rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P14523/1:b..l P10064/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=86189, q=330 ncpus=2)
task:syz-executor state:R running task stack:20896 pid:10064 tgid:10064 ppid:10063 task_flags:0x400140 flags:0x00080000
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+0x5e3/0x670 kernel/entry/common.c:216
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x222/0x340 kernel/locking/lockdep.c:5872
Code: ff ff ff e8 20 c1 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 78 e7
RSP: 0018:ffffc9000b88f198 EFLAGS: 00000282
RAX: 32f1ea8870effc00 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 00000000ae70feff RSI: ffffffff8d976155 RDI: ffffffff8bc08360
RBP: ffffffff8173fd65 R08: ffffffff8173fd65 R09: ffffffff8df41aa0
R10: dffffc0000000000 R11: fffff52001711e6d 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
__unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:773
unwind_start arch/x86/include/asm/unwind.h:64 [inline]
arch_stack_walk+0xe4/0x150 arch/x86/kernel/stacktrace.c:24
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
save_stack+0xf5/0x1f0 mm/page_owner.c:165
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1406 [inline]
free_unref_folios+0xdb3/0x14f0 mm/page_alloc.c:3000
folios_put_refs+0x584/0x670 mm/swap.c:1002
folio_batch_release include/linux/pagevec.h:101 [inline]
shmem_undo_range+0x49e/0x1490 mm/shmem.c:1137
shmem_truncate_range mm/shmem.c:1249 [inline]
shmem_evict_inode+0x26e/0xa70 mm/shmem.c:1379
evict+0x5f4/0xae0 fs/inode.c:837
do_unlinkat+0x340/0x560 fs/namei.c:5443
__do_sys_unlink fs/namei.c:5474 [inline]
__se_sys_unlink fs/namei.c:5472 [inline]
__x64_sys_unlink+0x47/0x50 fs/namei.c:5472
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: 0033:0x7f93a5b8ecf7
RSP: 002b:00007ffd73f36be8 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f93a5b8ecf7
RDX: 00007ffd73f36c10 RSI: 00007ffd73f36ca0 RDI: 00007ffd73f36ca0
RBP: 00007ffd73f36ca0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffd73f37d30
R13: 00007f93a5c13d7d R14: 0000000000106e06 R15: 00007ffd73f37d70
task:udevd state:R running task stack:27840 pid:14523 tgid:14523 ppid:5192 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7047
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
_raw_spin_unlock_irqrestore+0x74/0x80 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
__wake_up_common_lock+0x190/0x1f0 kernel/sched/wait.c:127
sock_def_readable+0x1eb/0x530 net/core/sock.c:3611
unix_dgram_sendmsg+0xdfb/0x1840 net/unix/af_unix.c:2286
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg+0x21c/0x270 net/socket.c:742
sock_write_iter+0x279/0x360 net/socket.c:1195
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5c9/0xb30 fs/read_write.c:686
ksys_write+0x145/0x250 fs/read_write.c:738
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: 0033:0x7ff7220a7407
RSP: 002b:00007ffee37e3360 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ff722889880 RCX: 00007ff7220a7407
RDX: 0000000000000000 RSI: 00007ffee37e3407 RDI: 000000000000000a
RBP: 000000000000000a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007ff7228896e8
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000004
rcu: rcu_preempt kthread starved for 10583 jiffies! g86189 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: 0 Comm: swapper/0 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:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:194
Code: f7 e8 cd 4a 42 f6 f7 c3 00 02 00 00 74 05 e8 f0 78 6c f6 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 04 65 34 f6 65 8b 05 0d c8 23 07 85 c0 74 18 5b 41 5e e9 dc f8
RSP: 0018:ffffc90000007aa8 EFLAGS: 00000206
RAX: 0000000000000002 RBX: 0000000000000246 RCX: 0000000080000103
RDX: 0000000000000000 RSI: ffffffff8d792261 RDI: 0000000000000001
RBP: ffffc90000007d90 R08: ffffffff8f822377 R09: 1ffffffff1f0446e
R10: dffffc0000000000 R11: fffffbfff1f0446f R12: dffffc0000000000
R13: 000000000000d000 R14: ffff8880282b4000 R15: ffff888143fa4470
FS: 0000000000000000(0000) GS:ffff888125e1f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f93a5de7dac CR3: 000000000dd3a000 CR4: 0000000000350ef0
Call Trace:
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
dummy_timer+0x447c/0x45b0 drivers/usb/gadget/udc/dummy_hcd.c:-1
__run_hrtimer kernel/time/hrtimer.c:1777 [inline]
__hrtimer_run_queues+0x51c/0xc30 kernel/time/hrtimer.c:1841
hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1858
handle_softirqs+0x22b/0x7c0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x60/0x150 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:sched_core_balance+0x11b/0xe10 kernel/sched/core.c:6284
Code: dd d0 fd 9a 8d 4c 89 f0 48 c1 e8 03 48 89 84 24 b0 00 00 00 42 80 3c 20 00 74 08 4c 89 f7 e8 bc 54 94 00 48 c7 c3 88 c4 81 92 <49> 03 1e 48 89 d8 48 c1 e8 03 42 80 3c 20 00 4c 8b 7c 24 08 74 08
RSP: 0018:ffffffff8dc07a98 EFLAGS: 00000246
RAX: 1ffffffff1b35fba RBX: ffffffff9281c488 RCX: 0000000080000002
RDX: 0000000000000000 RSI: ffffffff8d792261 RDI: ffffffff8bc08360
RBP: ffffffff8dc07db0 R08: ffffffff8f822377 R09: 1ffffffff1f0446e
R10: dffffc0000000000 R11: fffffbfff1f0446f R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff8d9afdd0 R15: 0000000000000000
do_balance_callbacks kernel/sched/core.c:4901 [inline]
__balance_callbacks+0x110/0x190 kernel/sched/core.c:4955
__schedule+0x199e/0x4fd0 kernel/sched/core.c:6870
schedule_idle+0x52/0x90 kernel/sched/core.c:6986
do_idle+0x472/0x4d0 kernel/sched/idle.c:360
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430
rest_init+0x2de/0x300 init/main.c:757
start_kernel+0x381/0x3d0 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