[v6.6] INFO: rcu detected stall in aoecmd_cfg

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Feb 28, 2026, 11:23:33 PM (2 days ago) Feb 28
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Hello,

syzbot found the following issue on:

HEAD commit: 7a137e9bfa0e Linux 6.6.127
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16ae2d5a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2a950bf7c0bff9f9
dashboard link: https://syzkaller.appspot.com/bug?extid=f9903e1b974e2be88645
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1417fc31c535/disk-7a137e9b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/496475beec73/vmlinux-7a137e9b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/bba551b79079/bzImage-7a137e9b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f9903e...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5764/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=51765, q=26 ncpus=2)
task:syz-executor state:R running task stack:21384 pid:5764 ppid:5762 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867
preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
__raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
_raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
copy_pte_range mm/memory.c:1107 [inline]
copy_pmd_range mm/memory.c:1168 [inline]
copy_pud_range mm/memory.c:1205 [inline]
copy_p4d_range mm/memory.c:1229 [inline]
copy_page_range+0x2ba0/0x3670 mm/memory.c:1323
dup_mmap kernel/fork.c:764 [inline]
dup_mm kernel/fork.c:1692 [inline]
copy_mm+0x11cb/0x1d50 kernel/fork.c:1741
copy_process+0x16f7/0x3d80 kernel/fork.c:2506
kernel_clone+0x24b/0x8a0 kernel/fork.c:2914
__do_sys_clone kernel/fork.c:3057 [inline]
__se_sys_clone kernel/fork.c:3041 [inline]
__x64_sys_clone+0x1b7/0x230 kernel/fork.c:3041
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fe823bc5212
RSP: 002b:00007ffeb3891f90 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffeb3891f90 RCX: 00007fe823bc5212
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffeb389211c R08: 0000000000000000 R09: 0000000000000001
R10: 0000555574b107d0 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000000927c0 R14: 00000000000668ba R15: 00007ffeb3892170
</TASK>
rcu: rcu_preempt kthread starved for 10523 jiffies! g51765 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:26760 pid:17 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x9d/0x3b0 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
</TASK>
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: 12184 Comm: syz.0.1760 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:85 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:102 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:127 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:178 [inline]
RIP: 0010:kasan_check_range+0x89/0x290 mm/kasan/generic.c:187
Code: 00 fc ff df 4d 8d 34 19 4d 89 f4 4d 29 dc 49 83 fc 10 7f 29 4d 85 e4 0f 84 3d 01 00 00 4c 89 cb 48 f7 d3 4c 01 fb 41 80 3b 00 <0f> 85 8d 01 00 00 49 ff c3 48 ff c3 75 ee e9 1d 01 00 00 44 89 dd
RSP: 0018:ffffc900001efdc8 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffffffffffffffff RCX: ffffffff81682117
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e8adea8
RBP: ffffc900001eff08 R08: ffffffff8e8adeaf R09: 1ffffffff1d15bd5
R10: dffffc0000000000 R11: fffffbfff1d15bd5 R12: 0000000000000001
R13: ffffffff8d131fa0 R14: fffffbfff1d15bd6 R15: 1ffffffff1d15bd5
FS: 00007fc551e826c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555935d79e8 CR3: 0000000067e39000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
<IRQ>
instrument_atomic_read include/linux/instrumented.h:68 [inline]
_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
cpumask_test_cpu include/linux/cpumask.h:504 [inline]
cpu_online include/linux/cpumask.h:1082 [inline]
trace_lock_acquire include/trace/events/lock.h:24 [inline]
lock_acquire+0xb7/0x420 kernel/locking/lockdep.c:5725
rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
rcu_read_lock include/linux/rcupdate.h:786 [inline]
is_bpf_text_address+0x47/0x2a0 kernel/bpf/core.c:741
kernel_text_address+0xa0/0xd0 kernel/extable.c:125
__kernel_text_address+0xd/0x30 kernel/extable.c:79
unwind_get_return_address+0x5d/0xc0 arch/x86/kernel/unwind_orc.c:369
perf_callchain_kernel+0x304/0x690 arch/x86/events/core.c:2781
get_perf_callchain+0x231/0x510 kernel/events/callchain.c:204
perf_callchain kernel/events/core.c:7740 [inline]
perf_sample_save_callchain include/linux/perf_event.h:1232 [inline]
perf_prepare_sample+0x3c7/0x1df0 kernel/events/core.c:7784
__perf_event_output kernel/events/core.c:7972 [inline]
perf_event_output_forward+0x187/0x3e0 kernel/events/core.c:7993
__perf_event_overflow+0x447/0x630 kernel/events/core.c:9718
perf_swevent_overflow kernel/events/core.c:9794 [inline]
perf_swevent_event+0x324/0x630 kernel/events/core.c:-1
perf_tp_event+0x54f/0x1450 kernel/events/core.c:10344
perf_trace_run_bpf_submit+0xf4/0x1c0 kernel/events/core.c:10268
perf_trace_preemptirq_template+0x269/0x330 include/trace/events/preemptirq.h:14
trace_irq_enable+0xbb/0xe0 include/trace/events/preemptirq.h:40
trace_hardirqs_on+0x18/0x40 kernel/trace/trace_preemptirq.c:56
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:get_current arch/x86/include/asm/current.h:41 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:244 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x8/0x90 kernel/kcov.c:313
Code: 08 03 00 00 00 48 89 7c 11 10 48 89 74 11 18 48 89 44 11 20 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 15 f0 9c 7c 7e 65 8b 0d f1 9c 7c 7e 81 e1 00 01 ff 00 74
RSP: 0018:ffffc900001f09e8 EFLAGS: 00000206
RAX: ffffffff88722d89 RBX: dffffc0000000000 RCX: ffff8880270e5a00
RDX: 0000000000000100 RSI: 0000000000000100 RDI: 0000000000000181
RBP: ffffc900001f0a3c R08: 0000000057ab2a41 R09: 0000000000000000
R10: ffff888025ca1140 R11: fffffbfff1d15bd6 R12: 0000000000000100
R13: 0000000000000820 R14: 0000000000000820 R15: 1ffff9200003e147
kmalloc_reserve+0x59/0x240 net/core/skbuff.c:560
__alloc_skb+0x138/0x2c0 net/core/skbuff.c:653
alloc_skb include/linux/skbuff.h:1284 [inline]
new_skb drivers/block/aoe/aoecmd.c:66 [inline]
aoecmd_cfg_pkts drivers/block/aoe/aoecmd.c:430 [inline]
aoecmd_cfg+0x2c5/0xa50 drivers/block/aoe/aoecmd.c:1374
call_timer_fn+0x189/0x540 kernel/time/timer.c:1701
expire_timers kernel/time/timer.c:1752 [inline]
__run_timers+0x542/0x800 kernel/time/timer.c:2023
run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036
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+0xd3/0x190 kernel/softirq.c:661
irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:generic_exec_single+0x481/0x4f0 kernel/smp.c:418
Code: 75 11 e8 72 03 0b 00 48 85 db 75 16 e8 68 03 0b 00 eb 15 e8 61 03 0b 00 e8 cc 5a 08 09 48 85 db 74 ea e8 52 03 0b 00 fb 31 c0 <48> c7 44 24 20 0e 36 e0 45 4b c7 04 2c 00 00 00 00 43 c7 44 2c 08
RSP: 0018:ffffc9000c7dfa00 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000200 RCX: ffff8880270e5a00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000c7dfad0 R08: ffffffff911bf5ff R09: 1ffffffff2237ebf
R10: dffffc0000000000 R11: fffffbfff2237ec0 R12: 1ffff920018fbf44
R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff920018fbf65
smp_call_function_single+0x36d/0x5a0 kernel/smp.c:647
task_function_call kernel/events/core.c:120 [inline]
perf_install_in_context+0x5be/0x920 kernel/events/core.c:2948
__do_sys_perf_event_open kernel/events/core.c:12915 [inline]
__se_sys_perf_event_open+0x1836/0x1c50 kernel/events/core.c:12567
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc550f9c799
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc551e82028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 00007fc551215fa0 RCX: 00007fc550f9c799
RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000200000000140
RBP: 00007fc551032bd9 R08: 0000000000000002 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc551216038 R14: 00007fc551215fa0 R15: 00007ffc7055cd48
</TASK>


---
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