rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P20758/1:b..l P19569/1:b..l P19564/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=145977, q=2926 ncpus=2)
task:udevd state:R running task stack:25624 pid:19564 tgid:19564 ppid:5194 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5282 [inline]
__schedule+0x14db/0x5030 kernel/sched/core.c:6894
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7221
irqentry_exit+0x5e3/0x670 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 c6 c0 09 f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 1a 34 04 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 ff a3 c3 09 cc 48 8d 3d d7 c3 07
RSP: 0018:ffffc900032f77b8 EFLAGS: 00000286
RAX: ea4b308c32577100 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 000000005a44979c RSI: ffffffff8db8dbf6 RDI: ffffffff8be09d60
RBP: ffffffff81745df5 R08: ffffffff81745df5 R09: ffffffff8e144f60
R10: ffffc900032f7918 R11: ffffffff81ad18d0 R12: 0000000000000002
R13: ffffffff8e144f60 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+0xc2/0x23d0 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
unpoison_slab_object mm/kasan/common.c:340 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4969 [inline]
slab_alloc_node mm/slub.c:5283 [inline]
kmem_cache_alloc_noprof+0x37d/0x710 mm/slub.c:5290
alloc_filename fs/namei.c:142 [inline]
do_getname+0x2e/0x250 fs/namei.c:182
getname include/linux/fs.h:2512 [inline]
getname_maybe_null include/linux/fs.h:2519 [inline]
class_filename_maybe_null_constructor include/linux/fs.h:2543 [inline]
vfs_fstatat+0x45/0x170 fs/stat.c:368
__do_sys_newfstatat fs/stat.c:538 [inline]
__se_sys_newfstatat fs/stat.c:532 [inline]
__x64_sys_newfstatat+0x116/0x190 fs/stat.c:532
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: 0033:0x7f7f01311b0a
RSP: 002b:00007ffff213ed18 EFLAGS: 00000246 ORIG_RAX: 0000000000000106
RAX: ffffffffffffffda RBX: 000000000000000e RCX: 00007f7f01311b0a
RDX: 00007ffff213ed20 RSI: 00007ffff213edf0 RDI: 00000000ffffff9c
RBP: 00007ffff213fe30 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffff2140250
R13: 0000000000000000 R14: 000055eb1cefb100 R15: 000055eb1cefb140
task:udevd state:R running task stack:23744 pid:19569 tgid:19569 ppid:5194 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5282 [inline]
__schedule+0x14db/0x5030 kernel/sched/core.c:6894
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7221
irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:unwind_next_frame+0x10e/0x23d0 include/linux/rcupdate.h:-1
Code: 69 18 0e 00 75 1f c6 05 8f 69 18 0e 01 48 c7 c7 00 a1 88 8b be 54 03 00 00 48 c7 c2 40 a1 88 8b e8 b7 45 2a 00 4c 89 6c 24 78 <48> 89 5c 24 70 4d 8d 6e 50 4c 89 e8 48 c1 e8 03 48 89 44 24 38 80
RSP: 0018:ffffc90004a7f338 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffffff8238e915 RCX: 0000000080000001
RDX: 000000005a44979c RSI: ffffffff8be09d40 RDI: ffffffff8be09d00
RBP: dffffc0000000000 R08: ffffffff81745df5 R09: ffffffff8e144f60
R10: ffffc90004a7f458 R11: ffffffff81ad18d0 R12: 1ffff9200094fe81
R13: ffffc90004a7f440 R14: ffffc90004a7f408 R15: ffffffff81745df5
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:2556 [inline]
slab_free mm/slub.c:6690 [inline]
kmem_cache_free+0x197/0x620 mm/slub.c:6801
file_free+0x24/0x1e0 fs/file_table.c:71
__fput_deferred+0x227/0x390 fs/file_table.c:523
fput_close+0x113/0x220 fs/file_table.c:585
path_openat+0x30fe/0x3840 fs/namei.c:4837
do_file_open+0x203/0x440 fs/namei.c:4857
do_sys_openat2+0x105/0x1e0 fs/open.c:1366
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1383
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: 0033:0x7f7f012a7407
RSP: 002b:00007ffff213c0d0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f7f01a63880 RCX: 00007f7f012a7407
RDX: 0000000000080000 RSI: 00007ffff213c240 RDI: ffffffffffffff9c
RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000055eb1cee07f5
R13: 000055eb1cee07f5 R14: 0000000000000001 R15: 000055eb1cefb140
task:syz.4.3212 state:R running task stack:27032 pid:20758 tgid:20730 ppid:19855 task_flags:0x40044c flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5282 [inline]
__schedule+0x14db/0x5030 kernel/sched/core.c:6894
preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7078
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline]
_raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:392 [inline]
zap_pte_range mm/memory.c:1884 [inline]
zap_pmd_range mm/memory.c:1946 [inline]
zap_pud_range mm/memory.c:1975 [inline]
zap_p4d_range mm/memory.c:1996 [inline]
unmap_page_range+0x3c17/0x44e0 mm/memory.c:2017
unmap_single_vma mm/memory.c:2059 [inline]
unmap_vmas+0x399/0x580 mm/memory.c:2101
exit_mmap+0x239/0xb10 mm/mmap.c:1277
__mmput+0x118/0x430 kernel/fork.c:1177
exit_mm+0x169/0x230 kernel/exit.c:581
do_exit+0x81f/0x2590 kernel/exit.c:959
do_group_exit+0x21c/0x2d0 kernel/exit.c:1112
get_signal+0x1285/0x1340 kernel/signal.c:3034
arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
__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+0x2c1/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9842f8f749
RSP: 002b:00007f98411b40e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f98431e6188 RCX: 00007f9842f8f749
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f98431e6188
RBP: 00007f98431e6180 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f98431e6218 R14: 00007ffd8d9e9620 R15: 00007ffd8d9e9708
rcu: rcu_preempt kthread starved for 10396 jiffies! g145977 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:27680 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5282 [inline]
__schedule+0x14db/0x5030 kernel/sched/core.c:6894
__schedule_loop kernel/sched/core.c:6976 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6991
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x11b0 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x9b/0x2d0 kernel/rcu/tree.c:2297
kthread+0x389/0x480 kernel/kthread.c:467
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:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 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:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: cc cc cc cc 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 e3 3f 29 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000197e20 EFLAGS: 000002c2
RAX: 00000000023d44f9 RBX: ffffffff81977eae RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8d9a99b4 RDI: ffffffff8be09d60
RBP: ffffc90000197f10 R08: ffff8880b873375b R09: 1ffff110170e66eb
R10: dffffc0000000000 R11: ffffed10170e66ec R12: ffffffff8fa2d8f0
R13: 1ffff11003adab58 R14: 0000000000000001 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff888125cf7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f190215de63 CR3: 0000000033278000 CR4: 00000000003526f0
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x1be/0x4d0 kernel/sched/idle.c:332
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430
start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
common_startup_64+0x13e/0x147