[v5.15] INFO: rcu detected stall in pep_sock_unhash
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syzbot
Nov 1, 2025, 3:55:25 AM (yesterday) Nov 1
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: cc5ec8769306 Linux 5.15.196
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=124c3f34580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e1bb6d24ef2164eb
dashboard link: https://syzkaller.appspot.com/bug?extid=91865782e6c843761d3d
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ed7568bc5bb4/disk-cc5ec876.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e343e0aaac77/vmlinux-cc5ec876.xz
kernel image: https://storage.googleapis.com/syzbot-assets/089870f2a980/bzImage-cc5ec876.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+918657...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-....: (11 ticks this GP) idle=cad/1/0x4000000000000002 softirq=27464/27464 fqs=2277
(detected by 1, t=10503 jiffies, g=33521, q=4230)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 9925 Comm: syz.2.1442 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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:128 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0x7b/0x290 mm/kasan/generic.c:189
Code: 5c 37 ff 48 c1 eb 03 4e 8d 14 3b 4d 89 d6 4d 29 ce 49 83 fe 10 7f 26 4d 85 f6 0f 84 39 01 00 00 48 f7 d3 4c 01 db 41 80 39 00 <0f> 85 c1 01 00 00 49 ff c1 48 ff c3 75 ee e9 1c 01 00 00 44 89 cb
RSP: 0018:ffffc90000006fa0 EFLAGS: 00000046
RAX: 0000000000000101 RBX: ffffffffffffffff RCX: ffffffff81645fbf
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff88805aa28000
RBP: ffffc900000070a0 R08: dffffc0000000000 R09: ffffed100b545000
R10: ffffed100b545001 R11: 1ffff1100b545000 R12: ffffffff8c120c00
R13: 0000000000000000 R14: 0000000000000001 R15: dffffc0000000001
FS: 00007f18fa9816c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005567018264b0 CR3: 000000005d97b000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
<IRQ>
instrument_atomic_write include/linux/instrumented.h:86 [inline]
set_bit include/asm-generic/bitops/instrumented-atomic.h:28 [inline]
set_ti_thread_flag include/linux/thread_info.h:89 [inline]
set_tsk_thread_flag include/linux/sched.h:1968 [inline]
set_tsk_need_resched include/linux/sched.h:1999 [inline]
rcu_read_unlock_special+0x25f/0x480 kernel/rcu/tree_plugin.h:659
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
rcu_read_unlock include/linux/rcupdate.h:772 [inline]
__perf_event_output kernel/events/core.c:7813 [inline]
perf_event_output_forward+0x216/0x280 kernel/events/core.c:7822
__perf_event_overflow+0x364/0x530 kernel/events/core.c:9515
perf_swevent_overflow kernel/events/core.c:9591 [inline]
perf_swevent_event+0x4ad/0x530 kernel/events/core.c:9629
perf_tp_event+0x32c/0xb50 kernel/events/core.c:10047
perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021
perf_trace_preemptirq_template+0x2be/0x380 include/trace/events/preemptirq.h:14
trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40
trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x84/0x480 kernel/rcu/tree_plugin.h:674
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 ed 11 9e 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc900000077a0 EFLAGS: 00000206
RAX: ea9631b890cfbe00 RBX: 1ffff92000000ef8 RCX: ea9631b890cfbe00
RDX: dffffc0000000000 RSI: ffffffff8a0b1c60 RDI: ffffffff8a59e580
RBP: ffffc90000007880 R08: dffffc0000000000 R09: fffffbfff1ff7c39
R10: fffffbfff1ff7c39 R11: 1ffffffff1ff7c38 R12: ffffffff8c120c00
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
rcu_read_unlock include/linux/rcupdate.h:772 [inline]
ndisc_send_skb+0xdc4/0x14a0 net/ipv6/ndisc.c:521
addrconf_rs_timer+0x2b8/0x600 net/ipv6/addrconf.c:3956
call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451
expire_timers kernel/time/timer.c:1496 [inline]
__run_timers+0x525/0x7c0 kernel/time/timer.c:1767
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
handle_softirqs+0x328/0x820 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x12f/0x220 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:finish_lock_switch+0x134/0x280 kernel/sched/core.c:4804
Code: be ff ff ff ff e8 7c fc 55 08 85 c0 74 4a 4d 85 ff 75 66 0f 1f 44 00 00 48 89 df e8 76 67 5f 08 e8 11 76 2a 00 fb 48 83 c4 08 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 48 89 df e8 d9 0f fe ff 43 80 3c
RSP: 0018:ffffc90003bef668 EFLAGS: 00000282
RAX: ea9631b890cfbe00 RBX: ffff8880b903a340 RCX: ea9631b890cfbe00
RDX: dffffc0000000000 RSI: ffffffff8a0b1c60 RDI: ffffffff8a59e580
RBP: 1ffff11017207613 R08: dffffc0000000000 R09: fffffbfff1ff7c43
R10: fffffbfff1ff7c43 R11: 1ffffffff1ff7c42 R12: 1ffff110172075c1
R13: dffffc0000000000 R14: ffff8880b903ae08 R15: 0000000000000000
finish_task_switch+0x12f/0x640 kernel/sched/core.c:4921
context_switch kernel/sched/core.c:5052 [inline]
__schedule+0x11c3/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
exp_funnel_lock kernel/rcu/tree_exp.h:313 [inline]
synchronize_rcu_expedited+0x5fa/0x6b0 kernel/rcu/tree_exp.h:845
synchronize_rcu+0x107/0x190 kernel/rcu/tree.c:3802
pep_sock_unhash+0x200/0x2e0 net/phonet/pep.c:1341
sk_common_release+0xa0/0x310 net/core/sock.c:3468
pep_sock_close+0x78/0x620 net/phonet/pep.c:740
pn_socket_release+0x91/0xb0 net/phonet/socket.c:34
__sock_release net/socket.c:651 [inline]
sock_close+0xd5/0x240 net/socket.c:1346
__fput+0x234/0x930 fs/file_table.c:311
task_work_run+0x125/0x1a0 kernel/task_work.c:188
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
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: 0033:0x7f18fc719fc9
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:00007f18fa981038 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 00007f18fc970fa0 RCX: 00007f18fc719fc9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007f18fc79cf91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f18fc971038 R14: 00007f18fc970fa0 R15: 00007ffed36e1318
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
syzbot found the following issue on:
HEAD commit: cc5ec8769306 Linux 5.15.196
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=124c3f34580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e1bb6d24ef2164eb
dashboard link: https://syzkaller.appspot.com/bug?extid=91865782e6c843761d3d
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ed7568bc5bb4/disk-cc5ec876.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e343e0aaac77/vmlinux-cc5ec876.xz
kernel image: https://storage.googleapis.com/syzbot-assets/089870f2a980/bzImage-cc5ec876.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+918657...@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-....: (11 ticks this GP) idle=cad/1/0x4000000000000002 softirq=27464/27464 fqs=2277
(detected by 1, t=10503 jiffies, g=33521, q=4230)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 9925 Comm: syz.2.1442 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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:128 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0x7b/0x290 mm/kasan/generic.c:189
Code: 5c 37 ff 48 c1 eb 03 4e 8d 14 3b 4d 89 d6 4d 29 ce 49 83 fe 10 7f 26 4d 85 f6 0f 84 39 01 00 00 48 f7 d3 4c 01 db 41 80 39 00 <0f> 85 c1 01 00 00 49 ff c1 48 ff c3 75 ee e9 1c 01 00 00 44 89 cb
RSP: 0018:ffffc90000006fa0 EFLAGS: 00000046
RAX: 0000000000000101 RBX: ffffffffffffffff RCX: ffffffff81645fbf
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff88805aa28000
RBP: ffffc900000070a0 R08: dffffc0000000000 R09: ffffed100b545000
R10: ffffed100b545001 R11: 1ffff1100b545000 R12: ffffffff8c120c00
R13: 0000000000000000 R14: 0000000000000001 R15: dffffc0000000001
FS: 00007f18fa9816c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005567018264b0 CR3: 000000005d97b000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
<IRQ>
instrument_atomic_write include/linux/instrumented.h:86 [inline]
set_bit include/asm-generic/bitops/instrumented-atomic.h:28 [inline]
set_ti_thread_flag include/linux/thread_info.h:89 [inline]
set_tsk_thread_flag include/linux/sched.h:1968 [inline]
set_tsk_need_resched include/linux/sched.h:1999 [inline]
rcu_read_unlock_special+0x25f/0x480 kernel/rcu/tree_plugin.h:659
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
rcu_read_unlock include/linux/rcupdate.h:772 [inline]
__perf_event_output kernel/events/core.c:7813 [inline]
perf_event_output_forward+0x216/0x280 kernel/events/core.c:7822
__perf_event_overflow+0x364/0x530 kernel/events/core.c:9515
perf_swevent_overflow kernel/events/core.c:9591 [inline]
perf_swevent_event+0x4ad/0x530 kernel/events/core.c:9629
perf_tp_event+0x32c/0xb50 kernel/events/core.c:10047
perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021
perf_trace_preemptirq_template+0x2be/0x380 include/trace/events/preemptirq.h:14
trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40
trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x84/0x480 kernel/rcu/tree_plugin.h:674
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 ed 11 9e 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc900000077a0 EFLAGS: 00000206
RAX: ea9631b890cfbe00 RBX: 1ffff92000000ef8 RCX: ea9631b890cfbe00
RDX: dffffc0000000000 RSI: ffffffff8a0b1c60 RDI: ffffffff8a59e580
RBP: ffffc90000007880 R08: dffffc0000000000 R09: fffffbfff1ff7c39
R10: fffffbfff1ff7c39 R11: 1ffffffff1ff7c38 R12: ffffffff8c120c00
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
rcu_read_unlock include/linux/rcupdate.h:772 [inline]
ndisc_send_skb+0xdc4/0x14a0 net/ipv6/ndisc.c:521
addrconf_rs_timer+0x2b8/0x600 net/ipv6/addrconf.c:3956
call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451
expire_timers kernel/time/timer.c:1496 [inline]
__run_timers+0x525/0x7c0 kernel/time/timer.c:1767
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
handle_softirqs+0x328/0x820 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x12f/0x220 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:finish_lock_switch+0x134/0x280 kernel/sched/core.c:4804
Code: be ff ff ff ff e8 7c fc 55 08 85 c0 74 4a 4d 85 ff 75 66 0f 1f 44 00 00 48 89 df e8 76 67 5f 08 e8 11 76 2a 00 fb 48 83 c4 08 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 48 89 df e8 d9 0f fe ff 43 80 3c
RSP: 0018:ffffc90003bef668 EFLAGS: 00000282
RAX: ea9631b890cfbe00 RBX: ffff8880b903a340 RCX: ea9631b890cfbe00
RDX: dffffc0000000000 RSI: ffffffff8a0b1c60 RDI: ffffffff8a59e580
RBP: 1ffff11017207613 R08: dffffc0000000000 R09: fffffbfff1ff7c43
R10: fffffbfff1ff7c43 R11: 1ffffffff1ff7c42 R12: 1ffff110172075c1
R13: dffffc0000000000 R14: ffff8880b903ae08 R15: 0000000000000000
finish_task_switch+0x12f/0x640 kernel/sched/core.c:4921
context_switch kernel/sched/core.c:5052 [inline]
__schedule+0x11c3/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
exp_funnel_lock kernel/rcu/tree_exp.h:313 [inline]
synchronize_rcu_expedited+0x5fa/0x6b0 kernel/rcu/tree_exp.h:845
synchronize_rcu+0x107/0x190 kernel/rcu/tree.c:3802
pep_sock_unhash+0x200/0x2e0 net/phonet/pep.c:1341
sk_common_release+0xa0/0x310 net/core/sock.c:3468
pep_sock_close+0x78/0x620 net/phonet/pep.c:740
pn_socket_release+0x91/0xb0 net/phonet/socket.c:34
__sock_release net/socket.c:651 [inline]
sock_close+0xd5/0x240 net/socket.c:1346
__fput+0x234/0x930 fs/file_table.c:311
task_work_run+0x125/0x1a0 kernel/task_work.c:188
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
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: 0033:0x7f18fc719fc9
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:00007f18fa981038 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 00007f18fc970fa0 RCX: 00007f18fc719fc9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007f18fc79cf91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f18fc971038 R14: 00007f18fc970fa0 R15: 00007ffed36e1318
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
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