Hello,
syzbot found the following issue on:
HEAD commit: eceeec79dbc6 Linux 5.15.210
git tree: linux-5.15.y
console output:
https://syzkaller.appspot.com/x/log.txt?x=16247bfe580000
kernel config:
https://syzkaller.appspot.com/x/.config?x=6f8e2266b61925dc
dashboard link:
https://syzkaller.appspot.com/bug?extid=ed6f117c416c83d80d53
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image:
https://storage.googleapis.com/syzbot-assets/03366f3fc8c2/disk-eceeec79.raw.xz
vmlinux:
https://storage.googleapis.com/syzbot-assets/19718022a397/vmlinux-eceeec79.xz
kernel image:
https://storage.googleapis.com/syzbot-assets/642c77037a7f/bzImage-eceeec79.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by:
syzbot+ed6f11...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 1-...!: (5284 ticks this GP) idle=9ef/1/0x4000000000000000 softirq=10941/10951 fqs=0
(t=10501 jiffies g=12721 q=505)
rcu: rcu_preempt kthread starved for 10502 jiffies! g12721 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:28112 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11c3/0x4350 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/0x11f0 kernel/rcu/tree.c:1972
rcu_gp_kthread+0x9a/0x370 kernel/rcu/tree.c:2145
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
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: 5273 Comm: syz.3.268 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:434 [inline]
RIP: 0010:__pv_queued_spin_lock_slowpath+0x520/0x9b0 kernel/locking/qspinlock.c:508
Code: 8b 44 24 18 c6 00 00 48 8b 44 24 10 42 0f b6 04 28 84 c0 0f 85 1c 01 00 00 48 8d 43 01 c6 00 01 41 bc 00 80 ff ff eb 07 f3 90 <41> ff c4 74 47 43 0f b6 04 2e 84 c0 75 2b 80 3b 00 75 eb 48 89 df
RSP: 0018:ffffc9000308f6e0 EFLAGS: 00000206
RAX: 0000000000000000 RBX: ffffffff8c3dcbc0 RCX: 34f910ed065a7000
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a2840
RBP: ffffc9000308f7d8 R08: ffffffff901e90c7 R09: 1ffffffff203d218
R10: dffffc0000000000 R11: fffffbfff203d219 R12: 00000000ffffe691
R13: dffffc0000000000 R14: 1ffffffff187b978 R15: ffff8880b9030001
FS: 00007f57b90176c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000639000 CR3: 000000006104e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
<TASK>
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline]
queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51
queued_spin_lock include/asm-generic/qspinlock.h:85 [inline]
do_raw_spin_lock+0x265/0x2f0 kernel/locking/spinlock_debug.c:115
spin_lock include/linux/spinlock.h:364 [inline]
preload_this_cpu_lock mm/vmalloc.c:1507 [inline]
alloc_vmap_area+0x677/0x1b30 mm/vmalloc.c:1549
__get_vm_area_node+0x14f/0x2d0 mm/vmalloc.c:2430
__vmalloc_node_range+0xef/0x8b0 mm/vmalloc.c:3027
__vmalloc_node mm/vmalloc.c:3087 [inline]
__vmalloc+0x76/0x80 mm/vmalloc.c:3101
bpf_prog_alloc_no_stats+0x36/0x2c0 kernel/bpf/core.c:90
bpf_prog_alloc+0x1a/0x1e0 kernel/bpf/core.c:124
bpf_prog_load+0x7d1/0x14e0 kernel/bpf/syscall.c:2301
__sys_bpf+0x532/0x6f0 kernel/bpf/syscall.c:4657
__do_sys_bpf kernel/bpf/syscall.c:4761 [inline]
__se_sys_bpf kernel/bpf/syscall.c:4759 [inline]
__x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4759
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: 0033:0x7f57badbee59
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:00007f57b9017028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f57bb046fa0 RCX: 00007f57badbee59
RDX: 0000000000000094 RSI: 0000200000000b80 RDI: 0000000000000005
RBP: 00007f57bae54e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f57bb047038 R14: 00007f57bb046fa0 R15: 00007ffca245c328
</TASK>
NMI backtrace for cpu 1
CPU: 1 PID: 5264 Comm: syz.6.264 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
<IRQ>
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
rcu_dump_cpu_stacks+0x22d/0x380 kernel/rcu/tree_stall.h:349
print_cpu_stall+0x31f/0x5f0 kernel/rcu/tree_stall.h:633
check_cpu_stall kernel/rcu/tree_stall.h:727 [inline]
rcu_pending kernel/rcu/tree.c:3936 [inline]
rcu_sched_clock_irq+0x6ec/0x1120 kernel/rcu/tree.c:2619
update_process_times+0x193/0x200 kernel/time/timer.c:2021
tick_sched_handle kernel/time/tick-sched.c:254 [inline]
tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
__run_hrtimer kernel/time/hrtimer.c:1685 [inline]
__hrtimer_run_queues+0x4b0/0xb60 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x397/0x8b0 kernel/time/hrtimer.c:1811
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+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:kfree+0x17d/0x2a0 mm/slub.c:4565
Code: 0f 85 38 01 00 00 48 8d 4f 08 48 89 fe 48 83 ce 08 48 39 ce 0f 85 26 01 00 00 48 8d 4a 08 65 48 0f c7 0f 0f 94 c0 a8 01 74 a8 <65> 48 8b 04 25 28 00 00 00 48 3b 44 24 20 0f 85 8b 00 00 00 48 83
RSP: 0018:ffffc90000dd0a98 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff8880608fc400 RCX: 30335bac1d58c200
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a2840
RBP: 0000000000000000 R08: ffffffff901e90c7 R09: 1ffffffff203d218
R10: dffffc0000000000 R11: fffffbfff203d219 R12: ffff888016c41c80
R13: ffff88805fb5ba00 R14: ffffffff87df7757 R15: ffffea0001823f00
skb_free_head net/core/skbuff.c:655 [inline]
skb_release_data+0x667/0x830 net/core/skbuff.c:677
skb_release_all net/core/skbuff.c:742 [inline]
__kfree_skb net/core/skbuff.c:756 [inline]
kfree_skb_reason+0xaf/0x110 net/core/skbuff.c:776
kfree_skb include/linux/skbuff.h:1118 [inline]
x25_lapb_receive_frame+0x5d/0xf20 net/x25/x25_dev.c:143
__netif_receive_skb_one_core net/core/dev.c:5551 [inline]
netif_receive_skb_core+0x149/0x210 net/core/dev.c:5576
lapbeth_napi_poll+0x3e/0x80 drivers/net/wan/lapbether.c:99
__napi_poll+0xbb/0x430 net/core/dev.c:7101
napi_poll net/core/dev.c:7168 [inline]
net_rx_action+0x522/0xa80 net/core/dev.c:7258
handle_softirqs+0x336/0x830 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:instrument_atomic_read include/linux/instrumented.h:71 [inline]
RIP: 0010:atomic_long_read include/linux/atomic/atomic-instrumented.h:1183 [inline]
RIP: 0010:__purge_vmap_area_lazy+0xb16/0x1940 mm/vmalloc.c:1716
Code: 89 fe 48 89 da e8 ca d5 0a 00 4d 29 f7 49 c1 ef 0c 48 c7 c7 80 30 34 96 be 08 00 00 00 e8 d2 d1 0a 00 f0 4c 29 3d da ed 80 14 <48> c7 c7 80 30 34 96 be 08 00 00 00 e8 a9 d1 0a 00 48 8b 1d c2 ed
RSP: 0018:ffffc9000334f420 EFLAGS: 00000206
RAX: 0000000000000001 RBX: ffffc90001306000 RCX: ffffffff81b3429e
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff96343080
RBP: ffffc9000334f558 R08: ffffffff96343087 R09: 1ffffffff2c68610
R10: dffffc0000000000 R11: fffffbfff2c68611 R12: 000000000000b000
R13: ffff8880255efe48 R14: ffffc90001306000 R15: 0000000000000004
_vm_unmap_aliases+0x40b/0x4a0 mm/vmalloc.c:2114
change_page_attr_set_clr+0x317/0xc30 arch/x86/mm/pat/set_memory.c:1740
change_page_attr_clear arch/x86/mm/pat/set_memory.c:1797 [inline]
set_memory_ro+0x89/0xd0 arch/x86/mm/pat/set_memory.c:1943
bpf_jit_binary_lock_ro include/linux/filter.h:919 [inline]
bpf_int_jit_compile+0xbf27/0xc4d0 arch/x86/net/bpf_jit_comp.c:2478
bpf_prog_select_runtime+0x46f/0x7b0 kernel/bpf/core.c:1977
bpf_prog_load+0x100a/0x14e0 kernel/bpf/syscall.c:2358
__sys_bpf+0x532/0x6f0 kernel/bpf/syscall.c:4657
__do_sys_bpf kernel/bpf/syscall.c:4761 [inline]
__se_sys_bpf kernel/bpf/syscall.c:4759 [inline]
__x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4759
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: 0033:0x7f78d945de59
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:00007f78d76b6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f78d96e5fa0 RCX: 00007f78d945de59
RDX: 0000000000000048 RSI: 0000200000000200 RDI: 0000000000000005
RBP: 00007f78d94f3e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f78d96e6038 R14: 00007f78d96e5fa0 R15: 00007ffc5ac6c0e8
</TASK>
---
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