rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7712/1:b..l P36/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=41941, q=545 ncpus=2)
task:kworker/u8:3 state:R running task stack:22456 pid:36 tgid:36 ppid:2 task_flags:0x4208160 flags:0x00080000
Workqueue: iou_exit io_ring_exit_work
Call Trace:
context_switch kernel/sched/core.c:5282 [inline]
__schedule+0x14ed/0x5040 kernel/sched/core.c:6894
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7221
irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x222/0x340 kernel/locking/lockdep.c:5872
Code: ff ff ff e8 60 8c bf 09 f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 7a 9a 03 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d 97 aa 07
RSP: 0018:ffffc90000ac73b8 EFLAGS: 00000286
RAX: a78ebbe94d5f8f00 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 0000000005fead61 RSI: ffffffff8db84067 RDI: ffffffff8be08ae0
RBP: ffffffff8173fd75 R08: ffffffff8173fd75 R09: ffffffff8e13efa0
R10: ffffc90000ac7518 R11: ffffffff81acb2b0 R12: 0000000000000002
R13: ffffffff8e13efa0 R14: 0000000000000000 R15: 0000000000000246
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+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495
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:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__kmalloc_cache_noprof+0x3e2/0x700 mm/slub.c:5796
kmalloc_noprof include/linux/slab.h:957 [inline]
slab_free_hook mm/slub.c:2508 [inline]
slab_free mm/slub.c:6690 [inline]
kmem_cache_free+0x16b/0x620 mm/slub.c:6801
__io_req_caches_free+0x1c1/0x270 io_uring/io_uring.c:2804
io_req_caches_free+0x21/0x60 io_uring/io_uring.c:2816
io_ring_exit_work+0x3d3/0x940 io_uring/io_uring.c:3002
process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279
process_scheduled_works kernel/workqueue.c:3362 [inline]
worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443
kthread+0x389/0x480 kernel/kthread.c:467
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
task:udevd state:R running task stack:23544 pid:7712 tgid:7712 ppid:5191 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5282 [inline]
__schedule+0x14ed/0x5040 kernel/sched/core.c:6894
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7221
irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__sanitizer_cov_trace_pc+0x5d/0x70 kernel/kcov.c:235
Code: 20 16 00 00 83 fa 02 75 21 48 8b 91 28 16 00 00 48 8b 32 48 8d 7e 01 8b 89 24 16 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 cc cc cc cc cc 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90
RSP: 0018:ffffc9000b9afa58 EFLAGS: 00000293
RAX: ffffffff823df80b RBX: ffffc9000b9afc60 RCX: ffff88802d798000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000b9afc00 R08: ffffffff823dc004 R09: ffffffff8e13efa0
R10: ffffc9000b9afc60 R11: fffff52001735f8e R12: dffffc0000000000
R13: 1ffff92001735f93 R14: ffffc9000b9afc98 R15: 0000000000000000
nd_jump_root+0x7b/0x430 fs/namei.c:1079
path_init+0x434/0x1330 fs/namei.c:2659
path_lookupat+0x2a/0x8c0 fs/namei.c:2742
filename_lookup+0x212/0x570 fs/namei.c:2781
do_readlinkat+0xd9/0x500 fs/stat.c:576
__do_sys_readlink fs/stat.c:613 [inline]
__se_sys_readlink fs/stat.c:610 [inline]
__x64_sys_readlink+0x7f/0x90 fs/stat.c:610
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f20ea3153a7
RSP: 002b:00007ffdee1c56d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000059
RAX: ffffffffffffffda RBX: 00007ffdee1c60b0 RCX: 00007f20ea3153a7
RDX: 0000000000000400 RSI: 00007ffdee1c5b90 RDI: 00007ffdee1c60b0
RBP: 00007ffdee1c60bf R08: 0000000000000075 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000246 R12: 00007ffdee1c5b90
R13: 00007ffdee1c5790 R14: 000055f4326166d7 R15: 000055f4403b62d0
rcu: rcu_preempt kthread starved for 10566 jiffies! g41941 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:27936 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5282 [inline]
__schedule+0x14ed/0x5040 kernel/sched/core.c:6894
__schedule_loop kernel/sched/core.c:6976 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6991
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x11b0 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x9b/0x2d0 kernel/rcu/tree.c:2297
kthread+0x389/0x480 kernel/kthread.c:467
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
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: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(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 43 ce 2a 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:ffffc90000197e20 EFLAGS: 000002c2
RAX: 0000000000ce0779 RBX: ffffffff8197161e RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8d9a0684 RDI: ffffffff8be08ae0
RBP: ffffc90000197f10 R08: ffff8880b873375b R09: 1ffff110170e66eb
R10: dffffc0000000000 R11: ffffed10170e66ec R12: ffffffff8fa25b70
R13: 1ffff11003ad4b58 R14: 0000000000000001 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff888125d07000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2b502d2cec CR3: 000000007d2cc000 CR4: 00000000003526f0
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:191 [inline]
do_idle+0x1be/0x4d0 kernel/sched/idle.c:332
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430
start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
common_startup_64+0x13e/0x147