syzbot
INFO: rcu detected stall in sock_alloc_file (2)
Status:
upstream: reported on 2026/04/01 17:08
Reported-by: syzbot+f74682e9cfcbf29e3c25@syzkaller.appspotmail.com
First crash: 171d, last: 5h39m
Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { P6714 0-.... } 2690 jiffies s: 10285 root: 0x1/T
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6716 Comm: syz.5.564 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__sanitizer_cov_trace_const_cmp8+0x0/0x80 kernel/kcov.c:317
Code: 28 4d 39 ca 77 22 89 ff 89 f6 49 ff c0 4c 89 01 48 c7 44 11 08 05 00 00 00 48 89 7c 11 10 48 89 74 11 18 48 89 44 11 20 c3 90 <48> 8b 04 24 65 48 8b 0d 74 38 80 7e 65 8b 15 75 38 80 7e 81 e2 00
RSP: 0018:ffffc90000007178 EFLAGS: 00000046
RAX: ffffffff81a4c092 RBX: ffffc90000007320 RCX: ffff88804cab0000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000007270 R08: ffffc900000072f7 R09: ffffc900000072c0
R10: dffffc0000000000 R11: fffff52000000e5f R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffffc900000075c0
FS: 00007f453660e6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f45365aaff8 CR3: 000000005441d000 CR4: 00000000003506f0
DR0: 0000000000000002 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
<IRQ>
perf_prepare_sample+0x77e/0x2020 kernel/events/core.c:7588
__perf_event_output kernel/events/core.c:7740 [inline]
perf_event_output_forward+0x197/0x2f0 kernel/events/core.c:7760
__perf_event_overflow+0x457/0x630 kernel/events/core.c:9506
perf_swevent_overflow+0x19b/0x230 kernel/events/core.c:9589
perf_swevent_event+0x458/0x570 kernel/events/core.c:-1
perf_tp_event+0x36b/0xc10 kernel/events/core.c:10074
perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10042
perf_trace_preemptirq_template+0x268/0x320 include/trace/events/preemptirq.h:14
trace_irq_enable_rcuidle+0xd3/0x140 include/trace/events/preemptirq.h:40
trace_hardirqs_on+0x24/0x40 kernel/trace/trace_preemptirq.c:44
asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728
RIP: 0010:rcu_read_unlock_special+0x7f/0x510 kernel/rcu/tree_plugin.h:685
Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 32 7b 95 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc90000007a00 EFLAGS: 00000206
RAX: 2122ba908ad7be00 RBX: 1ffff92000000f48 RCX: 2122ba908ad7be00
RDX: dffffc0000000000 RSI: ffffffff8a8c18a0 RDI: ffffffff8adf68a0
RBP: ffffc90000007b00 R08: ffff8880b8e357cb R09: 1ffff110171c6af9
R10: dffffc0000000000 R11: ffffed10171c6afa R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8e3bb00 R15: 0000000000000001
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
rcu_read_unlock include/linux/rcupdate.h:823 [inline]
process_backlog+0x3ff/0x710 net/core/dev.c:6062
__napi_poll+0xbb/0x460 net/core/dev.c:6628
napi_poll net/core/dev.c:6695 [inline]
net_rx_action+0x622/0xbc0 net/core/dev.c:6809
handle_softirqs+0x291/0x910 kernel/softirq.c:596
__do_softirq kernel/softirq.c:630 [inline]
invoke_softirq kernel/softirq.c:470 [inline]
__irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:finish_task_switch+0x267/0x8e0 kernel/sched/core.c:5125
Code: d9 08 85 c0 0f 84 38 01 00 00 48 85 db 0f 85 57 01 00 00 0f 1f 44 00 00 4c 89 e7 e8 93 20 e3 08 e8 1e 18 2f 00 fb 4c 8b 65 b8 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0
RSP: 0018:ffffc90004977800 EFLAGS: 00000286
RAX: 2122ba908ad7be00 RBX: 0000000000000000 RCX: 2122ba908ad7be00
RDX: dffffc0000000000 RSI: ffffffff8a8c18a0 RDI: ffffffff8adf68a0
RBP: ffffc90004977850 R08: ffff8880b8e357cb R09: 1ffff110171c6af9
R10: dffffc0000000000 R11: ffffed10171c6afa R12: ffff88804cab0000
R13: 1ffff110171c76f2 R14: dffffc0000000000 R15: ffff8880b8e3b790
context_switch kernel/sched/core.c:5249 [inline]
__schedule+0x1087/0x4030 kernel/sched/core.c:6563
preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6875
irqentry_exit+0x63/0x70 kernel/entry/common.c:442
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:qlink_to_object mm/kasan/quarantine.c:140 [inline]
RIP: 0010:qlink_free mm/kasan/quarantine.c:145 [inline]
RIP: 0010:qlist_free_all+0x40/0xe0 mm/kasan/quarantine.c:187
Code: 00 49 89 f6 48 89 fb 49 bd 00 00 00 00 00 fc ff df 49 89 ef 4d 89 f4 4d 85 f6 75 0b 4c 89 ff e8 66 03 00 00 49 89 c4 49 8b 2f <49> 63 84 24 c0 00 00 00 49 29 c7 4c 89 e7 4c 89 fe e8 8a ec ff ff
RSP: 0018:ffffc90004977b60 EFLAGS: 00000282
RAX: ffff888140a52500 RBX: ffffc90004977ba0 RCX: ffffea000175e180
RDX: ffffea0000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff888073377000 R08: ffff88805d082f00 R09: 0000000080100003
R10: dffffc0000000000 R11: ffffed10171c6afa R12: ffff888140a52500
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff88805d786dc0
kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:294
__kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:306
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook+0x4b/0x490 mm/slab.h:737
slab_alloc_node mm/slub.c:3359 [inline]
slab_alloc mm/slub.c:3367 [inline]
__kmem_cache_alloc_lru mm/slub.c:3374 [inline]
kmem_cache_alloc+0x18b/0x2f0 mm/slub.c:3383
kmem_cache_zalloc include/linux/slab.h:689 [inline]
__alloc_file+0x25/0x230 fs/file_table.c:138
alloc_empty_file+0x90/0x180 fs/file_table.c:187
alloc_file+0x5b/0x5f0 fs/file_table.c:229
alloc_file_pseudo+0x180/0x200 fs/file_table.c:272
sock_alloc_file+0xb3/0x240 net/socket.c:467
__sys_socketpair+0x372/0x540 net/socket.c:1764
__do_sys_socketpair net/socket.c:1786 [inline]
__se_sys_socketpair net/socket.c:1783 [inline]
__x64_sys_socketpair+0x97/0xb0 net/socket.c:1783
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f453579e159
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:00007f453660e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000035
RAX: ffffffffffffffda RBX: 00007f4535a25fa0 RCX: 00007f453579e159
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001
RBP: 00007f453583506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4535a26038 R14: 00007f4535a25fa0 R15: 00007ffc17848f58
</TASK>
net_ratelimit: 6089 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:17, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:17, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:17, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:17, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:17, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:17, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:17, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:17, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:17, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:17, vlan:0)
net_ratelimit: 6430 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:17, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:17, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:17, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:17, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:17, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:17, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:17, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:17, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:17, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:17, vlan:0)
Struck through repros no longer work on HEAD.