rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4602/1:b..l P4605/1:b..l
(detected by 1, t=10502 jiffies, g=19541, q=267 ncpus=2)
task:udevd state:R running task stack:24768 pid:4605 ppid:3636 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6730
preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6754
preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
_raw_spin_unlock_irq+0x3c/0x40 kernel/locking/spinlock.c:202
spin_unlock_irq include/linux/spinlock.h:401 [inline]
loop_queue_work drivers/block/loop.c:894 [inline]
loop_queue_rq+0x9d9/0xac0 drivers/block/loop.c:1874
__blk_mq_issue_directly block/blk-mq.c:2631 [inline]
__blk_mq_try_issue_directly+0x4ab/0x7a0 block/blk-mq.c:2684
blk_mq_request_issue_directly block/blk-mq.c:2718 [inline]
blk_mq_plug_issue_direct+0x233/0x620 block/blk-mq.c:2738
blk_mq_flush_plug_list+0x7e7/0xd40 block/blk-mq.c:2838
__blk_flush_plug+0x3c6/0x440 block/blk-core.c:1179
blk_finish_plug+0x59/0x80 block/blk-core.c:1203
read_pages+0x646/0x840 mm/readahead.c:184
page_cache_ra_unbounded+0x690/0x770 mm/readahead.c:270
do_page_cache_ra mm/readahead.c:300 [inline]
force_page_cache_ra mm/readahead.c:331 [inline]
page_cache_sync_ra+0x3d7/0x490 mm/readahead.c:713
page_cache_sync_readahead include/linux/pagemap.h:1250 [inline]
filemap_get_pages mm/filemap.c:2665 [inline]
filemap_read+0x5ff/0x2f80 mm/filemap.c:2759
blkdev_read_iter+0x42d/0x570 block/fops.c:668
call_read_iter include/linux/fs.h:2259 [inline]
new_sync_read fs/read_write.c:389 [inline]
vfs_read+0x434/0x920 fs/read_write.c:470
ksys_read+0x143/0x240 fs/read_write.c:613
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f08433d3407
RSP: 002b:00007ffeccfcc7c0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f0843347880 RCX: 00007f08433d3407
RDX: 0000000000000200 RSI: 00007f084333f000 RDI: 0000000000000009
RBP: 00005558da69e050 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 0000000000ff8200 R14: 00005558da697a48 R15: 00007f08435ec39c
task:udevd state:R running task stack:24960 pid:4602 ppid:3636 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6730
preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6754
preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
_raw_spin_unlock_irq+0x3c/0x40 kernel/locking/spinlock.c:202
spin_unlock_irq include/linux/spinlock.h:401 [inline]
loop_queue_work drivers/block/loop.c:894 [inline]
loop_queue_rq+0x9d9/0xac0 drivers/block/loop.c:1874
__blk_mq_issue_directly block/blk-mq.c:2631 [inline]
__blk_mq_try_issue_directly+0x4ab/0x7a0 block/blk-mq.c:2684
blk_mq_request_issue_directly block/blk-mq.c:2718 [inline]
blk_mq_plug_issue_direct+0x233/0x620 block/blk-mq.c:2738
blk_mq_flush_plug_list+0x7e7/0xd40 block/blk-mq.c:2838
__blk_flush_plug+0x3c6/0x440 block/blk-core.c:1179
blk_finish_plug+0x59/0x80 block/blk-core.c:1203
read_pages+0x646/0x840 mm/readahead.c:184
page_cache_ra_unbounded+0x690/0x770 mm/readahead.c:270
do_page_cache_ra mm/readahead.c:300 [inline]
force_page_cache_ra mm/readahead.c:331 [inline]
page_cache_sync_ra+0x3d7/0x490 mm/readahead.c:713
page_cache_sync_readahead include/linux/pagemap.h:1250 [inline]
filemap_get_pages mm/filemap.c:2665 [inline]
filemap_read+0x5ff/0x2f80 mm/filemap.c:2759
blkdev_read_iter+0x42d/0x570 block/fops.c:668
call_read_iter include/linux/fs.h:2259 [inline]
new_sync_read fs/read_write.c:389 [inline]
vfs_read+0x434/0x920 fs/read_write.c:470
ksys_read+0x143/0x240 fs/read_write.c:613
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f08433d3407
RSP: 002b:00007ffeccfcc7c0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f0843347880 RCX: 00007f08433d3407
RDX: 0000000000000200 RSI: 00007f084333f000 RDI: 0000000000000009
RBP: 00005558da69e050 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 0000000000ff8200 R14: 00005558da6b85d8 R15: 00007f08435ec39c
rcu: rcu_preempt kthread timer wakeup didn't happen for 10567 jiffies! g19541 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=9090
rcu: rcu_preempt kthread starved for 10568 jiffies! g19541 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27840 pid:16 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
schedule_timeout+0x15c/0x280 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
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: 5406 Comm: syz.8.155 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:hrtimer_reprogram+0x0/0x3f0 kernel/time/hrtimer.c:830
Code: 00 e9 01 fa ff ff e8 cf fb 0f 00 48 c7 c7 40 3e 94 8c 48 89 de e8 e0 d5 bd 02 e9 a8 fc ff ff e8 b6 fb 0f 00 e9 ab f8 ff ff 90 <55> 41 57 41 56 41 55 41 54 53 48 83 ec 10 48 89 7c 24 08 e8 98 fb
RSP: 0018:ffffc90005bc7a48 EFLAGS: 00000093
RAX: ffffffff8170dff0 RBX: 0000000000000001 RCX: ffff88802d979dc0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff88802f4da3a0
RBP: 0000000000000010 R08: dffffc0000000000 R09: ffff88802f4da3a8
R10: ffffed1005e9b477 R11: 1ffff11005e9b475 R12: 1ffff11005e9b47a
R13: dffffc0000000000 R14: ffff8880b8e2a5cc R15: ffff8880b8e2a600
FS: 00007f7cd02d56c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc5588cb440 CR3: 000000002666a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
hrtimer_start_range_ns+0xb9a/0xfc0 kernel/time/hrtimer.c:1349
posixtimer_rearm+0x131/0x340 kernel/time/posix-timers.c:329
dequeue_signal+0x1b6/0x4b0 kernel/signal.c:704
get_signal+0x547/0x1350 kernel/signal.c:2751
arch_do_signal_or_restart+0xb7/0x1240 arch/x86/kernel/signal.c:871
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f7ccf38f749
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:00007f7cd02d5038 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f7ccf5e5fa0 RCX: 00007f7ccf38f749
RDX: 0000200000000300 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 00007f7ccf413f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7ccf5e6038 R14: 00007f7ccf5e5fa0 R15: 00007ffce22e0198