rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P38/1:b..l
rcu: (detected by 1, t=10503 jiffies, g=25133, q=1561 ncpus=2)
task:khugepaged state:R running task stack:27080 pid:38 tgid:38 ppid:2 task_flags:0x200040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6863
preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:7047
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__folio_batch_add_and_move+0x5e2/0xc30 mm/swap.c:201
folio_putback_lru+0x1c/0xd0 mm/vmscan.c:847
__collapse_huge_page_copy_succeeded mm/khugepaged.c:715 [inline]
__collapse_huge_page_copy mm/khugepaged.c:810 [inline]
collapse_huge_page+0x22b7/0x3420 mm/khugepaged.c:1214
hpage_collapse_scan_pmd+0xd4b/0x13d0 mm/khugepaged.c:1407
khugepaged_scan_mm_slot mm/khugepaged.c:2486 [inline]
khugepaged_do_scan mm/khugepaged.c:2570 [inline]
khugepaged+0x1228/0x1690 mm/khugepaged.c:2626
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: rcu_preempt kthread starved for 10449 jiffies! g25133 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:28440 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
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:constant_test_bit arch/x86/include/asm/bitops.h:202 [inline]
RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:232 [inline]
RIP: 0010:tif_test_bit include/linux/thread_info.h:197 [inline]
RIP: 0010:tif_need_resched include/linux/thread_info.h:213 [inline]
RIP: 0010:need_resched include/linux/sched.h:2203 [inline]
RIP: 0010:preempt_schedule_common+0x50/0xc0 kernel/sched/core.c:7055
Code: 6d 39 08 65 8b 05 00 6d 39 08 25 ff ff ff 7f 83 f8 01 74 29 bf 01 00 00 00 e8 2c 99 ff ff 65 ff 0d e5 6c 39 08 80 3b 00 75 5f <48> 8b 45 00 a8 10 75 ca 5b 5d 41 5c 41 5d e9 3d f0 01 00 4c 8b 64
RSP: 0018:ffffc90000157978 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffed1003b53000 RCX: 1ffff9200002af1c
RDX: 0000000000000000 RSI: ffffffff8bf2b300 RDI: ffffffff8dd7bf28
RBP: ffff88801da98000 R08: 0000000000000000 R09: fffffbfff211167a
R10: ffffffff9088b3d7 R11: ffff88801da98b30 R12: ffffffff812c06c6
R13: ffff88801da98000 R14: ffff8880b84262c0 R15: 00000000ffffffff
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
_raw_spin_unlock_irqrestore+0x61/0x80 kernel/locking/spinlock.c:194
__mod_timer+0x8ed/0xd30 kernel/time/timer.c:1139
add_timer+0x62/0x90 kernel/time/timer.c:1249
schedule_timeout+0x11e/0x290 kernel/time/sleep_timeout.c:98
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: 1 UID: 0 PID: 8250 Comm: syz.2.513 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:lock_release+0x183/0x2d0 kernel/locking/lockdep.c:5893
Code: 0f c1 05 48 01 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 dd b9 18 12 0f 85 32 01 00 00 48 83 c4 18 5b 41 5c 41
RSP: 0018:ffffc90000a08540 EFLAGS: 00000206
RAX: 7410f1f66a6d2d00 RBX: ffffffff8e3c9620 RCX: ffffc90000a0854c
RDX: 0000000000000002 RSI: ffffffff8daa7d80 RDI: ffffffff8bf2b380
RBP: 0000000000000001 R08: 0000000000000001 R09: 00000000d7d2bc4e
R10: 0000000000000002 R11: 000000000001288f R12: ffffffff816cb9a4
R13: 0000000000000206 R14: ffff888053b54980 R15: 0000000000000003
FS: 00007f571bfb76c0(0000) GS:ffff8881249f5000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 0000000055280000 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:56
kasan_save_track+0x14/0x30 mm/kasan/common.c:77
unpoison_slab_object mm/kasan/common.c:339 [inline]
__kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:365
kasan_slab_alloc include/linux/kasan.h:252 [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
skb_copy+0x1c9/0x3a0 net/core/skbuff.c:2162
mac80211_hwsim_tx_frame_no_nl.isra.0+0xb6e/0x13c0 drivers/net/wireless/virtual/mac80211_hwsim.c:1891
mac80211_hwsim_tx_frame+0x1f1/0x2a0 drivers/net/wireless/virtual/mac80211_hwsim.c:2264
__mac80211_hwsim_beacon_tx drivers/net/wireless/virtual/mac80211_hwsim.c:2281 [inline]
mac80211_hwsim_beacon_tx+0x595/0xa40 drivers/net/wireless/virtual/mac80211_hwsim.c:2365
__iterate_interfaces+0x2e5/0x650 net/mac80211/util.c:761
ieee80211_iterate_active_interfaces_atomic+0x71/0x1b0 net/mac80211/util.c:797
mac80211_hwsim_beacon+0x105/0x1b0 drivers/net/wireless/virtual/mac80211_hwsim.c:2395
__run_hrtimer kernel/time/hrtimer.c:1777 [inline]
__hrtimer_run_queues+0x202/0xc40 kernel/time/hrtimer.c:1841
hrtimer_run_softirq+0x17d/0x350 kernel/time/hrtimer.c:1858
handle_softirqs+0x219/0x950 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x109/0x170 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline]
RIP: 0010:__might_sleep+0x10/0x150 kernel/sched/core.c:8744
Code: 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 b8 00 00 00 00 00 fc ff df 41 54 <65> 4c 8b 25 20 5e 28 12 55 89 f5 53 48 89 fb 49 8d 7c 24 18 48 89
RSP: 0018:ffffc900053d7aa8 EFLAGS: 00000202
RAX: dffffc0000000000 RBX: ffffffff8b86f660 RCX: ffffffff820b9392
RDX: ffff888053b54980 RSI: 0000000000000097 RDI: ffffffff8b86f660
RBP: 0000000000000097 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 000000000007fffc R12: 0000000000000000
R13: ffff888053b56380 R14: ffff888053b56384 R15: ffff888053b54980
__might_fault+0x83/0x190 mm/memory.c:7172
__copy_to_user include/linux/uaccess.h:151 [inline]
save_xstate_epilog arch/x86/kernel/fpu/signal.c:121 [inline]
copy_fpstate_to_sigframe+0x822/0xad0 arch/x86/kernel/fpu/signal.c:232
get_sigframe+0x4a8/0x9c0 arch/x86/kernel/signal.c:163
x64_setup_rt_frame+0x129/0xcf0 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+0x5da/0x7e0 arch/x86/kernel/signal.c:339
__exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
exit_to_user_mode_loop+0x8c/0x540 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+0x4ee/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f571b18f747
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:00007f571bfb70e8 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007f571b3e5fa8 RCX: 00007f571b18f749
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f571b3e5fa8
RBP: 00007f571b3e5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f571b3e6038 R14: 00007ffd2992dd70 R15: 00007ffd2992de58
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5171 Comm: syslogd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__kernel_text_address+0xd/0x40 kernel/extable.c:79
Code: e8 68 98 a2 00 e9 6a ff ff ff 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 53 48 89 fb e8 e3 fe ff ff <85> c0 75 1b 48 81 fb 00 90 06 92 72 0c 31 c0 48 81 fb 6a b8 28 92
RSP: 0018:ffffc90003eff538 EFLAGS: 00000286
RAX: 0000000000000001 RBX: ffffffff8228bf0b RCX: ffffc90003eff4b4
RDX: 1ffff920007dfeb5 RSI: ffffffff8daa7d80 RDI: ffffffff8228bf0b
RBP: ffffc90003eff5a8 R08: ffffffff912fbc54 R09: 00000000fce29622
R10: 0000000000000002 R11: 000000000001288a R12: ffffffff81a960d0
R13: ffffc90003eff620 R14: 0000000000000000 R15: ffff88807c310000
FS: 00007f875aacec80(0000) GS:ffff8881249f5000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005650be4930c8 CR3: 0000000032ec1000 CR4: 00000000003526f0
Call Trace:
unwind_get_return_address+0x59/0xa0 arch/x86/kernel/unwind_orc.c:385
arch_stack_walk+0xa6/0x100 arch/x86/kernel/stacktrace.c:26
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
kasan_save_track+0x14/0x30 mm/kasan/common.c:77
kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:252 [inline]
__kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284
kasan_slab_free include/linux/kasan.h:234 [inline]
slab_free_hook mm/slub.c:2540 [inline]
slab_free mm/slub.c:6668 [inline]
kfree+0x2f8/0x6e0 mm/slub.c:6876
skb_kfree_head net/core/skbuff.c:1068 [inline]
skb_free_head+0x114/0x210 net/core/skbuff.c:1080
skb_release_data+0x795/0x9e0 net/core/skbuff.c:1107
skb_release_all net/core/skbuff.c:1182 [inline]
__kfree_skb net/core/skbuff.c:1196 [inline]
consume_skb net/core/skbuff.c:1428 [inline]
consume_skb+0xbf/0x100 net/core/skbuff.c:1422
__unix_dgram_recvmsg+0x779/0xc30 net/unix/af_unix.c:2658
unix_dgram_recvmsg+0xd0/0x110 net/unix/af_unix.c:2675
sock_recvmsg_nosec net/socket.c:1078 [inline]
sock_recvmsg+0x1f9/0x250 net/socket.c:1100
sock_read_iter+0x2b9/0x3b0 net/socket.c:1170
new_sync_read fs/read_write.c:491 [inline]
vfs_read+0xa98/0xcf0 fs/read_write.c:572
ksys_read+0x1f8/0x250 fs/read_write.c:715
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: 0033:0x7f875ac1e407
Code: 48 89 fa 4c 89 df e8 38 aa 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:00007ffe562940a0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f875aacec80 RCX: 00007f875ac1e407
RDX: 00000000000000ff RSI: 0000557cb2db5300 RDI: 0000000000000000
RBP: 0000557cb2db52c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000557cb2db534e
R13: 0000000000000000 R14: 0000557cb2db5300 R15: 0000557c9c1b0d98