rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8466/2:b..l P8470/1:b..l
rcu: (detected by 0, t=10503 jiffies, g=25217, q=324 ncpus=2)
task:syz.0.627 state:R running task stack:27576 pid:8470 tgid:8467 ppid:5813 task_flags:0x400140 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_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x62/0x330 kernel/locking/lockdep.c:5872
Code: a6 18 12 83 f8 07 0f 87 a2 02 00 00 89 c0 48 0f a3 05 82 b5 ee 0e 0f 82 74 02 00 00 8b 35 1a e6 ee 0e 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 99 a6 18 12 0f 85 ad 02 00 00 48 83 c4
RSP: 0018:ffffc900054e7050 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e3c9620 RCX: 00000000eb4cc0aa
RDX: 0000000000000000 RSI: ffffffff8daa7ab3 RDI: ffffffff8bf2b300
RBP: 0000000000000002 R08: 000000000ce2df6b R09: 00000000b0ce2df6
R10: 0000000000000002 R11: ffff888022bf0b30 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_lru_noprof+0x262/0x770 mm/slub.c:5282
__d_alloc+0x35/0xa80 fs/dcache.c:1730
d_alloc+0x4a/0x1e0 fs/dcache.c:1809
lookup_one_qstr_excl+0x175/0x250 fs/namei.c:1743
__start_dirop fs/namei.c:2866 [inline]
start_dirop+0x59/0xb0 fs/namei.c:2875
simple_start_creating+0xf4/0x100 fs/libfs.c:2338
debugfs_start_creating.part.0+0x86/0x1c0 fs/debugfs/inode.c:394
debugfs_start_creating fs/debugfs/inode.c:371 [inline]
debugfs_create_symlink+0x7f/0x260 fs/debugfs/inode.c:672
ref_tracker_dir_symlink+0x255/0x3c0 lib/ref_tracker.c:482
net_ns_net_debugfs net/core/net_namespace.c:810 [inline]
net_ns_net_init+0xd2/0x120 net/core/net_namespace.c:830
ops_init+0x1e2/0x5f0 net/core/net_namespace.c:137
setup_net+0x11d/0x3a0 net/core/net_namespace.c:446
copy_net_ns+0x351/0x7c0 net/core/net_namespace.c:581
create_new_namespaces+0x3ea/0xab0 kernel/nsproxy.c:130
copy_namespaces+0x468/0x570 kernel/nsproxy.c:195
copy_process+0x2a70/0x7430 kernel/fork.c:2224
kernel_clone+0xfc/0x910 kernel/fork.c:2651
__do_sys_clone+0xce/0x120 kernel/fork.c:2792
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: 0033:0x7f461698f749
RSP: 002b:00007f46178b4fe8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007f4616be5fa0 RCX: 00007f461698f749
RDX: 00002000000003c0 RSI: 0000200000000380 RDI: 0000000040000000
RBP: 00007f4616a13f91 R08: 0000200000000440 R09: 0000200000000440
R10: 0000200000000400 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f4616be6038 R14: 00007f4616be5fa0 R15: 00007ffe8ae62408
task:syz.3.623 state:R running task stack:25032 pid:8466 tgid:8452 ppid:5814 task_flags:0x400040 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: a6 18 12 83 f8 07 0f 87 a2 02 00 00 89 c0 48 0f a3 05 82 b5 ee 0e 0f 82 74 02 00 00 8b 35 1a e6 ee 0e 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 99 a6 18 12 0f 85 ad 02 00 00 48 83 c4
RSP: 0018:ffffc90005557650 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e3c9620 RCX: 00000000b8ec8623
RDX: 0000000000000000 RSI: ffffffff8daa7ab3 RDI: ffffffff8bf2b300
RBP: 0000000000000002 R08: 0000000035e43d3a R09: 00000000a35e43d3
R10: 0000000000000002 R11: ffff888026a12ff0 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]
filemap_map_pages+0x193/0x1e00 mm/filemap.c:3881
do_fault_around mm/memory.c:5713 [inline]
do_read_fault mm/memory.c:5746 [inline]
do_fault+0x9cd/0x1ad0 mm/memory.c:5889
do_pte_missing mm/memory.c:4401 [inline]
handle_pte_fault mm/memory.c:6273 [inline]
__handle_mm_fault+0x1919/0x2bb0 mm/memory.c:6411
handle_mm_fault+0x3fe/0xad0 mm/memory.c:6580
faultin_page mm/gup.c:1126 [inline]
__get_user_pages+0x54e/0x3590 mm/gup.c:1428
populate_vma_page_range+0x267/0x3f0 mm/gup.c:1860
__mm_populate+0x1d8/0x380 mm/gup.c:1963
mm_populate include/linux/mm.h:3701 [inline]
vm_mmap_pgoff+0x37f/0x470 mm/util.c:586
ksys_mmap_pgoff+0x7d/0x5c0 mm/mmap.c:604
__do_sys_mmap arch/x86/kernel/sys_x86_64.c:89 [inline]
__se_sys_mmap arch/x86/kernel/sys_x86_64.c:82 [inline]
__x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:82
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: 0033:0x7f5f1cf8f749
RSP: 002b:00007f5f1dd9c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f5f1d1e6180 RCX: 00007f5f1cf8f749
RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007f5f1d013f91 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5f1d1e6218 R14: 00007f5f1d1e6180 R15: 00007fff2d99f078
rcu: rcu_preempt kthread starved for 10588 jiffies! g25217 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:28064 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: 8472 Comm: syz.4.628 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:rt_mutex_owner include/linux/rtmutex.h:52 [inline]
RIP: 0010:rtmutex_spin_on_owner kernel/locking/rtmutex.c:1490 [inline]
RIP: 0010:rt_mutex_slowlock_block.constprop.0+0x4a5/0x830 kernel/locking/rtmutex.c:1645
Code: 00 00 48 8b 06 a8 10 0f 85 d4 fe ff ff 4c 89 f0 48 c1 e8 03 80 3c 18 00 0f 85 eb 01 00 00 4c 3b 65 48 0f 85 b9 fe ff ff f3 90 <4c> 89 c0 48 c1 e8 03 80 3c 18 00 0f 85 03 02 00 00 48 8b 45 50 48
RSP: 0018:ffffc900056679f8 EFLAGS: 00000246
RAX: 1ffff1100e94bc2b RBX: dffffc0000000000 RCX: ffffed10052a3498
RDX: ffff88807c570034 RSI: ffff88802951a4c0 RDI: 0000000000000000
RBP: ffff888074a5e110 R08: ffff888074a5e160 R09: 0000000000000000
R10: 0000000000000002 R11: ffff88802951aff0 R12: ffffc90005667bd0
R13: 0000000000000000 R14: ffff888074a5e158 R15: ffff88807c570000
FS: 00007f8ee8e646c0(0000) GS:ffff8881249f6000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000040 CR3: 0000000045bce000 CR4: 00000000003526f0
Call Trace:
rt_mutex_wait_proxy_lock+0x8f/0x140 kernel/locking/rtmutex_api.c:404
futex_lock_pi+0x3f5/0x7c0 kernel/futex/pi.c:1046
do_futex+0x11a/0x350 kernel/futex/syscalls.c:146
__do_sys_futex kernel/futex/syscalls.c:207 [inline]
__se_sys_futex kernel/futex/syscalls.c:188 [inline]
__x64_sys_futex+0x1e0/0x4c0 kernel/futex/syscalls.c:188
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: 0033:0x7f8ee7f8f749
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:00007f8ee8e64038 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007f8ee81e5fa0 RCX: 00007f8ee7f8f749
RDX: 0000000000000000 RSI: 000000000000000d RDI: 000020000000cffc
RBP: 00007f8ee8013f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8ee81e6038 R14: 00007f8ee81e5fa0 R15: 00007fffda3f1978