core/dev.c:6442
 __napi_poll+0xc4/0x480 net/core/dev.c:7414
 napi_poll net/core/dev.c:7478 [inline]
 net_rx_action+0x707/0xe30 net/core/dev.c:7605
 handle_softirqs+0x286/0x870 kernel/softirq.c:579
 do_softirq+0xec/0x180 kernel/softirq.c:480
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x17d/0x1c0 kernel/softirq.c:407
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 ptr_ring_consume_bh include/linux/ptr_ring.h:367 [inline]
 wg_packet_decrypt_worker+0x299/0xd10 drivers/net/wireguard/receive.c:499
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 rescuer_thread+0x53c/0xdd0 kernel/workqueue.c:3498
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>