rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6128/1:b..l P4155/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=9689, q=35257 ncpus=2)
task:kworker/u8:15 state:R running task stack:25480 pid:4155 tgid:4155 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: iou_exit io_ring_exit_work
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6863
preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190
irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:56 [inline]
RIP: 0010:stack_access_ok+0x53/0x200 arch/x86/kernel/unwind_orc.c:393
Code: 83 ec 08 80 3c 02 00 0f 85 94 01 00 00 4c 8d 6b 10 4c 8b 7b 08 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 80 3c 02 00 <0f> 85 52 01 00 00 48 89 da 48 8b 4b 10 48 b8 00 00 00 00 00 fc ff
RSP: 0018:ffffc9000e9bf268 EFLAGS: 00000246
RAX: dffffc0000000000 RBX: ffffc9000e9bf318 RCX: ffffffff9125582e
RDX: 1ffff92001d37e65 RSI: ffffc9000e9bf948 RDI: ffffc9000e9bf318
RBP: ffffc9000e9bf948 R08: ffffffff91255832 R09: 000000002aba8118
R10: 0000000000000002 R11: 000000000000a44c R12: 0000000000000008
R13: ffffc9000e9bf328 R14: ffffc9000e9bf320 R15: ffffc9000e9b8000
deref_stack_reg arch/x86/kernel/unwind_orc.c:403 [inline]
unwind_next_frame+0xb7d/0x20a0 arch/x86/kernel/unwind_orc.c:585
arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
kasan_save_track+0x14/0x30 mm/kasan/common.c:77
unpoison_slab_object mm/kasan/common.c:339 [inline]
__kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:365
kasan_slab_alloc include/linux/kasan.h:252 [inline]
slab_post_alloc_hook mm/slub.c:4953 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
kmem_cache_alloc_noprof+0x25e/0x770 mm/slub.c:5270
kmem_alloc_batch+0x49/0x170 lib/debugobjects.c:371
fill_pool lib/debugobjects.c:403 [inline]
debug_objects_fill_pool lib/debugobjects.c:725 [inline]
debug_objects_fill_pool+0x413/0x660 lib/debugobjects.c:697
debug_object_activate+0x10b/0x4c0 lib/debugobjects.c:814
debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline]
__call_rcu_common.constprop.0+0x35/0xa10 kernel/rcu/tree.c:3104
slab_free_hook mm/slub.c:2504 [inline]
slab_free mm/slub.c:6668 [inline]
kmem_cache_free+0x171/0x770 mm/slub.c:6779
__io_req_caches_free+0x19e/0x5c0 io_uring/io_uring.c:2823
io_req_caches_free io_uring/io_uring.c:2835 [inline]
io_ring_exit_work+0x33c/0x1130 io_uring/io_uring.c:3021
process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
task:syz.4.48 state:R running task stack:24952 pid:6128 tgid:6128 ppid:5812 task_flags:0x40004c flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6863
preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190
irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x62/0x330 kernel/locking/lockdep.c:5872
Code: 36 18 12 83 f8 07 0f 87 a2 02 00 00 89 c0 48 0f a3 05 82 83 ee 0e 0f 82 74 02 00 00 8b 35 1a b4 ee 0e 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 99 36 18 12 0f 85 ad 02 00 00 48 83 c4
RSP: 0018:ffffc90005ed7280 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e3c9620 RCX: 000000000d5ca3bf
RDX: 0000000000000000 RSI: ffffffff8daa563c RDI: ffffffff8bf2a580
RBP: 0000000000000002 R08: 000000003e9bd0da R09: 00000000a3e9bd0d
R10: 0000000000000002 R11: ffff88803561d4b0 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:867 [inline]
class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0xd1/0x20a0 arch/x86/kernel/unwind_orc.c:479
arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
kasan_save_track+0x14/0x30 mm/kasan/common.c:77
unpoison_slab_object mm/kasan/common.c:339 [inline]
__kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:365
kasan_slab_alloc include/linux/kasan.h:252 [inline]
slab_post_alloc_hook mm/slub.c:4953 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
kmem_cache_alloc_noprof+0x25e/0x770 mm/slub.c:5270
kmem_alloc_batch+0x49/0x170 lib/debugobjects.c:371
fill_pool lib/debugobjects.c:403 [inline]
debug_objects_fill_pool lib/debugobjects.c:725 [inline]
debug_objects_fill_pool+0x413/0x660 lib/debugobjects.c:697
debug_object_activate+0x10b/0x4c0 lib/debugobjects.c:814
debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline]
__call_rcu_common.constprop.0+0x35/0xa10 kernel/rcu/tree.c:3104
slab_free_hook mm/slub.c:2504 [inline]
slab_free mm/slub.c:6668 [inline]
kmem_cache_free+0x171/0x770 mm/slub.c:6779
anon_vma_free mm/rmap.c:136 [inline]
__put_anon_vma+0x114/0x3a0 mm/rmap.c:2780
put_anon_vma include/linux/rmap.h:117 [inline]
unlink_anon_vmas+0x58a/0x820 mm/rmap.c:443
free_pgtables+0x1d7/0xc10 mm/memory.c:399
exit_mmap+0x3f1/0xb60 mm/mmap.c:1288
__mmput+0x12a/0x410 kernel/fork.c:1173
mmput+0x62/0x70 kernel/fork.c:1196
exit_mm kernel/exit.c:581 [inline]
do_exit+0x7d7/0x2bd0 kernel/exit.c:959
do_group_exit+0xd3/0x2a0 kernel/exit.c:1112
__do_sys_exit_group kernel/exit.c:1123 [inline]
__se_sys_exit_group kernel/exit.c:1121 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1121
x64_sys_call+0x151c/0x1740 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f94e738f749
RSP: 002b:00007ffc4e6efee8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f94e738f749
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffc4e6eff4c R08: 000000124e6effdf R09: 0000555565c0e590
R10: 0000000000000144 R11: 0000000000000246 R12: 0000000000000008
R13: 0000555565c0e590 R14: 00000000000175ab R15: 00007ffc4e6effa0
rcu: rcu_preempt kthread starved for 10496 jiffies! g9689 f0x2 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:27976 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6960
schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 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+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: 36 60 02 c3 cc cc cc cc 0f 1f 00 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 e9 12 00 fb f4 cc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197de8 EFLAGS: 000002c6
RAX: 000000000028362b RBX: 0000000000000001 RCX: ffffffff8b7776d9
RDX: 0000000000000000 RSI: ffffffff8dacb6cd RDI: ffffffff8bf2a580
RBP: ffffed1003b54498 R08: 0000000000000001 R09: ffffed10170a673d
R10: ffff8880b85339eb R11: ffff88801daa2ff0 R12: 0000000000000001
R13: ffff88801daa24c0 R14: ffffffff90887cd0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881249fd000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2fee5ff8 CR3: 0000000075c25000 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+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x38d/0x510 kernel/sched/idle.c:332
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430
start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312
common_startup_64+0x13e/0x148