rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P16/3:b..l P7598/4:b..l
rcu: (detected by 0, t=10502 jiffies, g=21817, q=3863 ncpus=2)
task:syz.3.485 state:D stack:25000 pid:7598 tgid:7597 ppid:5802 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule_rtlock+0x30/0x70 kernel/sched/core.c:7090
rtlock_slowlock_locked+0x3819/0x4010 kernel/locking/rtmutex.c:1868
rtlock_slowlock kernel/locking/rtmutex.c:1895 [inline]
rtlock_lock kernel/locking/spinlock_rt.c:43 [inline]
__rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline]
rt_spin_lock+0x158/0x3e0 kernel/locking/spinlock_rt.c:57
spin_lock_bh include/linux/spinlock_rt.h:88 [inline]
hrtimer_cancel_wait_running+0xfa/0x180 kernel/time/hrtimer.c:1453
hrtimer_cancel+0x39/0x60 kernel/time/hrtimer.c:1484
__disable_vblank drivers/gpu/drm/drm_vblank.c:442 [inline]
drm_vblank_disable_and_save+0x1bf/0x380 drivers/gpu/drm/drm_vblank.c:481
drm_crtc_vblank_off+0x22e/0x820 drivers/gpu/drm/drm_vblank.c:1364
crtc_disable drivers/gpu/drm/drm_atomic_helper.c:1261 [inline]
disable_outputs drivers/gpu/drm/drm_atomic_helper.c:1344 [inline]
drm_atomic_helper_commit_modeset_disables+0xc99/0x2040 drivers/gpu/drm/drm_atomic_helper.c:1529
vkms_atomic_commit_tail+0x51/0x210 drivers/gpu/drm/vkms/vkms_drv.c:61
commit_tail+0x284/0x3a0 drivers/gpu/drm/drm_atomic_helper.c:1993
drm_atomic_helper_commit+0xa6b/0xb10 drivers/gpu/drm/drm_atomic_helper.c:2233
drm_atomic_commit+0x262/0x2c0 drivers/gpu/drm/drm_atomic.c:1577
drm_atomic_helper_set_config+0xe2/0x160 drivers/gpu/drm/drm_atomic_helper.c:3433
drm_mode_setcrtc+0x9a7/0x1c50 drivers/gpu/drm/drm_crtc.c:869
drm_ioctl_kernel+0x2d2/0x3a0 drivers/gpu/drm/drm_ioctl.c:797
drm_ioctl+0x685/0xb20 drivers/gpu/drm/drm_ioctl.c:894
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xff/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fab9558f749
RSP: 002b:00007fab937f6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fab957e5fa0 RCX: 00007fab9558f749
RDX: 0000200000000400 RSI: 00000000c06864a2 RDI: 0000000000000003
RBP: 00007fab95613f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fab957e6038 R14: 00007fab957e5fa0 R15: 00007ffc3a1a9458
task:ktimers/0 state:D stack:22992 pid:16 tgid:16 ppid:2 task_flags:0x4208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule_rtlock+0x30/0x70 kernel/sched/core.c:7090
rtlock_slowlock_locked+0x3819/0x4010 kernel/locking/rtmutex.c:1868
rtlock_slowlock kernel/locking/rtmutex.c:1895 [inline]
rtlock_lock kernel/locking/spinlock_rt.c:43 [inline]
__rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline]
rt_spin_lock+0x158/0x3e0 kernel/locking/spinlock_rt.c:57
spin_lock include/linux/spinlock_rt.h:44 [inline]
drm_handle_vblank+0xc1/0x630 drivers/gpu/drm/drm_vblank.c:1930
vkms_vblank_simulate+0x97/0x2f0 drivers/gpu/drm/vkms/vkms_crtc.c:30
__run_hrtimer kernel/time/hrtimer.c:1777 [inline]
__hrtimer_run_queues+0x552/0xd40 kernel/time/hrtimer.c:1841
hrtimer_run_softirq+0x1a3/0x2e0 kernel/time/hrtimer.c:1858
handle_softirqs+0x22f/0x710 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
run_ktimerd+0xcf/0x190 kernel/softirq.c:1138
smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g21817 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=10462
rcu: rcu_preempt kthread starved for 10502 jiffies! g21817 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26888 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7026
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+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 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: 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 10/25/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: cc cc cc cc 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 63 a7 27 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:ffffffff8d207d80 EFLAGS: 000002c2
RAX: be1e2bebc89cdc00 RBX: ffffffff81953c47 RCX: be1e2bebc89cdc00
RDX: 0000000000000001 RSI: ffffffff8cd8e759 RDI: ffffffff8b3ddfe0
RBP: ffffffff8d207ea8 R08: ffff8880b88334db R09: 1ffff1101710669b
R10: dffffc0000000000 R11: ffffed101710669c R12: ffffffff8ed64270
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1a60640
FS: 0000000000000000(0000) GS:ffff888126df6000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f39e9bc3d84 CR3: 000000003980a000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:190 [inline]
do_idle+0x1e7/0x510 kernel/sched/idle.c:330
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
rest_init+0x2de/0x300 init/main.c:757
start_kernel+0x3ae/0x410 init/main.c:1111
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x147