rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4196/1:b..l
(detected by 1, t=10502 jiffies, g=15369, q=116)
task:syz-executor state:R running task stack:21536 pid: 4196 ppid: 4181 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6799
irqentry_exit+0x63/0x70 kernel/entry/common.c:432
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:xa_is_internal include/linux/xarray.h:170 [inline]
RIP: 0010:xa_is_node include/linux/xarray.h:1241 [inline]
RIP: 0010:xas_find+0x640/0xab0 lib/xarray.c:1267
Code: 4c 8b 74 24 10 0f 85 54 02 00 00 41 c6 45 00 00 48 85 ed 0f 84 43 03 00 00 e8 0c db 77 fd e9 66 fe ff ff 41 83 fe 02 0f 94 c0 <48> 81 fd fe 00 00 00 0f 92 c1 48 85 ed 74 08 20 c1 0f 84 22 03 00
RSP: 0018:ffffc90002f4f6a8 EFLAGS: 00000293
RAX: ffffffff83ffef00 RBX: dffffc0000000000 RCX: ffff88807bfd9d01
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffffea00013de0c0 R08: ffff88807bfd9dc0 R09: 0000000000000002
R10: 0000000000000003 R11: 0000000000000000 R12: 1ffff920005e9ef6
R13: ffffc90002f4f7b2 R14: 0000000000000000 R15: ffffc90002f4f7b8
find_get_entry mm/filemap.c:1978 [inline]
find_lock_entries+0x188/0xd50 mm/filemap.c:2092
shmem_undo_range+0x23a/0x1880 mm/shmem.c:943
shmem_truncate_range mm/shmem.c:1063 [inline]
shmem_evict_inode+0x20d/0xa00 mm/shmem.c:1145
evict+0x485/0x870 fs/inode.c:647
__dentry_kill+0x431/0x650 fs/dcache.c:586
dentry_kill+0xb8/0x290 fs/dcache.c:-1
dput+0xd8/0x1a0 fs/dcache.c:893
__fput+0x5ee/0x930 fs/file_table.c:319
task_work_run+0x125/0x1a0 kernel/task_work.c:188
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f4ac6727ed7
RSP: 002b:00007ffc906963d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f4ac67a9c05 RCX: 00007f4ac6727ed7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc90696490
RBP: 00007ffc90696490 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffc90697520
R13: 00007f4ac67a9c05 R14: 0000000000024e00 R15: 00007ffc90697560
rcu: rcu_preempt kthread starved for 10533 jiffies! g15369 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:28032 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 5665 Comm: syz.3.215 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592
check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
rcu_pending kernel/rcu/tree.c:3936 [inline]
rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619
update_process_times+0x193/0x200 kernel/time/timer.c:1818
tick_sched_handle kernel/time/tick-sched.c:254 [inline]
tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
__run_hrtimer kernel/time/hrtimer.c:1690 [inline]
__hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1754
hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
__sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:should_resched arch/x86/include/asm/preempt.h:103 [inline]
RIP: 0010:__local_bh_enable_ip+0x132/0x1b0 kernel/softirq.c:408
Code: 8a e8 52 8c 60 08 65 66 8b 05 ca 25 bb 7e 66 85 c0 75 54 bf 01 00 00 00 e8 9b fe 08 00 e8 06 76 35 00 fb 65 8b 05 76 fc b9 7e <85> c0 75 05 e8 25 07 b8 ff 48 c7 04 24 0e 36 e0 45 4b c7 04 37 00
RSP: 0018:ffffc90003e0fa80 EFLAGS: 00000282
RAX: 0000000080000000 RBX: 0000000000000200 RCX: 673fbc8fa2dc2a00
RDX: dffffc0000000000 RSI: ffffffff8a0b1820 RDI: ffffffff8a59a480
RBP: ffffc90003e0fb10 R08: dffffc0000000000 R09: ffffed1027fd4641
R10: ffffed1027fd4641 R11: 1ffff11027fd4640 R12: ffffffff812bddd5
R13: 1ffff1100f7e4e19 R14: dffffc0000000000 R15: 1ffff920007c1f50
fpregs_unlock arch/x86/include/asm/fpu/api.h:78 [inline]
copy_fpstate_to_sigframe+0x7f8/0xb90 arch/x86/kernel/fpu/signal.c:205
get_sigframe arch/x86/kernel/signal.c:295 [inline]
__setup_rt_frame arch/x86/kernel/signal.c:471 [inline]
setup_rt_frame arch/x86/kernel/signal.c:780 [inline]
handle_signal arch/x86/kernel/signal.c:824 [inline]
arch_do_signal_or_restart+0x67a/0x1300 arch/x86/kernel/signal.c:869
handle_signal_work kernel/entry/common.c:154 [inline]
exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f15796fdba9
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:00007fffc95e5db8 EFLAGS: 00000246
RAX: fffffffffffffffc RBX: 000000000002608e RCX: 00007f15796fdba9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f1579944fac
RBP: 0000000000000fd2 R08: 002e91cd586d30a8 R09: 00000019c95e60af
R10: 00007fffc95e5eb0 R11: 0000000000000246 R12: 00007f1579944fac
R13: 00007fffc95e5eb0 R14: 0000000000027060 R15: 00007fffc95e5ed0