rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4174/1:b..l
(detected by 1, t=10502 jiffies, g=10933, q=12)
task:udevd state:R running task stack:24752 pid: 4174 ppid: 3561 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571
preempt_schedule+0xbc/0xd0 kernel/sched/core.c:6596
preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
_raw_spin_unlock_irq+0x3c/0x40 kernel/locking/spinlock.c:202
spin_unlock_irq include/linux/spinlock.h:414 [inline]
loop_queue_work drivers/block/loop.c:1069 [inline]
loop_queue_rq+0x9e0/0xac0 drivers/block/loop.c:2202
__blk_mq_issue_directly block/blk-mq.c:2015 [inline]
__blk_mq_try_issue_directly+0x497/0x820 block/blk-mq.c:2071
blk_mq_request_issue_directly block/blk-mq.c:2119 [inline]
blk_mq_try_issue_list_directly+0x1a1/0x530 block/blk-mq.c:2137
blk_mq_sched_insert_requests+0x2d6/0x5c0 block/blk-mq-sched.c:512
blk_mq_flush_plug_list+0x59b/0x690 block/blk-mq.c:1972
blk_flush_plug_list+0x404/0x450 block/blk-core.c:1734
blk_finish_plug+0x59/0x80 block/blk-core.c:1751
read_pages+0x4d2/0x930 mm/readahead.c:150
page_cache_ra_unbounded+0x838/0x940 mm/readahead.c:239
do_page_cache_ra mm/readahead.c:269 [inline]
force_page_cache_ra+0x3e5/0x440 mm/readahead.c:301
page_cache_sync_readahead include/linux/pagemap.h:833 [inline]
filemap_get_pages mm/filemap.c:2551 [inline]
filemap_read+0x5de/0x2540 mm/filemap.c:2634
blkdev_read_iter+0x11d/0x150 block/fops.c:563
call_read_iter include/linux/fs.h:2167 [inline]
new_sync_read fs/read_write.c:404 [inline]
vfs_read+0x759/0xd60 fs/read_write.c:485
ksys_read+0x152/0x260 fs/read_write.c:623
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f9f5c6e0407
RSP: 002b:00007fff4b673b40 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f9f5c5f2880 RCX: 00007f9f5c6e0407
RDX: 0000000000000200 RSI: 00007f9f5bc91000 RDI: 0000000000000009
RBP: 00005579d4343f80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00000000001ce200 R14: 00005579d433c508 R15: 00007f9f5ce3639c
rcu: rcu_preempt kthread starved for 10533 jiffies! g10933 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:28016 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972
rcu_gp_kthread+0x9b/0x370 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:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4780 Comm: syz.0.104 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:hlock_class kernel/locking/lockdep.c:192 [inline]
RIP: 0010:__lock_acquire+0x108e/0x7d10 kernel/locking/lockdep.c:5008
Code: 2d 0c 00 4c 8b 7c 24 18 0f 85 f9 02 00 00 48 83 7c 24 70 00 0f 84 34 02 00 00 48 8b 44 24 78 48 8d 58 f8 48 89 d8 48 c1 e8 03 <42> 0f b6 04 00 84 c0 0f 85 d8 5d 00 00 8b 03 89 c3 81 e3 ff 1f 00
RSP: 0018:ffffc900000079e0 EFLAGS: 00000806
RAX: 1ffff110041158d2 RBX: ffff8880208ac690 RCX: 0000000007403105
RDX: 000000001f689cd2 RSI: 00000000f5d3bf36 RDI: ffffffff901d40c8
RBP: ffffc90000007c30 R08: dffffc0000000000 R09: 1ffffffff203a819
R10: dffffc0000000000 R11: fffffbfff203a81a R12: 00000000b0bbaf2c
R13: ffff8880208abb80 R14: 0000000095aa6107 R15: ffff8880208ac6b8
FS: 00005555716b6500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 0000000052d85000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
seqcount_lockdep_reader_access+0xcd/0x1d0 include/linux/seqlock.h:103
ktime_get_update_offsets_now+0x44/0x3e0 kernel/time/timekeeping.c:2300
hrtimer_update_base kernel/time/hrtimer.c:621 [inline]
hrtimer_interrupt+0x130/0x8d0 kernel/time/hrtimer.c:1793
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:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: 00 00 00 66 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 be a9 97 f7 48 89 df e8 f6 81 98 f7 e8 61 74 b9 f7 fb bf 01 00 00 00 a6 89 8c f7 65 8b 05 47 97 3c 76 85 c0 74 02 5b c3 e8 94 a4 3a
RSP: 0018:ffffc9000459fbc0 EFLAGS: 00000282
RAX: 1b1de81ee4203400 RBX: ffff88805f6eef00 RCX: 1b1de81ee4203400
RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: 0000000000000001
RBP: 0000000000000000 R08: ffff88805f6eef03 R09: 1ffff1100beddde0
R10: dffffc0000000000 R11: ffffed100beddde1 R12: ffff88805f6eef00
R13: 0000000000000021 R14: dffffc0000000000 R15: 000000001c000004
spin_unlock_irq include/linux/spinlock.h:414 [inline]
get_signal+0x11d6/0x12c0 kernel/signal.c:2903
arch_do_signal_or_restart+0xe7/0x12c0 arch/x86/kernel/signal.c:867
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: 0033:0x7fe4785a05b7
Code: 24 08 64 48 2b 14 25 28 00 00 00 75 05 48 83 c4 18 c3 e8 7c 97 00 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 8b 05 a9 00 25 00 <48> 85 c0 74 14 48 83 ec 08 ff d0 85 c0 75 1a 31 c0 48 83 c4 08 c3
RSP: 002b:00007ffdc23fe1d8 EFLAGS: 00000246
RAX: 00007ffdc25d8910 RBX: 0000000000017372 RCX: ffffffffffffffe8
RDX: 0000000000000000 RSI: 00007ffdc23fe300 RDI: 0000000000000001
RBP: 0000000000000032 R08: 00051fd60100f114 R09: 0000000000000000
R10: 00007ffdc23fe2e0 R11: 0000000000000246 R12: 00007ffdc23fe300
R13: 00007fe478820fac R14: 00000000000173a4 R15: 00007ffdc23fe2e0