rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (2 ticks this GP) idle=125c/1/0x4000000000000000 softirq=16094/16094 fqs=5
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P913/1:b..l
rcu: (detected by 0, t=10504 jiffies, g=12945, q=1432 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5596 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:trace_hrtimer_start+0x77/0x220 include/trace/events/timer.h:223
Code: d0 73 22 91 e8 4a 11 85 00 48 0f a3 1d 62 98 2c 0f 0f 92 c3 31 ff 89 de e8 d6 7e 14 00 84 db 0f 85 2f 01 00 00 e8 b9 84 14 00 <5b> 5d 41 5c 41 5d 41 5e e9 cc 75 c8 09 e8 a7 84 14 00 65 8b 1d 94
RSP: 0018:ffffc90000a07a90 EFLAGS: 00000006
RAX: 0000000000010102 RBX: 0000000000000001 RCX: ffffffff81f5dcc6
RDX: ffff88807ecda540 RSI: ffffffff81f5db87 RDI: ffff88807ecda540
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff88801e3b9300
R13: 0000000000000000 R14: 0000000000000001 R15: ffff8880b8528590
FS: 0000555585a6b540(0000) GS:ffff888123edc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8fc01c0000 CR3: 00000000779df000 CR4: 00000000003526f0
Call Trace:
debug_activate kernel/time/hrtimer.c:529 [inline]
enqueue_hrtimer+0x84/0x2f0 kernel/time/hrtimer.c:1109
__run_hrtimer kernel/time/hrtimer.c:2048 [inline]
__hrtimer_run_queues+0x6ed/0x9c0 kernel/time/hrtimer.c:2096
hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2215
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
__sysvec_apic_timer_interrupt+0x109/0x470 arch/x86/kernel/apic/apic.c:1068
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0x51/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:__orc_find+0x3d/0xf0 arch/x86/kernel/unwind_orc.c:105
Code: 53 48 83 ec 08 85 d2 0f 84 99 00 00 00 49 89 fe 48 89 f0 49 39 fc 72 7b 48 b9 00 00 00 00 00 fc ff df 49 89 ff 48 89 fd eb 0c <48> 8d 6b 04 49 89 df 49 39 ec 72 4e 4c 89 e2 48 29 ea 48 89 d6 48
RSP: 0018:ffffc90000a07d10 EFLAGS: 00000206
RAX: ffffffff9258cc56 RBX: ffffffff919e48a8 RCX: dffffc0000000000
RDX: ffffffff8985ffe2 RSI: 0000000000000000 RDI: ffffffff919e48a8
RBP: ffffffff919e48a8 R08: ffffffff9258cc5c R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000088600 R12: ffffffff919e48a8
R13: ffffffff8986000f R14: ffffffff919e48a8 R15: ffffffff919e48a8
orc_find arch/x86/kernel/unwind_orc.c:238 [inline]
unwind_next_frame+0x2ec/0x2090 arch/x86/kernel/unwind_orc.c:510
arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
kasan_save_free_info+0x3b/0x70 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:2677 [inline]
slab_free mm/slub.c:6377 [inline]
kfree+0x22b/0x6c0 mm/slub.c:6692
skb_kfree_head net/core/skbuff.c:1077 [inline]
skb_free_head+0xb9/0x160 net/core/skbuff.c:1089
skb_release_data+0x6c5/0x8e0 net/core/skbuff.c:1116
skb_release_all net/core/skbuff.c:1191 [inline]
__kfree_skb net/core/skbuff.c:1205 [inline]
kfree_skb_partial+0xb0/0xf0 net/core/skbuff.c:6154
tcp_add_backlog+0x149e/0x2250 net/ipv4/tcp_ipv4.c:2004
tcp_v4_rcv+0x3814/0x4840 net/ipv4/tcp_ipv4.c:2250
ip_protocol_deliver_rcu+0xba/0x4d0 net/ipv4/ip_input.c:207
ip_local_deliver_finish+0x3f2/0x6e0 net/ipv4/ip_input.c:241
NF_HOOK include/linux/netfilter.h:318 [inline]
NF_HOOK include/linux/netfilter.h:312 [inline]
ip_local_deliver+0x19a/0x1f0 net/ipv4/ip_input.c:262
dst_input include/net/dst.h:480 [inline]
ip_sublist_rcv_finish net/ipv4/ip_input.c:623 [inline]
ip_list_rcv_finish+0xa14/0xce0 net/ipv4/ip_input.c:675
ip_sublist_rcv net/ipv4/ip_input.c:683 [inline]
ip_list_rcv+0x338/0x450 net/ipv4/ip_input.c:717
__netif_receive_skb_list_ptype net/core/dev.c:6255 [inline]
__netif_receive_skb_list_core+0x74c/0x940 net/core/dev.c:6302
__netif_receive_skb_list net/core/dev.c:6354 [inline]
netif_receive_skb_list_internal+0x722/0xd40 net/core/dev.c:6445
gro_normal_list include/net/gro.h:523 [inline]
gro_normal_list include/net/gro.h:519 [inline]
gro_flush_normal include/net/gro.h:531 [inline]
napi_complete_done+0x221/0x940 net/core/dev.c:6813
virtqueue_napi_complete drivers/net/virtio_net.c:740 [inline]
virtnet_poll+0x1c12/0x3a90 drivers/net/virtio_net.c:3027
__napi_poll.constprop.0+0xaf/0x450 net/core/dev.c:7735
napi_poll net/core/dev.c:7798 [inline]
net_rx_action+0xa40/0xf20 net/core/dev.c:7955
handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
common_interrupt+0xbe/0xe0 arch/x86/kernel/irq.c:273
asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:665
RIP: 0010:lock_acquire+0x5e/0x370 kernel/locking/lockdep.c:5872
Code: 05 fb 4d 7e 12 83 f8 07 0f 87 da 00 00 00 48 0f a3 05 86 81 3c 0f 0f 82 ac 02 00 00 8b 35 4e b5 3c 0f 85 f6 0f 85 c7 00 00 00 <48> 8b 44 24 30 65 48 2b 05 9d 4d 7e 12 0f 85 ec 02 00 00 48 83 c4
RSP: 0018:ffffc9000369f280 EFLAGS: 00000206
RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8e17fc5f RDI: ffffffff8c401580
RBP: ffffffff8ebe8180 R08: 00000000205ecd38 R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
rcu_read_lock include/linux/rcupdate.h:840 [inline]
class_rcu_constructor include/linux/rcupdate.h:1183 [inline]
unwind_next_frame+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495
__unwind_start+0x3cd/0x7e0 arch/x86/kernel/unwind_orc.c:787
unwind_start arch/x86/include/asm/unwind.h:64 [inline]
arch_stack_walk+0x73/0xf0 arch/x86/kernel/stacktrace.c:24
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x30/0x50 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:4584 [inline]
slab_alloc_node mm/slub.c:4917 [inline]
kmem_cache_alloc_node_noprof+0x27d/0x6b0 mm/slub.c:4989
__alloc_skb+0x140/0x710 net/core/skbuff.c:704
alloc_skb_fclone include/linux/skbuff.h:1434 [inline]
tcp_stream_alloc_skb+0x34/0x660 net/ipv4/tcp.c:931
tso_fragment net/ipv4/tcp_output.c:2410 [inline]
tcp_write_xmit+0x732/0x8470 net/ipv4/tcp_output.c:3048
tcp_sendmsg_locked+0x2c8c/0x44d0 net/ipv4/tcp.c:1394
tcp_sendmsg+0x2e/0x50 net/ipv4/tcp.c:1451
inet_sendmsg+0xb9/0x140 net/ipv4/af_inet.c:865
sock_sendmsg_nosec net/socket.c:775 [inline]
__sock_sendmsg net/socket.c:790 [inline]
sock_write_iter+0x4ea/0x5b0 net/socket.c:1241
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6ac/0x1050 fs/read_write.c:687
ksys_write+0x1f8/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8fc4159017
Code: 48 89 fa 4c 89 df e8 a8 56 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffc2f6c81a0 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000555585a6b540 RCX: 00007f8fc4159017
RDX: 0000000000055f08 RSI: 00007f8fc01aa0f8 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000055f08
R13: 0000555585a7f8a0 R14: 00007ffc2f6c8780 R15: 00007f8fc01aa0f8
task:kworker/u8:6 state:R running task stack:25776 pid:913 tgid:913 ppid:2 task_flags:0x4208160 flags:0x00080000
Workqueue: events_unbound cfg80211_wiphy_work
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7556
irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline]
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
irqentry_exit+0x205/0xa00 kernel/entry/common.c:167
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:679
RIP: 0010:rcu_is_watching+0x80/0xc0 kernel/rcu/tree.c:753
Code: 89 da 48 c1 ea 03 0f b6 14 02 48 89 d8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 24 8b 03 c1 e8 02 83 e0 01 65 ff 0d c0 db 75 12 <74> 07 5b 5d c3 cc cc cc cc e8 42 88 87 ff 5b 5d e9 db ec cf 09 48
RSP: 0018:ffffc9000437f678 EFLAGS: 00000286
RAX: 0000000000000001 RBX: ffff8880b8533c68 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8c401500 RDI: ffffffff8e46d928
RBP: 0000000000000001 R08: 0000000044911634 R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000000000 R12: ffffffff81f46ee0
R13: ffffc9000437f700 R14: 0000000000000000 R15: ffff88802717a540
rcu_read_lock include/linux/rcupdate.h:841 [inline]
class_rcu_constructor include/linux/rcupdate.h:1183 [inline]
unwind_next_frame+0x6fa/0x2090 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
kasan_save_free_info+0x3b/0x70 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:2677 [inline]
slab_free mm/slub.c:6377 [inline]
kfree+0x22b/0x6c0 mm/slub.c:6692
skb_kfree_head net/core/skbuff.c:1077 [inline]
skb_free_head+0xb9/0x160 net/core/skbuff.c:1089
skb_release_data+0x6c5/0x8e0 net/core/skbuff.c:1116
skb_release_all net/core/skbuff.c:1191 [inline]
__kfree_skb net/core/skbuff.c:1205 [inline]
consume_skb net/core/skbuff.c:1439 [inline]
consume_skb+0xc4/0x110 net/core/skbuff.c:1433
ieee80211_iface_work+0x355/0x1070 net/mac80211/iface.c:1825
cfg80211_wiphy_work+0x2b7/0x550 net/wireless/core.c:538
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
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: rcu_preempt kthread starved for 7709 jiffies! g12945 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:28984 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7326
schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123
rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325
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: 0 UID: 0 PID: 1180 Comm: kworker/u8:9 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0x593/0x1870 kernel/smp.c:912
Code: 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 64 99 0c 00 f3 90 41 0f b6 45 00 <41> 38 c4 7c 08 84 c0 0f 85 a8 10 00 00 8b 45 08 31 ff 83 e0 01 41
RSP: 0018:ffffc90005516848 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff81fdc702
RDX: ffff88802a4f8000 RSI: ffffffff81fdc6dc RDI: ffff88802a4f8000
RBP: ffff8880b8541240 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003
R13: ffffed10170a8249 R14: 0000000000000001 R15: ffff8880b843c880
FS: 0000000000000000(0000) GS:ffff888123ddc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd673fef4b8 CR3: 00000000608df000 CR4: 00000000003526f0
Call Trace:
on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1077
__flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline]
flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline]
flush_tlb_mm_range+0x45f/0x16f0 arch/x86/mm/tlb.c:1451
flush_tlb_page arch/x86/include/asm/tlbflush.h:345 [inline]
ptep_clear_flush+0x148/0x170 mm/pgtable-generic.c:104
page_vma_mkclean_one.constprop.0+0x3a2/0x7b0 mm/rmap.c:1138
page_mkclean_one+0x1cd/0x2b0 mm/rmap.c:1186
__rmap_walk_file+0x383/0x680 mm/rmap.c:3064
rmap_walk_file+0x1d8/0x2a0 mm/rmap.c:3097
rmap_walk mm/rmap.c:3108 [inline]
folio_mkclean+0x2af/0x4e0 mm/rmap.c:1218
folio_clear_dirty_for_io+0x1ba/0x960 mm/page-writeback.c:2909
mpage_submit_folio+0x84/0x330 fs/ext4/inode.c:2085
mpage_map_and_submit_buffers+0x5f2/0xb50 fs/ext4/inode.c:2347
mpage_map_and_submit_extent fs/ext4/inode.c:2537 [inline]
ext4_do_writepages+0x23a4/0x3ed0 fs/ext4/inode.c:2949
ext4_writepages+0x347/0x750 fs/ext4/inode.c:3043
do_writepages+0x278/0x600 mm/page-writeback.c:2571
__writeback_single_inode+0x164/0x1300 fs/fs-writeback.c:1787
writeback_sb_inodes+0x766/0x1c50 fs/fs-writeback.c:2079
__writeback_inodes_wb+0xf8/0x2d0 fs/fs-writeback.c:2155
wb_writeback+0x6f6/0xb50 fs/fs-writeback.c:2266
wb_check_old_data_flush fs/fs-writeback.c:2370 [inline]
wb_do_writeback fs/fs-writeback.c:2449 [inline]
wb_workfn+0x93f/0xc80 fs/fs-writeback.c:2477
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
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