rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P10651
rcu: (detected by 0, t=10502 jiffies, g=42957, q=1878 ncpus=2)
task:syz.8.1524 state:R running task stack:27016 pid:10651 ppid:8878 flags:0x0000400e
Call Trace:
sched_show_task+0x481/0x5a0 kernel/sched/core.c:9178
rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:261 [inline]
print_other_cpu_stall+0xfa7/0x1340 kernel/rcu/tree_stall.h:637
check_cpu_stall kernel/rcu/tree_stall.h:809 [inline]
rcu_pending kernel/rcu/tree.c:3950 [inline]
rcu_sched_clock_irq+0x87c/0x1220 kernel/rcu/tree.c:2295
update_process_times+0x147/0x1b0 kernel/time/timer.c:2071
tick_sched_handle kernel/time/tick-sched.c:254 [inline]
tick_sched_timer+0x3a2/0x580 kernel/time/tick-sched.c:1492
__run_hrtimer kernel/time/hrtimer.c:1755 [inline]
__hrtimer_run_queues+0x4df/0xc40 kernel/time/hrtimer.c:1819
hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1881
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
__sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0x51/0xc0 arch/x86/kernel/apic/apic.c:1088
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:__sanitizer_cov_trace_switch+0x81/0x120 kernel/kcov.c:349
Code: 00 00 00 b9 01 00 00 00 48 85 c0 0f 84 ae 00 00 00 41 57 41 56 41 54 53 48 8b 54 24 20 65 4c 8b 05 a4 29 7e 7e 45 31 c9 eb 08 <49> ff c1 4c 39 c8 74 77 4e 8b 54 ce 10 65 44 8b 1d 92 29 7e 7e 41
RSP: 0018:ffffc90000007470 EFLAGS: 00000246
RAX: 0000000000000020 RBX: 000000ad54be5533 RCX: 0000000000000005
RDX: ffffffff8188902d RSI: ffffffff8cd79820 RDI: 0000000000000004
RBP: 0000000000000004 R08: ffff8880183f8000 R09: 0000000000000016
R10: 0000000000000016 R11: 0000000000000100 R12: ffff888018242038
R13: f800000000000000 R14: 0000000000000028 R15: 000000000006e4e4
check_buffer+0x24d/0x950 kernel/trace/ring_buffer.c:3495
__rb_reserve_next+0x511/0xd50 kernel/trace/ring_buffer.c:3624
rb_reserve_next_event kernel/trace/ring_buffer.c:3759 [inline]
ring_buffer_lock_reserve+0xae1/0xed0 kernel/trace/ring_buffer.c:3818
__trace_buffer_lock_reserve kernel/trace/trace.c:992 [inline]
trace_event_buffer_lock_reserve+0x1d0/0x6e0 kernel/trace/trace.c:2902
trace_event_buffer_reserve+0x29b/0x3c0 kernel/trace/trace_events.c:661
do_trace_event_raw_event_bpf_trace_printk kernel/trace/bpf_trace.h:11 [inline]
trace_event_raw_event_bpf_trace_printk+0x101/0x210 kernel/trace/bpf_trace.h:11
trace_bpf_trace_printk+0x142/0x1a0 kernel/trace/bpf_trace.h:11
____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline]
bpf_trace_printk+0x11f/0x190 kernel/trace/bpf_trace.c:371
bpf_prog_0605f9f479290f07+0x37/0x3b
bpf_dispatcher_nop_func include/linux/bpf.h:1213 [inline]
__bpf_prog_run include/linux/filter.h:612 [inline]
bpf_prog_run include/linux/filter.h:619 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline]
bpf_trace_run1+0x1c9/0x3b0 kernel/trace/bpf_trace.c:2360
__bpf_trace_rcu_utilization+0xa2/0xe0 include/trace/events/rcu.h:27
trace_rcu_utilization+0x179/0x1a0 include/trace/events/rcu.h:27
rcu_core+0x1341/0x1720 kernel/rcu/tree.c:2475
handle_softirqs+0x280/0x820 kernel/softirq.c:578
__do_softirq kernel/softirq.c:612 [inline]
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
sysvec_irq_work+0xa1/0xc0 arch/x86/kernel/irq_work.c:17
asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723
RIP: 0010:rcu_read_unlock_special+0x88/0x4c0 kernel/rcu/tree_plugin.h:682
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 39 58 93 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc9000b947c00 EFLAGS: 00000206
RAX: 8fb2ddb864dadf00 RBX: 1ffff92001728f88 RCX: 8fb2ddb864dadf00
RDX: dffffc0000000000 RSI: ffffffff8aaab9c0 RDI: ffffffff8afc66c0
RBP: ffffc9000b947cf0 R08: ffffffff90da3517 R09: 1ffffffff21b46a2
R10: dffffc0000000000 R11: fffffbfff21b46a3 R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000000246 R15: ffffffff8cd35518
__rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426
rcu_read_unlock+0x85/0xa0 include/linux/rcupdate.h:818
dput+0xe6/0x1e0 fs/dcache.c:911
__fput+0x5e5/0x970 fs/file_table.c:392
task_work_run+0x1ce/0x250 kernel/task_work.c:239
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f753638ebe9
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:00007ffe0b9c59c8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 000000000009c059 RCX: 00007f753638ebe9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f75365b7da0 R08: 0000000000000001 R09: 000000100b9c5cbf
R10: 0000001b2e820000 R11: 0000000000000246 R12: 00007f75365b5fac
R13: 00007f75365b5fa0 R14: ffffffffffffffff R15: 00007ffe0b9c5ae0
rcu: rcu_preempt kthread starved for 6036 jiffies! g42957 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:27368 pid:17 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
schedule+0xbd/0x170 kernel/sched/core.c:6773
schedule_timeout+0x160/0x280 kernel/time/timer.c:2167
rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 7713 Comm: kworker/u4:9 Not tainted 6.6.102-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:__sanitizer_cov_trace_switch+0x81/0x120 kernel/kcov.c:349
Code: 00 00 00 b9 01 00 00 00 48 85 c0 0f 84 ae 00 00 00 41 57 41 56 41 54 53 48 8b 54 24 20 65 4c 8b 05 a4 29 7e 7e 45 31 c9 eb 08 <49> ff c1 4c 39 c8 74 77 4e 8b 54 ce 10 65 44 8b 1d 92 29 7e 7e 41
RSP: 0018:ffffc900001f0448 EFLAGS: 00000246
RAX: 0000000000000020 RBX: 0000000000000004 RCX: 0000000000000005
RDX: ffffffff818755b5 RSI: ffffffff8cd79180 RDI: 0000000000000004
RBP: 0000000000000f8c R08: ffff888028d80000 R09: 000000000000000c
R10: 000000000000000c R11: 0000000000000100 R12: dffffc0000000000
R13: f800000000000000 R14: ffff88801c66418c R15: 0000000000045b44
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb2b46636e6 CR3: 000000000cb30000 CR4: 00000000003506e0
DR0: ffff8880b8927a20 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
rb_event_length+0x45/0x3f0 kernel/trace/ring_buffer.c:198
check_buffer+0x542/0x950 kernel/trace/ring_buffer.c:3491
__rb_reserve_next+0x511/0xd50 kernel/trace/ring_buffer.c:3624
rb_reserve_next_event kernel/trace/ring_buffer.c:3759 [inline]
ring_buffer_lock_reserve+0xae1/0xed0 kernel/trace/ring_buffer.c:3818
__trace_buffer_lock_reserve kernel/trace/trace.c:992 [inline]
trace_event_buffer_lock_reserve+0x1d0/0x6e0 kernel/trace/trace.c:2902
trace_event_buffer_reserve+0x29b/0x3c0 kernel/trace/trace_events.c:661
do_trace_event_raw_event_bpf_trace_printk kernel/trace/bpf_trace.h:11 [inline]
trace_event_raw_event_bpf_trace_printk+0x101/0x210 kernel/trace/bpf_trace.h:11
trace_bpf_trace_printk+0x142/0x1a0 kernel/trace/bpf_trace.h:11
____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline]
bpf_trace_printk+0x11f/0x190 kernel/trace/bpf_trace.c:371
bpf_prog_0605f9f479290f07+0x37/0x3b
bpf_dispatcher_nop_func include/linux/bpf.h:1213 [inline]
__bpf_prog_run include/linux/filter.h:612 [inline]
bpf_prog_run include/linux/filter.h:619 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline]
bpf_trace_run1+0x1c9/0x3b0 kernel/trace/bpf_trace.c:2360
__bpf_trace_rcu_utilization+0xa2/0xe0 include/trace/events/rcu.h:27
trace_rcu_utilization+0x179/0x1a0 include/trace/events/rcu.h:27
rcu_core+0x1341/0x1720 kernel/rcu/tree.c:2475
handle_softirqs+0x280/0x820 kernel/softirq.c:578
__do_softirq kernel/softirq.c:612 [inline]
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
sysvec_irq_work+0xa1/0xc0 arch/x86/kernel/irq_work.c:17
asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723
RIP: 0010:rcu_read_unlock_special+0x88/0x4c0 kernel/rcu/tree_plugin.h:682
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 39 58 93 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc9000cbfe380 EFLAGS: 00000206
RAX: 97095b5a2e0f2a00 RBX: 1ffff9200197fc78 RCX: 97095b5a2e0f2a00
RDX: dffffc0000000000 RSI: ffffffff8aaab9c0 RDI: ffffffff8afc66c0
RBP: ffffc9000cbfe480 R08: ffffffff90da3507 R09: 1ffffffff21b46a0
R10: dffffc0000000000 R11: fffffbfff21b46a1 R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000000246 R15: ffffffff8cd35518
__rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426
rcu_read_unlock include/linux/rcupdate.h:818 [inline]
pte_unmap include/linux/pgtable.h:113 [inline]
page_vma_mapped_walk_done include/linux/rmap.h:419 [inline]
not_found mm/page_vma_mapped.c:12 [inline]
page_vma_mapped_walk+0x196b/0x1bc0 mm/page_vma_mapped.c:297
page_vma_mkclean_one+0x5ab/0x720 mm/rmap.c:950
page_mkclean_one+0x1ec/0x3b0 mm/rmap.c:1003
rmap_walk_file+0x3f8/0x760 mm/rmap.c:2503
rmap_walk mm/rmap.c:2521 [inline]
folio_mkclean+0x1c8/0x330 mm/rmap.c:1035
folio_clear_dirty_for_io+0x20e/0xc30 mm/page-writeback.c:2918
mpage_submit_folio+0x7d/0x3c0 fs/ext4/inode.c:1889
mpage_process_page_bufs+0x6e1/0x8f0 fs/ext4/inode.c:2021
mpage_prepare_extent_to_map+0xde9/0x1c80 fs/ext4/inode.c:2529
ext4_do_writepages+0xb19/0x38d0 fs/ext4/inode.c:2671
ext4_writepages+0x1a8/0x2f0 fs/ext4/inode.c:2807
do_writepages+0x3a2/0x600 mm/page-writeback.c:2575
__writeback_single_inode+0x153/0xee0 fs/fs-writeback.c:1625
writeback_sb_inodes+0x77c/0xef0 fs/fs-writeback.c:1916
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:1987
wb_writeback+0x464/0xba0 fs/fs-writeback.c:2097
wb_check_old_data_flush fs/fs-writeback.c:2201 [inline]
wb_do_writeback fs/fs-writeback.c:2254 [inline]
wb_workfn+0xabc/0xe20 fs/fs-writeback.c:2282
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293