rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (1574 ticks this GP) idle=b0b/1/0x4000000000000000 softirq=13740/13740 fqs=1 
	(t=10500 jiffies g=18365 q=23058)
rcu: rcu_preempt kthread starved for 10373 jiffies! g18365 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27608 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571
 preempt_schedule+0xbc/0xd0 kernel/sched/core.c:6596
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
 _raw_spin_unlock_irqrestore+0x10d/0x120 kernel/locking/spinlock.c:194
 __debug_object_init+0x259/0xc80 lib/debugobjects.c:633
 init_timer_on_stack_key kernel/time/timer.c:752 [inline]
 schedule_timeout+0x12d/0x2d0 kernel/time/timer.c:2115
 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5859 Comm: syz.1.333 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:orc_ip arch/x86/kernel/unwind_orc.c:30 [inline]
RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:52 [inline]
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:178 [inline]
RIP: 0010:unwind_next_frame+0x1049/0x1d90 arch/x86/kernel/unwind_orc.c:448
Code: 89 37 e9 3f 01 00 00 49 89 d7 49 89 d5 4c 89 e0 4c 29 e8 48 89 c1 48 c1 f9 02 48 c1 e8 3f 48 01 c8 48 83 e0 fe 4d 8d 74 45 00 <4c> 89 f0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 84
RSP: 0018:ffffc900038ef7c8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffc900038ef888 RCX: 0000000000000000
RDX: ffffffff8dad505c RSI: ffffffff8e236778 RDI: ffffffff81351d2c
RBP: ffffffff83005585 R08: 0000000000000001 R09: 0000000000000005
R10: dffffc0000000000 R11: fffff5200071df1d R12: ffffffff8dad505c
R13: ffffffff8dad505c R14: ffffffff8dad505c R15: ffffffff8dad505c
FS:  00007f1b8e7bc6c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001000 CR3: 000000006733f000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1710 [inline]
 slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736
 slab_free mm/slub.c:3504 [inline]
 kfree+0xef/0x2a0 mm/slub.c:4564
 v9fs_mount+0xd6/0x850 fs/9p/vfs_super.c:196
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x24a/0xa40 fs/namespace.c:3034
 do_mount fs/namespace.c:3377 [inline]
 __do_sys_mount fs/namespace.c:3585 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f1b90583e59
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:00007f1b8e7bc028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f1b907fd090 RCX: 00007f1b90583e59
RDX: 00002000000006c0 RSI: 0000200000000680 RDI: 0000200000000000
RBP: 00007f1b90619d6f R08: 0000200000000080 R09: 0000000000000000
R10: 0000000000008010 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1b907fd128 R14: 00007f1b907fd090 R15: 00007fff475c1128
 </TASK>
NMI backtrace for cpu 0
CPU: 0 PID: 5860 Comm: syz.0.332 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
 <IRQ>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_dump_cpu_stacks+0x22f/0x380 kernel/rcu/tree_stall.h:349
 print_cpu_stall+0x31d/0x5f0 kernel/rcu/tree_stall.h:633
 check_cpu_stall kernel/rcu/tree_stall.h:727 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x6ea/0x1120 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:2021
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4b4/0xb70 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:console_unlock+0xcad/0x1120 kernel/printk/printk.c:2749
Code: 75 11 e8 f6 dc 18 00 4d 85 ff 75 16 e8 ec dc 18 00 eb 15 e8 e5 dc 18 00 e8 80 80 5c 08 4d 85 ff 74 ea e8 d6 dc 18 00 fb 31 ff <89> de e8 2c e0 18 00 85 db 0f 94 c0 22 44 24 17 3c 01 75 1f e8 ba
RSP: 0018:ffffc9000316f460 EFLAGS: 00000246
RAX: ffffffff8160593a RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc900060fa000 RSI: 000000000007ffff RDI: 0000000000000000
RBP: ffffc9000316f6d0 R08: ffffffff901d60c7 R09: 1ffffffff203ac18
R10: dffffc0000000000 R11: fffffbfff203ac19 R12: 1ffffffff198d829
R13: 000000000000005e R14: 0000000000000000 R15: 0000000000000200
 vprintk_emit+0xc0/0x150 kernel/printk/printk.c:2274
 _printk+0xda/0x130 kernel/printk/printk.c:2299
 p9_fd_create_tcp+0x514/0x600 net/9p/trans_fd.c:1035
 p9_client_create+0x84a/0x1010 net/9p/client.c:1044
 v9fs_session_init+0x1f0/0x1830 fs/9p/v9fs.c:409
 v9fs_mount+0x72/0x850 fs/9p/vfs_super.c:126
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x24a/0xa40 fs/namespace.c:3034
 do_mount fs/namespace.c:3377 [inline]
 __do_sys_mount fs/namespace.c:3585 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fabc7dc6e59
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:00007fabc5fff028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fabc8040090 RCX: 00007fabc7dc6e59
RDX: 00002000000006c0 RSI: 0000200000000680 RDI: 0000200000000000
RBP: 00007fabc7e5cd6f R08: 0000200000000080 R09: 0000000000000000
R10: 0000000000008010 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fabc8040128 R14: 00007fabc8040090 R15: 00007ffe8b6adca8
 </TASK>