rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 ticks this GP) idle=f4ac/1/0x4000000000000000 softirq=310627/310627 fqs=6
rcu: (detected by 1, t=10504 jiffies, g=345433, q=1336 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 12591 Comm: syz.4.20782 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:advance_sched+0xb24/0xc80 net/sched/sch_taprio.c:997
Code: c2 a0 56 28 8d e8 9c 85 b5 f7 48 c7 c7 20 c9 d5 8e 48 89 de e8 2d 6a b5 f7 e8 b8 20 bf f7 b8 01 00 00 00 48 81 c4 90 00 00 00 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 98 42 22 f7 cc e8 87 dd d9 f7 e9
RSP: 0018:ffffc90000007d88 EFLAGS: 00000086
RAX: 0000000000000001 RBX: ffffffff89edfd28 RCX: 0000000001000001
RDX: 0000000001000001 RSI: ffffffff8e69da56 RDI: ffff88807811be80
RBP: 0000000000000001 R08: 0000000001000001 R09: 1ffff110056f5e33
R10: dffffc0000000000 R11: ffffed10056f5e34 R12: ffff888031b2ac00
R13: ffff88802b7af000 R14: dffffc0000000000 R15: ffff88802b7af340
FS: 00007feb79de86c0(0000) GS:ffff888124ccb000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002000 CR3: 0000000088e40000 CR4: 0000000000350ef0
Call Trace:
__run_hrtimer kernel/time/hrtimer.c:2074 [inline]
__hrtimer_run_queues+0x3bc/0xa10 kernel/time/hrtimer.c:2131
hrtimer_interrupt+0x4cd/0xaa0 kernel/time/hrtimer.c:2250
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
__sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1068
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:csd_lock_wait kernel/smp.c:363 [inline]
RIP: 0010:smp_call_function_many_cond+0x1137/0x1500 kernel/smp.c:1002
Code: 89 ee 83 e6 01 31 ff e8 27 4b 0c 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 12 46 0c 00 eb 35 f3 90 43 0f b6 04 2c <84> c0 75 0f f7 03 01 00 00 00 74 1d e8 f8 45 0c 00 eb e6 89 d9 80
RSP: 0018:ffffc9000e40fac0 EFLAGS: 00000287
RAX: 0000000000000000 RBX: ffff8880b87414c8 RCX: 0000000000080000
RDX: ffffc90010f98000 RSI: 0000000000005326 RDI: 0000000000005327
RBP: ffffc9000e40fc10 R08: ffffffff907a517f R09: 1ffffffff20f4a2f
R10: dffffc0000000000 R11: ffffffff81756120 R12: 1ffff110170e8299
R13: dffffc0000000000 R14: 1ffff1100f023a83 R15: 0000000000000001
clock_was_set+0x7c6/0x890 kernel/time/hrtimer.c:1002
do_settimeofday64+0x34e/0x590 kernel/time/timekeeping.c:1730
__do_sys_clock_settime kernel/time/posix-timers.c:1139 [inline]
__se_sys_clock_settime kernel/time/posix-timers.c:1123 [inline]
__x64_sys_clock_settime+0x253/0x2a0 kernel/time/posix-timers.c:1123
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7feb78f9e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007feb79de8028 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3
RAX: ffffffffffffffda RBX: 00007feb79225fa0 RCX: 00007feb78f9e159
RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000000000000000
RBP: 00007feb7903506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007feb79226038 R14: 00007feb79225fa0 R15: 00007ffcbae86cd8
rcu: rcu_preempt kthread starved for 10470 jiffies! g345433 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->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:27496 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5533 [inline]
__schedule+0x17db/0x58f0 kernel/sched/core.c:7284
__schedule_loop kernel/sched/core.c:7361 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7376
schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2122
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2330
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 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: 1 UID: 0 PID: 12581 Comm: syz.3.20780 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:csd_lock_wait kernel/smp.c:363 [inline]
RIP: 0010:csd_lock kernel/smp.c:396 [inline]
RIP: 0010:smp_call_function_many_cond+0x628/0x1500 kernel/smp.c:944
Code: 00 44 8b 3b 44 89 fe 83 e6 01 31 ff e8 31 56 0c 00 41 83 e7 01 75 07 e8 26 51 0c 00 eb 3f f3 90 48 b8 00 00 00 00 00 fc ff df <41> 0f b6 04 04 84 c0 75 0f f7 03 01 00 00 00 74 1d e8 02 51 0c 00
RSP: 0018:ffffc9000d9df460 EFLAGS: 00000293
RAX: dffffc0000000000 RBX: ffff8880b8643708 RCX: ffff888035685dc0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000d9df5b0 R08: ffff88803568735f R09: 1ffff11006ad0e6b
R10: dffffc0000000000 R11: 0000000000000000 R12: 1ffff110170c86e1
R13: 0000000000000000 R14: ffff8880b8643700 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff888124dcb000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2f71eff8 CR3: 000000004ef60000 CR4: 0000000000350ef0
Call Trace:
__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+0x8ff/0x1090 arch/x86/mm/tlb.c:1435
tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:509 [inline]
tlb_flush_mmu+0x1af/0xa30 mm/mmu_gather.c:423
tlb_finish_mmu+0xf4/0x220 mm/mmu_gather.c:549
exit_mmap+0x4b2/0x9f0 mm/mmap.c:1328
__mmput+0x118/0x420 kernel/fork.c:1193
exit_mm+0x221/0x2d0 kernel/exit.c:618
do_exit+0x6cd/0x2360 kernel/exit.c:1000
do_group_exit+0x22d/0x2f0 kernel/exit.c:1155
get_signal+0x121b/0x12c0 kernel/signal.c:3112
arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop+0x10e/0x770 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline]
do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1856d9e159
Code: Unable to access opcode bytes at 0x7f1856d9e12f.
RSP: 002b:00007f1857cb50e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f1857025fa8 RCX: 00007f1856d9e159
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f1857025fa8
RBP: 00007f1857025fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1857026038 R14: 00007fffce4f4750 R15: 00007fffce4f4838