rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P12794/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=49917, q=1911 ncpus=2)
task:syz.0.1945 state:R running task stack:27336 pid:12794 tgid:12792 ppid:5832 task_flags:0x400040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6961
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288
irqentry_exit+0x6f/0x90 kernel/entry/common.c:197
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:32 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:127 [inline]
RIP: 0010:lock_acquire+0xd5/0x360 kernel/locking/lockdep.c:5864
Code: 8b 04 25 08 40 f6 91 83 b8 1c 0b 00 00 00 0f 85 d5 00 00 00 48 c7 44 24 30 00 00 00 00 9c 8f 44 24 30 4c 89 74 24 10 4d 89 fe <4c> 8b 7c 24 30 fa 48 c7 c7 87 e0 04 8d e8 c9 28 5b 09 65 ff 05 32
RSP: 0018:ffffc9000503f238 EFLAGS: 00000246
RAX: ffff888031fb1dc0 RBX: 0000000000000000 RCX: 7206e1d954164f00
RDX: 0000000000000000 RSI: ffffffff8172c182 RDI: 1ffffffff1b351b0
RBP: ffffffff8172c165 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc9000503f3f8 R11: ffffffff81aaf310 R12: 0000000000000002
R13: ffffffff8d9a8d80 R14: 0000000000000000 R15: 0000000000000000
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:841 [inline]
class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
unpoison_slab_object mm/kasan/common.c:330 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:356
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4191 [inline]
slab_alloc_node mm/slub.c:4240 [inline]
kmem_cache_alloc_lru_noprof+0x14c/0x310 mm/slub.c:4259
__d_alloc+0x36/0x7b0 fs/dcache.c:1690
d_alloc_parallel+0xe5/0x1600 fs/dcache.c:2549
__lookup_slow+0x11c/0x3d0 fs/namei.c:1793
simple_start_creating+0xfd/0x1e0 fs/libfs.c:2303
start_creating+0x10f/0x180 fs/debugfs/inode.c:396
__debugfs_create_file+0x79/0x4f0 fs/debugfs/inode.c:431
debugfs_create_file_full+0x3f/0x60 fs/debugfs/inode.c:468
kvm_create_vm_debugfs+0x459/0x900 virt/kvm/kvm_main.c:1061
kvm_create_vm virt/kvm/kvm_main.c:1204 [inline]
kvm_dev_ioctl_create_vm virt/kvm/kvm_main.c:5480 [inline]
kvm_dev_ioctl+0x15a0/0x1980 virt/kvm/kvm_main.c:5522
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:598 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:584
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe10674eec9
RSP: 002b:00007fe1049ae038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fe1069a5fa0 RCX: 00007fe10674eec9
RDX: 0000000000000000 RSI: 000000000000ae01 RDI: 0000000000000003
RBP: 00007fe1067d1f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe1069a6038 R14: 00007fe1069a5fa0 R15: 00007ffe323b8218
rcu: rcu_preempt kthread starved for 4392 jiffies! g49917 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:26968 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7058
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: 13 b3 03 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 13 26 11 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8d607d80 EFLAGS: 000002c6
RAX: 127b76fe0776f800 RBX: ffffffff81955f48 RCX: 127b76fe0776f800
RDX: 0000000000000001 RSI: ffffffff8d03ad79 RDI: ffffffff8b621680
RBP: ffffffff8d607eb8 R08: ffff8880b883341b R09: 1ffff11017106683
R10: dffffc0000000000 R11: ffffed1017106684 R12: ffffffff8f1d6330
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1ae0620
FS: 0000000000000000(0000) GS:ffff8881268bc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f52909efa75 CR3: 0000000048bb2000 CR4: 00000000003526f0
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:757
default_idle_call+0x74/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:190 [inline]
do_idle+0x1e8/0x510 kernel/sched/idle.c:330
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
rest_init+0x2de/0x300 init/main.c:744
start_kernel+0x3a9/0x410 init/main.c:1097
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:307
x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:288
common_startup_64+0x13e/0x147