rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (1 GPs behind) idle=a8c4/1/0x4000000000000000 softirq=243493/243499 fqs=4
rcu: (detected by 0, t=10502 jiffies, g=193573, q=1166 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 1872 Comm: syz.4.6971 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:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x41/0xc0 kernel/rcu/tree.c:751
Code: b4 93 89 c5 83 f8 07 0f 87 82 00 00 00 48 8d 3c ed 20 cf d7 8d 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 <75> 5c 48 03 1c ed 20 cf d7 8d 48 b8 00 00 00 00 00 fc ff df 48 89
RSP: 0018:ffffc90000a08cf0 EFLAGS: 00000046
RAX: dffffc0000000000 RBX: ffffffff93b429e8 RCX: 0000000000000000
RDX: 1ffffffff1baf9e5 RSI: ffffffff8bf2b200 RDI: ffffffff8dd7cf28
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: ffff88808845d4b0 R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 00007fbf4b9a66c0(0000) GS:ffff8881249f1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffbaf7b42f8 CR3: 000000008e650000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
trace_lock_acquire include/trace/events/lock.h:24 [inline]
lock_acquire+0x2cd/0x330 kernel/locking/lockdep.c:5831
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
advance_sched+0xd9/0xc80 net/sched/sch_taprio.c:930
__run_hrtimer kernel/time/hrtimer.c:1777 [inline]
__hrtimer_run_queues+0x202/0xc40 kernel/time/hrtimer.c:1841
hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1903
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
__sysvec_apic_timer_interrupt+0x10b/0x3c0 arch/x86/kernel/apic/apic.c:1062
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 a6 64 1e f6 48 89 df e8 5e b7 1e f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 d5 b6 0e f6 65 8b 05 9e 4b 37 08 85 c0 74 16 5b
RSP: 0018:ffffc9000f11f170 EFLAGS: 00000246
RAX: 0000000000000002 RBX: ffff8880493b22a8 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff8dacf385 RDI: ffffffff8bf2b280
RBP: 0000000000000246 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff9088cbd7 R11: ffff88808845d4b0 R12: ffff8880493b2158
R13: 0000000000000000 R14: 00000233ddd575da R15: 0000000000000002
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
taprio_change+0x28ae/0x3a70 net/sched/sch_taprio.c:1986
taprio_init+0x690/0x910 net/sched/sch_taprio.c:2126
qdisc_create+0x457/0xfa0 net/sched/sch_api.c:1319
__tc_modify_qdisc net/sched/sch_api.c:1753 [inline]
tc_modify_qdisc+0x122f/0x2230 net/sched/sch_api.c:1817
rtnetlink_rcv_msg+0x3c9/0xe90 net/core/rtnetlink.c:6967
netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2550
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1894
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_sendmsg+0x16d/0x220 net/socket.c:2678
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: 0033:0x7fbf4ab8f749
Code: 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 01 48
RSP: 002b:00007fbf4b9a6038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fbf4ade6090 RCX: 00007fbf4ab8f749
RDX: 0000000000000000 RSI: 00002000000007c0 RDI: 0000000000000006
RBP: 00007fbf4ac13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbf4ade6128 R14: 00007fbf4ade6090 R15: 00007ffe872ae568
rcu: rcu_preempt kthread starved for 8087 jiffies! g193573 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:27904 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5260 [inline]
__schedule+0x1138/0x5ee0 kernel/sched/core.c:6867
__schedule_loop kernel/sched/core.c:6949 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6964
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: 1850 Comm: syz.5.6963 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:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xe02/0x15e0 kernel/smp.c:877
Code: 10 4c 89 74 24 10 49 89 d5 48 89 d5 48 89 54 24 18 49 c1 ed 03 83 e5 07 4d 01 e5 83 c5 03 e8 45 5f 0c 00 f3 90 41 0f b6 45 00 <40> 38 c5 7c 08 84 c0 0f 85 b6 05 00 00 8b 43 08 31 ff 83 e0 01 41
RSP: 0018:ffffc9000efd7360 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b8540cc0 RCX: ffffffff81b2a071
RDX: ffff88801e784980 RSI: ffffffff81b2a04b RDI: 0000000000000005
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: ffff88801e7854b0 R12: dffffc0000000000
R13: ffffed10170a8199 R14: 0000000000000001 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8881248f1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbed31b42f8 CR3: 0000000064943000 CR4: 00000000003526f0
Call Trace:
on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1043
__flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline]
flush_tlb_mm_range+0x2f0/0x12c0 arch/x86/mm/tlb.c:1472
tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:490 [inline]
tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:480 [inline]
zap_pte_range mm/memory.c:1881 [inline]
zap_pmd_range mm/memory.c:1946 [inline]
zap_pud_range mm/memory.c:1975 [inline]
zap_p4d_range mm/memory.c:1996 [inline]
unmap_page_range+0x1fd3/0x43c0 mm/memory.c:2017
unmap_single_vma+0x153/0x240 mm/memory.c:2059
unmap_vmas+0x218/0x470 mm/memory.c:2101
exit_mmap+0x1b0/0xb60 mm/mmap.c:1277
__mmput+0x12a/0x410 kernel/fork.c:1173
mmput+0x62/0x70 kernel/fork.c:1196
exit_mm kernel/exit.c:581 [inline]
do_exit+0x7d7/0x2bd0 kernel/exit.c:959
do_group_exit+0xd3/0x2a0 kernel/exit.c:1112
get_signal+0x2671/0x26d0 kernel/signal.c:3034
arch_do_signal_or_restart+0x8f/0x7e0 arch/x86/kernel/signal.c:337
__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: 0033:0x7f260238f34b
Code: Unable to access opcode bytes at 0x7f260238f321.
RSP: 002b:00007f260322bf00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffea RBX: 00007f2602710320 RCX: 00007f260238f34b
RDX: 00007f260271076c RSI: 0000000040095505 RDI: 0000000000000003
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000003 R11: 0000000000000246 R12: 00007f260271076e
R13: 00007f260271076c R14: 0000000000000000 R15: 0000000000000000