syzbot


INFO: rcu detected stall in sys_socket (3)

Status: upstream: reported C repro on 2025/09/09 01:58
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+6f9608a27846cc108b6b@syzkaller.appspotmail.com
First crash: 98d, last: 14d
Bug presence (2)
Date Name Commit Repro Result
2025/10/20 linux-6.1.y (ToT) 8e6e2188d949 C [report] INFO: rcu detected stall in sys_socket
2025/10/20 upstream (ToT) 211ddde0823f C Didn't crash
Similar bugs (16)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_socket (4) fs 1 1 1692d 1692d 0/29 auto-closed as invalid on 2021/07/27 17:27
linux-5.15 INFO: rcu detected stall in sys_socket 1 1 805d 805d 0/3 auto-obsoleted due to no activity on 2024/01/11 06:48
upstream INFO: rcu detected stall in sys_socket (5) net 1 2 1530d 1555d 0/29 auto-closed as invalid on 2022/01/06 01:08
upstream INFO: rcu detected stall in sys_socket mm 1 11 2204d 2205d 0/29 closed as invalid on 2019/12/04 14:04
linux-6.6 INFO: rcu detected stall in sys_socket 1 10 5d07h 157d 0/2 upstream: reported on 2025/07/12 12:18
linux-4.19 INFO: rcu detected stall in sys_socket 1 1 1334d 1334d 0/1 auto-closed as invalid on 2022/08/20 07:08
upstream INFO: rcu detected stall in sys_socket (10) mm 1 C done 175 2d00h 746d 0/29 upstream: reported C repro on 2023/11/30 15:24
linux-6.1 INFO: rcu detected stall in sys_socket 1 2 498d 498d 0/3 auto-obsoleted due to no activity on 2024/11/13 04:32
upstream INFO: rcu detected stall in sys_socket (6) cgroups mm 1 2 1189d 1233d 0/29 auto-obsoleted due to no activity on 2022/12/12 22:48
upstream INFO: rcu detected stall in sys_socket (7) kernel 1 2 1048d 1081d 0/29 auto-obsoleted due to no activity on 2023/05/02 14:50
linux-6.1 INFO: rcu detected stall in sys_socket (2) 1 3 287d 341d 0/3 auto-obsoleted due to no activity on 2025/06/11 16:02
upstream INFO: rcu detected stall in sys_socket (9) kasan mm 1 2 866d 875d 0/29 closed as invalid on 2023/09/07 14:25
upstream INFO: rcu detected stall in sys_socket (2) mm 1 3 2169d 2169d 0/29 closed as invalid on 2020/01/08 05:23
linux-5.15 INFO: rcu detected stall in sys_socket (2) origin:upstream 1 C error 27 6d14h 653d 0/3 upstream: reported C repro on 2024/03/02 17:55
upstream INFO: rcu detected stall in sys_socket (3) mm 1 4 2169d 2169d 0/29 closed as invalid on 2020/01/09 08:13
android-5-15 BUG: soft lockup in sys_socket 1 C error 26 465d 614d 0/2 auto-obsoleted due to no activity on 2024/11/29 22:24
Fix bisection attempts (1)
Created Duration User Patch Repo Result
2025/12/07 02:56 2h24m fix candidate upstream OK (0) job log

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-.... } 2690 jiffies s: 14849 root: 0x1/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 8736 Comm: syz.0.4054 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x4/0x60 kernel/kcov.c:215
Code: 00 00 00 00 00 90 53 48 89 fb e8 17 00 00 00 48 8b 3d 40 9b 9e 0c 48 89 de 5b e9 e7 64 4f 00 00 00 cc cc 00 00 cc 48 8b 04 24 <65> 48 8b 0d 54 a0 81 7e 65 8b 15 55 a0 81 7e 81 e2 00 01 ff 00 74
RSP: 0018:ffffc90000006fd8 EFLAGS: 00000046
RAX: ffffffff81a319c5 RBX: ffffc90000007180 RCX: ffff8880308a8000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900000070d0 R08: dffffc0000000000 R09: ffffc90000007120
R10: fffff52000000e2b R11: 1ffff92000000e24 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffffc90000007340
FS:  0000555593181500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000021c0 CR3: 0000000024afa000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 perf_prepare_sample+0xe05/0x2040 kernel/events/core.c:7633
 __perf_event_output kernel/events/core.c:7730 [inline]
 perf_event_output_forward+0x163/0x2a0 kernel/events/core.c:7750
 __perf_event_overflow+0x448/0x610 kernel/events/core.c:9496
 perf_swevent_overflow kernel/events/core.c:9572 [inline]
 perf_swevent_event+0x4ad/0x530 kernel/events/core.c:9610
 perf_tp_event+0x335/0xb60 kernel/events/core.c:10029
 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10002
 perf_trace_preemptirq_template+0x287/0x330 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+0x84/0x500 kernel/rcu/tree_plugin.h:685
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 3d 97 96 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:ffffc90000007760 EFLAGS: 00000206
RAX: e8d8c6e318d93600 RBX: 1ffff92000000ef4 RCX: e8d8c6e318d93600
RDX: dffffc0000000000 RSI: ffffffff8a8c0500 RDI: ffffffff8adef020
RBP: ffffc90000007860 R08: dffffc0000000000 R09: fffffbfff215c46a
R10: fffffbfff215c46a R11: 1ffffffff215c469 R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8e3b900 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 ndisc_send_skb+0xda7/0x1510 net/ipv6/ndisc.c:521
 addrconf_rs_timer+0x2b8/0x600 net/ipv6/addrconf.c:3979
 call_timer_fn+0x1a0/0x670 kernel/time/timer.c:1504
 expire_timers kernel/time/timer.c:1549 [inline]
 __run_timers+0x525/0x7c0 kernel/time/timer.c:1820
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833
 handle_softirqs+0x2a1/0x920 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x12f/0x220 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:preempt_schedule_irq+0xac/0x150 kernel/sched/core.c:6873
Code: 44 24 20 f6 44 24 21 02 74 0b 0f 0b 48 f7 03 08 00 00 00 74 70 bf 01 00 00 00 e8 5f 70 37 f7 e8 9a e6 66 f7 fb bf 01 00 00 00 <e8> df b9 ff ff 48 c7 44 24 40 00 00 00 00 9c 8f 44 24 40 8b 44 24
RSP: 0018:ffffc900057e7a20 EFLAGS: 00000282
RAX: e8d8c6e318d93600 RBX: 0000000000000000 RCX: e8d8c6e318d93600
RDX: dffffc0000000000 RSI: ffffffff8a8c0500 RDI: 0000000000000001
RBP: ffffc900057e7ad0 R08: dffffc0000000000 R09: ffffed10171c6afa
R10: ffffed10171c6afa R11: 1ffff110171c6af9 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff92000afcf44
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__kasan_check_read+0x0/0x10 mm/kasan/shadow.c:31
Code: 41 5c 41 5d 41 5e 41 5f 5d c3 48 c7 c7 31 74 5a 8c eb 0a 48 c7 c7 3c c7 43 8c 48 89 de e8 58 97 3b 08 31 ed eb d7 00 00 cc cc <89> f6 48 8b 0c 24 31 d2 e9 a3 ec ff ff 0f 1f 00 89 f6 48 8b 0c 24
RSP: 0018:ffffc900057e7b98 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e1f67e8
RBP: ffffc900057e7ca8 R08: 0000000000000001 R09: 0000000000000000
R10: ffffed100ace23dc R11: 1ffff1100ace23da R12: 0000000000000000
R13: 1ffff92000afcf80 R14: 0000000000000000 R15: dffffc0000000000
 instrument_atomic_read include/linux/instrumented.h:72 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 cpumask_test_cpu include/linux/cpumask.h:444 [inline]
 cpu_online include/linux/cpumask.h:1030 [inline]
 trace_lock_acquire include/trace/events/lock.h:24 [inline]
 lock_acquire+0xd9/0x490 kernel/locking/lockdep.c:5633
 fs_reclaim_acquire+0x94/0x100 mm/page_alloc.c:4736
 might_alloc include/linux/sched/mm.h:271 [inline]
 slab_pre_alloc_hook+0x2a/0x310 mm/slab.h:710
 slab_alloc_node mm/slub.c:3279 [inline]
 slab_alloc mm/slub.c:3367 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3374 [inline]
 kmem_cache_alloc+0x56/0x2f0 mm/slub.c:3383
 kmem_cache_zalloc include/linux/slab.h:689 [inline]
 lsm_inode_alloc security/security.c:596 [inline]
 security_inode_alloc+0x30/0x110 security/security.c:1040
 inode_init_always+0x8f8/0xc90 fs/inode.c:232
 alloc_inode fs/inode.c:268 [inline]
 new_inode_pseudo+0x91/0x1c0 fs/inode.c:1063
 sock_alloc net/socket.c:631 [inline]
 __sock_create+0x129/0x940 net/socket.c:1514
 sock_create net/socket.c:1606 [inline]
 __sys_socket_create net/socket.c:1643 [inline]
 __sys_socket+0xc4/0x190 net/socket.c:1671
 __do_sys_socket net/socket.c:1684 [inline]
 __se_sys_socket net/socket.c:1682 [inline]
 __x64_sys_socket+0x76/0x80 net/socket.c:1682
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc3ef78eec9
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:00007ffede6104a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 00007fc3ef9e5fa0 RCX: 00007fc3ef78eec9
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000010
RBP: 00007fc3ef811f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc3ef9e5fa0 R14: 00007fc3ef9e5fa0 R15: 0000000000000003
 </TASK>

Crashes (12):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/10/16 07:17 linux-6.1.y c2fda4b3f577 19568248 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_socket
2025/10/05 17:49 linux-6.1.y 882efbdd9d34 49379ee0 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_socket
2025/09/20 20:39 linux-6.1.y 363a599da6d9 67c37560 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_socket
2025/12/02 05:31 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_socket
2025/11/27 12:14 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_socket
2025/11/17 13:58 linux-6.1.y f6e38ae624cf ef766cd7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_socket
2025/11/11 16:21 linux-6.1.y f6e38ae624cf 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_socket
2025/11/11 13:44 linux-6.1.y f6e38ae624cf 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_socket
2025/10/06 08:00 linux-6.1.y 882efbdd9d34 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_socket
2025/09/13 22:33 linux-6.1.y 3db754f56897 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_socket
2025/09/12 16:54 linux-6.1.y 3db754f56897 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_socket
2025/09/09 01:57 linux-6.1.y 28c695c365e1 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_socket
* Struck through repros no longer work on HEAD.