rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5816/1:b..l P3950/2:b..l P13/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=9761, q=1332 ncpus=2)
task:kworker/u8:1 state:R running task stack:21056 pid:13 tgid:13 ppid:2 task_flags:0x24208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x14de/0x5210 kernel/sched/core.c:6907
preempt_schedule_notrace+0x57/0x90 kernel/sched/core.c:7184
preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13
rcu_is_watching+0x7f/0xb0 kernel/rcu/tree.c:753
trace_lock_acquire include/trace/events/lock.h:24 [inline]
lock_acquire+0x5f/0x330 kernel/locking/lockdep.c:5831
rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
rcu_read_lock include/linux/rcupdate.h:850 [inline]
percpu_ref_put_many+0x3e/0x240 include/linux/percpu-refcount.h:330
percpu_ref_put include/linux/percpu-refcount.h:351 [inline]
blk_mq_dispatch_list+0xd3f/0xe20 block/blk-mq.c:2956
blk_mq_flush_plug_list+0x48d/0x570 block/blk-mq.c:3000
__blk_flush_plug+0x3ed/0x4d0 block/blk-core.c:1230
blk_flush_plug include/linux/blkdev.h:1205 [inline]
io_schedule_prepare kernel/sched/core.c:7800 [inline]
io_schedule+0x78/0xe0 kernel/sched/core.c:7830
rq_qos_wait+0x269/0x360 block/blk-rq-qos.c:307
__wbt_wait block/blk-wbt.c:598 [inline]
wbt_wait+0x329/0x590 block/blk-wbt.c:658
__rq_qos_throttle+0x6b/0xb0 block/blk-rq-qos.c:66
rq_qos_throttle block/blk-rq-qos.h:164 [inline]
blk_mq_get_new_requests block/blk-mq.c:3066 [inline]
blk_mq_submit_bio+0x62c/0x2890 block/blk-mq.c:3217
__submit_bio+0x1c0/0x580 block/blk-core.c:635
__submit_bio_noacct_mq block/blk-core.c:722 [inline]
submit_bio_noacct_nocheck+0x2f4/0xa20 block/blk-core.c:753
__block_write_full_folio+0x810/0xe10 fs/buffer.c:1934
blkdev_writepages+0xef/0x1b0 block/fops.c:487
do_writepages+0x32e/0x550 mm/page-writeback.c:2598
__writeback_single_inode+0x133/0x1060 fs/fs-writeback.c:1750
writeback_sb_inodes+0x92e/0x1910 fs/fs-writeback.c:2041
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2118
wb_writeback+0x459/0xad0 fs/fs-writeback.c:2229
wb_check_old_data_flush fs/fs-writeback.c:2333 [inline]
wb_do_writeback fs/fs-writeback.c:2386 [inline]
wb_workfn+0xaf3/0xf00 fs/fs-writeback.c:2414
process_one_work kernel/workqueue.c:3275 [inline]
process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3358
worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
kthread+0x388/0x470 kernel/kthread.c:467
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
task:kworker/u8:9 state:R running task stack:21728 pid:3950 tgid:3950 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: events_unbound nsim_dev_trap_report_work
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x14de/0x5210 kernel/sched/core.c:6907
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7091
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline]
_raw_spin_unlock_irqrestore+0x74/0x80 kernel/locking/spinlock.c:194
unlock_rt_mutex_safe kernel/locking/rtmutex.c:344 [inline]
rt_mutex_slowunlock+0x4a7/0x8b0 kernel/locking/rtmutex.c:1454
spin_unlock include/linux/spinlock_rt.h:109 [inline]
napi_skb_cache_get+0x2e4/0x410 net/core/skbuff.c:296
__alloc_skb+0x1a7/0x390 net/core/skbuff.c:673
alloc_skb include/linux/skbuff.h:1383 [inline]
nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:818 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:875 [inline]
nsim_dev_trap_report_work+0x29f/0xbc0 drivers/net/netdevsim/dev.c:921
process_one_work kernel/workqueue.c:3275 [inline]
process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3358
worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
kthread+0x388/0x470 kernel/kthread.c:467
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
task:udevd state:R running task stack:27032 pid:5816 tgid:5816 ppid:5164 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x14de/0x5210 kernel/sched/core.c:6907
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7234
irqentry_exit+0x599/0x620 kernel/entry/common.c:239
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x221/0x330 kernel/locking/lockdep.c:5872
Code: ff ff ff e8 71 44 73 09 f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 db a1 89 10 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 80 02 77 09 cc 48 8d 3d b8 33 ad
RSP: 0018:ffffc90004e2f878 EFLAGS: 00000286
RAX: 5962926106817f00 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 000000005f479b93 RSI: ffffffff8d5a1617 RDI: ffffffff8b861580
RBP: ffffffff81759245 R08: ffffffff81759245 R09: ffffffff8dbcd480
R10: ffffc90004e2f9d8 R11: ffffffff81ae4380 R12: 0000000000000002
R13: ffffffff8dbcd480 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+0xc2/0x23c0 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 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:2670 [inline]
slab_free mm/slub.c:6082 [inline]
kmem_cache_free+0x185/0x690 mm/slub.c:6212
free_filename fs/namei.c:147 [inline]
putname fs/namei.c:306 [inline]
class_filename_destructor include/linux/fs.h:2539 [inline]
class_filename_flags_destructor include/linux/fs.h:2541 [inline]
user_path_at+0xd4/0x160 fs/namei.c:3613
inotify_find_inode fs/notify/inotify/inotify_user.c:377 [inline]
__do_sys_inotify_add_watch fs/notify/inotify/inotify_user.c:771 [inline]
__se_sys_inotify_add_watch+0x18d/0xf70 fs/notify/inotify/inotify_user.c:729
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f082c55e9a7
RSP: 002b:00007ffe1f79def8 EFLAGS: 00000202 ORIG_RAX: 00000000000000fe
RAX: ffffffffffffffda RBX: 0000563ebd4e1b20 RCX: 00007f082c55e9a7
RDX: 0000000000000008 RSI: 0000563ebd4d0480 RDI: 0000000000000007
RBP: 0000563ebd4cf910 R08: 00000000000001d0 R09: 0000000000000003
R10: 0000000000000000 R11: 0000000000000202 R12: 0000563ebd4e1b20
R13: 0000563ebd4dd190 R14: 0000000000000008 R15: 0000563ebd4e1b20
rcu: rcu_preempt kthread starved for 10502 jiffies! g9761 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:28112 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x14de/0x5210 kernel/sched/core.c:6907
__schedule_loop kernel/sched/core.c:6989 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7004
schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
kthread+0x388/0x470 kernel/kthread.c:467
ret_from_fork+0x51e/0xb90 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 02/12/2026
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
Code: 14 4c 02 e9 53 c2 03 00 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 53 32 17 00 fb f4 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffffff8d807dc0 EFLAGS: 00000246
RAX: 00000000000c20f3 RBX: ffffffff819849cd RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8d34722c RDI: ffffffff8b861580
RBP: ffffffff8d807eb0 R08: ffff8880b8833cdb R09: 1ffff1101710679b
R10: dffffc0000000000 R11: ffffed101710679c R12: ffffffff8f492870
R13: 1ffffffff1b205d8 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888126595000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fffe9dd8c90 CR3: 0000000028da4000 CR4: 00000000003526f0
Call Trace:
arch_safe_halt arch/x86/kernel/process.c:766 [inline]
default_idle+0x9/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x1bd/0x500 kernel/sched/idle.c:332
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:430
rest_init+0x2de/0x300 init/main.c:757
start_kernel+0x380/0x3d0 init/main.c:1206
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