rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P21037/1:b..l
rcu: (detected by 0, t=10503 jiffies, g=198157, q=216 ncpus=2)
task:kworker/u8:32 state:R running task stack:22264 pid:21037 tgid:21037 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: kvfree_rcu_reclaim kfree_rcu_work
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7190
irqentry_exit+0x5d8/0x660 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 00 a1 bb 09 f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 0a 20 e2 10 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 da 50 72 ff cc 48 8d 3d 37 77 e7
RSP: 0018:ffffc90003ce7338 EFLAGS: 00000282
RAX: 8196c0f382a21400 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 0000000056b46fc0 RSI: ffffffff8d975f94 RDI: ffffffff8bc083e0
RBP: ffffffff8173fd65 R08: ffffffff8173fd65 R09: ffffffff8df41aa0
R10: dffffc0000000000 R11: ffffffff81acf3d0 R12: 0000000000000002
R13: ffffffff8df41aa0 R14: 0000000000000000 R15: 0000000000000246
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+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
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2540 [inline]
slab_free_freelist_hook mm/slub.c:2569 [inline]
slab_free_bulk mm/slub.c:6703 [inline]
kmem_cache_free_bulk+0x3fb/0xdb0 mm/slub.c:7390
kfree_bulk include/linux/slab.h:830 [inline]
kvfree_rcu_bulk+0xe5/0x1f0 mm/slab_common.c:1523
kfree_rcu_work+0xed/0x170 mm/slab_common.c:1601
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
kthread+0x711/0x8a0 kernel/kthread.c:463
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: rcu_preempt kthread starved for 10451 jiffies! g198157 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:27480 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
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+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:
CPU: 0 UID: 0 PID: 27435 Comm: syz.4.5422 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:debug_lockdep_rcu_enabled+0x0/0x40 kernel/rcu/update.c:319
Code: 48 8d 3d 83 d7 2b 04 48 c7 c6 6d f7 77 8d 67 48 0f b9 3a 90 eb ca cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 31 c0 83 3d 07 8d 28 04 00 74 1e 83 3d 1a bc 28 04 00
RSP: 0018:ffffc9000d397888 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 0000000000000000 RSI: ffffffff8d975f94 RDI: ffffffff8bc083e0
RBP: 00000000000000b5 R08: ffff888059649e87 R09: 1ffff1100b2c93d0
R10: dffffc0000000000 R11: ffffed100b2c93d1 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff8d7b97d9 R15: 0000000000000000
FS: 00007f4c87a766c0(0000) GS:ffff888125e1f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fffdd863e00 CR3: 0000000065df2000 CR4: 0000000000350ef0
Call Trace:
__might_resched+0x71/0x4d0 kernel/sched/core.c:8789
__might_fault+0x77/0x130 mm/memory.c:7172
__clear_user arch/x86/include/asm/uaccess_64.h:181 [inline]
copy_fpstate_to_sigframe+0x13a/0xcc0 arch/x86/kernel/fpu/signal.c:203
get_sigframe+0x58d/0x7d0 arch/x86/kernel/signal.c:163
x64_setup_rt_frame+0x15b/0xd40 arch/x86/kernel/signal_64.c:175
setup_rt_frame arch/x86/kernel/signal.c:250 [inline]
handle_signal arch/x86/kernel/signal.c:294 [inline]
arch_do_signal_or_restart+0x3d1/0x7a0 arch/x86/kernel/signal.c:339
__exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
exit_to_user_mode_loop+0x87/0x4e0 kernel/entry/common.c:75
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4c86b8f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4c87a760e8 EFLAGS: 00000246
RAX: fffffffffffffffc RBX: 00007f4c86de5fa8 RCX: 00007f4c86b8f749
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f4c86de5fa8
RBP: 00007f4c86de5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4c86de6038 R14: 00007ffcefbc6c60 R15: 00007ffcefbc6d48