rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8738/1:b..l P5197/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=44737, q=693 ncpus=2)
task:udevd state:R running task stack:23288 pid:5197 tgid:5197 ppid:1 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5257 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6864
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7191
irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline]
RIP: 0010:lock_acquire+0x58/0x340 kernel/locking/lockdep.c:5831
Code: 8b 05 ac 98 de 10 48 89 44 24 58 0f 1f 44 00 00 65 8b 05 af 98 de 10 83 f8 08 0f 83 af 01 00 00 89 c0 48 0f a3 05 d8 bb e2 0d <73> 0d e8 d1 24 09 00 84 c0 0f 84 d7 01 00 00 83 3d f2 eb e2 0d 00
RSP: 0018:ffffc90003147458 EFLAGS: 00000297
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8df419e0
RBP: ffffffff81743f85 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc90003147618 R11: ffffffff81ada230 R12: 0000000000000002
R13: ffffffff8df419e0 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+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
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:56 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:252 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284
kasan_slab_free include/linux/kasan.h:234 [inline]
slab_free_hook mm/slub.c:2540 [inline]
slab_free mm/slub.c:6663 [inline]
kfree+0x1c0/0x660 mm/slub.c:6871
tomoyo_path_perm+0x3a2/0x4b0 security/tomoyo/file.c:842
security_inode_getattr+0x12f/0x330 security/security.c:1869
vfs_getattr fs/stat.c:259 [inline]
vfs_statx_path fs/stat.c:299 [inline]
vfs_statx+0x18e/0x550 fs/stat.c:356
vfs_fstatat+0x118/0x170 fs/stat.c:375
__do_sys_newfstatat fs/stat.c:542 [inline]
__se_sys_newfstatat fs/stat.c:536 [inline]
__x64_sys_newfstatat+0x116/0x190 fs/stat.c:536
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7856711b0a
RSP: 002b:00007ffefe028488 EFLAGS: 00000246 ORIG_RAX: 0000000000000106
RAX: ffffffffffffffda RBX: 0000563e90287418 RCX: 00007f7856711b0a
RDX: 00007ffefe028490 RSI: 0000563e90275ef3 RDI: 00000000ffffff9c
RBP: 0000563eaf510148 R08: 000644bec6d8b229 R09: 3fffffffffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffefe028490 R14: 0000000000000000 R15: 000644bec6d8b229
task:udevd state:R running task stack:25336 pid:8738 tgid:8738 ppid:5197 task_flags:0x20440140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5257 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6864
preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7048
preempt_schedule+0xae/0xc0 kernel/sched/core.c:7072
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
_raw_spin_unlock_irq+0x45/0x50 kernel/locking/spinlock.c:202
spin_unlock_irq include/linux/spinlock.h:401 [inline]
loop_queue_work drivers/block/loop.c:865 [inline]
loop_queue_rq+0x9f8/0xb00 drivers/block/loop.c:1891
__blk_mq_issue_directly block/blk-mq.c:2714 [inline]
blk_mq_request_issue_directly+0x3c1/0x710 block/blk-mq.c:2801
blk_mq_issue_direct+0x2a0/0x660 block/blk-mq.c:2822
blk_mq_dispatch_queue_requests+0x6fe/0x800 block/blk-mq.c:2897
blk_mq_flush_plug_list+0x432/0x550 block/blk-mq.c:2980
__blk_flush_plug+0x3d3/0x4b0 block/blk-core.c:1225
blk_finish_plug+0x5e/0x90 block/blk-core.c:1252
read_pages+0x3b2/0x580 mm/readahead.c:176
page_cache_ra_unbounded+0x750/0x990 mm/readahead.c:302
do_page_cache_ra mm/readahead.c:332 [inline]
force_page_cache_ra mm/readahead.c:361 [inline]
page_cache_sync_ra+0x433/0xc40 mm/readahead.c:579
filemap_get_pages+0x468/0x1dc0 mm/filemap.c:2690
filemap_read+0x3f6/0x11a0 mm/filemap.c:2800
blkdev_read_iter+0x30a/0x440 block/fops.c:860
new_sync_read fs/read_write.c:491 [inline]
vfs_read+0x55a/0xa30 fs/read_write.c:572
ksys_read+0x145/0x250 fs/read_write.c:715
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f78566a7407
RSP: 002b:00007ffefe022e80 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f7856d5e880 RCX: 00007f78566a7407
RDX: 0000000000000200 RSI: 00007f7856d56000 RDI: 0000000000000009
RBP: 0000563eaf50b050 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 0000000000020000 R14: 0000563eaf512e18 R15: 00007f7856e2339c
rcu: rcu_preempt kthread starved for 10572 jiffies! g44737 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:27136 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5257 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6864
__schedule_loop kernel/sched/core.c:6946 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6961
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+0x599/0xb30 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full)
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: 93 ef 02 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 73 f0 0e 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:ffffffff8dc07d80 EFLAGS: 000002c6
RAX: b27d1416dc3a1a00 RBX: ffffffff8197913a RCX: b27d1416dc3a1a00
RDX: 0000000000000001 RSI: ffffffff8d783537 RDI: ffffffff8bc018e0
RBP: ffffffff8dc07ea8 R08: ffff8880b86336db R09: 1ffff110170c66db
R10: dffffc0000000000 R11: ffffed10170c66dc R12: ffffffff8f813370
R13: 1ffffffff1b92a68 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125e4f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c356c5f CR3: 000000007620c000 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+0x1ea/0x520 kernel/sched/idle.c:332
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430
rest_init+0x2de/0x300 init/main.c:757
start_kernel+0x3a7/0x400 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