syzbot

 sign-in | mailing list | source | docs
🐞 Open [355]
🐞 Fixed [14]
🐞 Invalid [51]
⬇ Missing Backports [12]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
💬 Send us feedback

INFO: rcu detected stall in sock_alloc_file

Status: upstream: reported on 2025/08/25 21:35
Reported-by: syzbot+5a6092cba56b160f8439@syzkaller.appspotmail.com
First crash: 66d, last: 66d
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sock_alloc_file fs 1 1 706d 706d 0/29 closed as invalid on 2024/02/01 10:31
linux-5.15 INFO: rcu detected stall in sock_alloc_file 1 1 117d 117d 0/3 auto-obsoleted due to no activity on 2025/10/13 16:41
upstream INFO: rcu detected stall in sock_alloc_file (2) mm 1 6 285d 337d 0/29 auto-obsoleted due to no activity on 2025/04/19 00:40
linux-5.15 INFO: rcu detected stall in sock_alloc_file (2) 1 1 6d12h 6d12h 0/3 upstream: reported on 2025/10/24 19:33
linux-6.1 INFO: rcu detected stall in sock_alloc_file 1 1 57d 57d 0/3 upstream: reported on 2025/09/03 11:49

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-....: (1 GPs behind) idle=69c4/1/0x4000000000000000 softirq=21794/21795 fqs=5249
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number: 11485374          0            0
rcu: 	cputime:     4995      47522            0   ==> 52500(ms)
rcu: 	(detected by 1, t=10502 jiffies, g=25885, q=1272 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 8414 Comm: syz.4.938 Not tainted 6.6.102-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:check_kcov_mode kernel/kcov.c:182 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:245 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp8+0x27/0x80 kernel/kcov.c:320
Code: 0f 1f 00 f3 0f 1e fa 48 8b 04 24 65 48 8b 0d 90 2a 7e 7e 65 8b 15 91 2a 7e 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 57 <83> b9 1c 16 00 00 00 74 4e 8b 91 f8 15 00 00 83 fa 03 75 43 48 8b
RSP: 0018:ffffc90000007508 EFLAGS: 00000046
RAX: ffffffff81acc9ed RBX: 0000000000000102 RCX: ffff88805c810000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff8e4a882f R09: 1ffffffff1c95105
R10: dffffc0000000000 R11: fffffbfff1c95106 R12: ffffffff8cd834f0
R13: dffffc0000000000 R14: ffff8880b8e00000 R15: dffffc0000000000
FS:  00007fabb3d5c6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c336840 CR3: 0000000064951000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 interrupt_context_level include/linux/preempt.h:95 [inline]
 get_recursion_context kernel/events/internal.h:214 [inline]
 perf_swevent_get_recursion_context+0x7d/0x150 kernel/events/core.c:9946
 perf_trace_buf_alloc+0x59/0x290 kernel/trace/trace_event_perf.c:410
 perf_trace_preemptirq_template+0x14a/0x340 include/trace/events/preemptirq.h:14
 trace_irq_disable+0xbf/0xe0 include/trace/events/preemptirq.h:36
 irqentry_enter+0x3b/0x50 kernel/entry/common.c:381
 sysvec_irq_work+0xe/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:ffffc90000007740 EFLAGS: 00000206
RAX: e965b5ea806a4600 RBX: 1ffff92000000ef0 RCX: e965b5ea806a4600
RDX: dffffc0000000000 RSI: ffffffff8aaab9c0 RDI: ffffffff8afc66c0
RBP: ffffc90000007840 R08: ffffffff90da352f R09: 1ffffffff21b46a5
R10: dffffc0000000000 R11: fffffbfff21b46a6 R12: ffffffff8cd35400
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
 __rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:818 [inline]
 netif_receive_skb_list_internal+0x9ed/0xc60 net/core/dev.c:5831
 gro_normal_list include/net/gro.h:448 [inline]
 napi_complete_done+0x32a/0x810 net/core/dev.c:6170
 virtqueue_napi_complete drivers/net/virtio_net.c:450 [inline]
 virtnet_poll+0xa44/0x1180 drivers/net/virtio_net.c:2231
 __napi_poll+0xc0/0x460 net/core/dev.c:6600
 napi_poll net/core/dev.c:6667 [inline]
 net_rx_action+0x5ea/0xbf0 net/core/dev.c:6803
 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
 common_interrupt+0xb9/0xd0 arch/x86/kernel/irq.c:249
 </IRQ>
 <TASK>
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:678
RIP: 0010:finish_task_switch+0x26a/0x920 kernel/sched/core.c:5254
Code: 0f 84 37 01 00 00 48 85 db 0f 85 56 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 c0 a3 1a 09 e8 ab a2 2f 00 fb 4c 8b 65 c0 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc900036976b8 EFLAGS: 00000286
RAX: e965b5ea806a4600 RBX: 0000000000000000 RCX: e965b5ea806a4600
RDX: dffffc0000000000 RSI: ffffffff8aaab9c0 RDI: ffffffff8afc66c0
RBP: ffffc90003697710 R08: ffffffff90da352f R09: 1ffffffff21b46a5
R10: dffffc0000000000 R11: fffffbfff21b46a6 R12: ffff88805c810000
R13: dffffc0000000000 R14: ffff88805ec0da00 R15: ffff8880b8e3cf08
 context_switch kernel/sched/core.c:5383 [inline]
 __schedule+0x14da/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:PagePoisoned include/linux/page-flags.h:297 [inline]
RIP: 0010:page_to_nid include/linux/mm.h:1636 [inline]
RIP: 0010:folio_nid include/linux/mm.h:1642 [inline]
RIP: 0010:slab_nid mm/slab.h:208 [inline]
RIP: 0010:discard_slab+0x0/0x40 mm/slub.c:2121
Code: 48 02 84 c0 74 10 4d 89 77 08 4c 89 7b 10 4c 89 63 18 4d 89 34 24 5b 41 5c 41 5d 41 5e 41 5f 5d c3 0f 0b eb 92 0f 1f 44 00 00 <48> 8b 06 48 83 f8 ff 74 25 48 c1 e8 3a 0f b7 4e 2a 81 e1 ff 7f 00
RSP: 0018:ffffc90003697a98 EFLAGS: 00000246
RAX: e965b5ea806a4600 RBX: ffffea0000c61900 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: ffffea0000c61900 RDI: ffff888019a4cb40
RBP: ffff888019a4cb40 R08: ffffffff90da352f R09: 1ffffffff21b46a5
R10: dffffc0000000000 R11: fffffbfff21b46a6 R12: ffff888018258d80
R13: 0000000000100001 R14: 0000000000000a02 R15: ffff888018258d80
 __slab_free+0x35e/0x410 mm/slub.c:3722
 qlink_free mm/kasan/quarantine.c:166 [inline]
 qlist_free_all+0x75/0xe0 mm/kasan/quarantine.c:185
 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:305
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767
 slab_alloc_node mm/slub.c:3485 [inline]
 slab_alloc mm/slub.c:3493 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3500 [inline]
 kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3509
 kmem_cache_zalloc include/linux/slab.h:711 [inline]
 lsm_file_alloc security/security.c:612 [inline]
 security_file_alloc+0x34/0x120 security/security.c:2603
 init_file+0x94/0x1f0 fs/file_table.c:161
 alloc_empty_file+0xb7/0x1d0 fs/file_table.c:210
 alloc_file+0x5c/0x600 fs/file_table.c:293
 alloc_file_pseudo+0x17e/0x200 fs/file_table.c:336
 sock_alloc_file+0xb7/0x280 net/socket.c:469
 __sys_socketpair+0x2d0/0x550 net/socket.c:1802
 __do_sys_socketpair net/socket.c:1831 [inline]
 __se_sys_socketpair net/socket.c:1828 [inline]
 __x64_sys_socketpair+0x9b/0xb0 net/socket.c:1828
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fabb2f8ebe9
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:00007fabb3d5c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000035
RAX: ffffffffffffffda RBX: 00007fabb31b5fa0 RCX: 00007fabb2f8ebe9
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000001
RBP: 00007fabb3011e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000000180 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fabb31b6038 R14: 00007fabb31b5fa0 R15: 00007ffca588d708
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/25 21:34 linux-6.6.y bb9c90ab9c5a bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sock_alloc_file
* Struck through repros no longer work on HEAD.