rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P11218/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=28537, q=780 ncpus=2)
task:syz.1.1471 state:R running task stack:26184 pid:11218 tgid:11215 ppid:5805 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0xfee/0x6120 kernel/sched/core.c:6911
preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7238
irqentry_exit+0x17b/0x670 kernel/entry/common.c:239
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x5e/0x380 kernel/locking/lockdep.c:5872
Code: 05 7b eb 28 12 83 f8 07 0f 87 f0 00 00 00 48 0f a3 05 46 9f f4 0e 0f 82 c2 02 00 00 8b 35 2e d3 f4 0e 85 f6 0f 85 dd 00 00 00 <48> 8b 44 24 30 65 48 2b 05 1d eb 28 12 0f 85 02 03 00 00 48 83 c4
RSP: 0018:ffffc9000570f6e8 EFLAGS: 00000206
RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8de51025 RDI: ffffffff8c1b0a20
RBP: ffffffff8e7e76a0 R08: 000000006ef1196c R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
rcu_read_lock include/linux/rcupdate.h:850 [inline]
class_rcu_constructor include/linux/rcupdate.h:1193 [inline]
unwind_next_frame+0xd1/0x1ea0 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
unpoison_slab_object mm/kasan/common.c:340 [inline]
__kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4538 [inline]
kmem_cache_alloc_bulk_noprof+0x39b/0x950 mm/slub.c:7288
__io_alloc_req_refill+0x9e/0x330 io_uring/io_uring.c:965
io_alloc_req io_uring/io_uring.h:508 [inline]
io_submit_sqes.cold+0xd5/0x2db io_uring/io_uring.c:2032
__do_sys_io_uring_enter+0x9c0/0x1a20 io_uring/io_uring.c:2604
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc15bb9c799
RSP: 002b:00007fc15c9e0028 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 00007fc15be15fa0 RCX: 00007fc15bb9c799
RDX: 00000000000044c1 RSI: 0000000000000d44 RDI: 0000000000000003
RBP: 00007fc15bc32c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000007 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc15be16038 R14: 00007fc15be15fa0 R15: 00007ffe7c5d3498
rcu: rcu_preempt kthread starved for 10518 jiffies! g28537 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:27832 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0xfee/0x6120 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7008
schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x754/0xd80 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:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 11223 Comm: vhost-11222 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:preempt_count_sub+0x3b/0x160 kernel/sched/core.c:5793
Code: 00 00 00 00 fc ff df 48 89 c1 83 e0 07 48 c1 e9 03 83 c0 03 0f b6 14 11 38 d0 7c 08 84 d2 0f 85 d9 00 00 00 8b 0d 55 f5 47 19 <85> c9 75 1b 65 8b 05 ba 71 38 12 89 c2 81 e2 ff ff ff 7f 39 d3 7f
RSP: 0018:ffffc90008db7a40 EFLAGS: 00000297
RAX: 0000000000000003 RBX: 0000000000000001 RCX: 0000000000000000
RDX: 0000000000000004 RSI: ffffffff8c1b09a0 RDI: 0000000000000001
RBP: ffffc90008db7bd0 R08: 0000000000000000 R09: fffffbfff21b3282
R10: ffffffff90d99417 R11: 0000000000000000 R12: ffff8880340a8000
R13: 0000000000000000 R14: dffffc0000000000 R15: ffff8880340a8000
FS: 00007f07ae11e6c0(0000) GS:ffff888124442000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000002 CR3: 000000004a152000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 000000000000000e DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
__mutex_lock_common kernel/locking/mutex.c:624 [inline]
__mutex_lock+0x26a/0x1b90 kernel/locking/mutex.c:776
vhost_vsock_handle_tx_kick+0xd1/0xdc0 drivers/vhost/vsock.c:505
vhost_run_work_list+0x183/0x220 drivers/vhost/vhost.c:454
vhost_task_fn+0x156/0x430 kernel/vhost_task.c:49
ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245