syzbot


INFO: rcu detected stall in sendmsg (5)

Status: upstream: reported syz repro on 2025/06/23 07:43
Reported-by: syzbot+ddb3e33c76ab8ecb85a3@syzkaller.appspotmail.com
First crash: 231d, last: 1d07h
Bug presence (1)
Date Name Commit Repro Result
2025/09/10 upstream (ToT) 9dd1835ecda5 syz Didn't crash
Similar bugs (21)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in sendmsg (3) 1 4 495d 562d 0/3 auto-obsoleted due to no activity on 2025/01/09 18:13
upstream INFO: rcu detected stall in sendmsg net 1 1 1587d 1587d 0/29 auto-closed as invalid on 2022/01/03 17:11
linux-6.6 INFO: rcu detected stall in sendmsg 1 5 5d13h 192d 0/2 upstream: reported on 2025/07/31 17:16
linux-6.1 INFO: rcu detected stall in sendmsg (4) 1 2 335d 346d 0/3 auto-obsoleted due to no activity on 2025/06/19 03:57
linux-6.1 INFO: rcu detected stall in sendmsg (2) 1 1 685d 685d 0/3 auto-obsoleted due to no activity on 2024/07/04 03:49
upstream INFO: rcu detected stall in sendmsg (2) batman 1 1 1457d 1457d 0/29 auto-closed as invalid on 2022/05/13 12:25
upstream INFO: rcu detected stall in sendmsg (4) mm 1 C error 62 14d 626d 0/29 upstream: reported C repro on 2024/05/24 06:18
upstream INFO: rcu detected stall in sendmsg (3) net 1 4 734d 818d 0/29 auto-obsoleted due to no activity on 2024/05/05 18:15
linux-5.15 INFO: rcu detected stall in sys_sendmsg origin:upstream 1 C error 32 15d 691d 0/3 upstream: reported C repro on 2024/03/19 21:37
linux-6.1 INFO: rcu detected stall in sendmsg 1 1 919d 919d 0/3 auto-obsoleted due to no activity on 2023/11/12 19:28
upstream BUG: soft lockup in sys_sendmsg (2) net 1 C error 32 1d01h 249d 0/29 upstream: reported C repro on 2025/06/05 02:15
upstream INFO: rcu detected stall in sys_sendmsg (2) cgroups mm 1 5 2258d 2260d 0/29 closed as invalid on 2019/12/04 14:14
upstream INFO: rcu detected stall in sys_sendmsg (3) kernel 1 1 2224d 2224d 0/29 closed as invalid on 2020/01/08 05:33
linux-6.1 INFO: rcu detected stall in sys_sendmsg 1 6 498d 585d 0/3 auto-obsoleted due to no activity on 2025/01/06 11:24
upstream INFO: rcu detected stall in sys_sendmsg net 1 C done 2 2340d 2340d 13/29 fixed on 2019/10/09 10:54
android-6-1 BUG: soft lockup in sys_sendmsg origin:upstream 1 C 3 643d 671d 0/2 upstream: reported C repro on 2024/04/09 06:46
linux-6.1 BUG: soft lockup in sys_sendmsg 1 2 972d 978d 0/3 auto-obsoleted due to no activity on 2023/09/20 17:26
android-5-10 BUG: soft lockup in sys_sendmsg 1 C error 61 37d 688d 0/2 upstream: reported C repro on 2024/03/22 10:41
upstream BUG: soft lockup in sys_sendmsg tipc batman 1 C 3 686d 728d 25/29 fixed on 2024/05/22 23:36
android-5-15 BUG: soft lockup in sys_sendmsg origin:upstream 1 C error 13 515d 688d 0/2 upstream: reported C repro on 2024/03/22 10:44
linux-6.1 BUG: soft lockup in sys_sendmsg (2) origin:upstream 1 C done 1 673d 673d 3/3 fixed on 2024/05/15 09:17

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 1-.... } 2640 jiffies s: 257261 root: 0x2/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 13200 Comm: syz.4.14260 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:lockdep_hardirqs_on_prepare+0xd4/0x770 kernel/locking/lockdep.c:4296
Code: 82 6c 9e 7e 85 c0 0f 85 74 03 00 00 48 c7 c0 40 b1 bf 96 48 c1 e8 03 0f b6 04 10 84 c0 0f 85 18 05 00 00 83 3d 2c a7 5b 15 00 <75> 79 c6 44 13 04 00 48 c7 44 24 40 00 00 00 00 9c 8f 44 24 40 f7
RSP: 0018:ffffc900001e0920 EFLAGS: 00000046
RAX: 0000000000000004 RBX: 1ffff9200003c128 RCX: ffffffff96bfb103
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffffffff8cb74320
RBP: ffffc900001e09e0 R08: ffff8880b8f3580b R09: 1ffff110171e6b01
R10: dffffc0000000000 R11: ffffed10171e6b02 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007fdda06916c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056180cd16ad8 CR3: 00000000442f1000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000008d24 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 trace_hardirqs_on+0x34/0x40 kernel/trace/trace_preemptirq.c:49
 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 92 31 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:ffffc900001e0aa0 EFLAGS: 00000206
RAX: 4789f56c8b11d800 RBX: 1ffff9200003c15c RCX: 4789f56c8b11d800
RDX: dffffc0000000000 RSI: ffffffff8a8c1220 RDI: ffffffff8adf0d20
RBP: ffffc900001e0b90 R08: ffffffff90af4267 R09: 1ffffffff215e84c
R10: dffffc0000000000 R11: fffffbfff215e84d R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8f3b900 R15: 0000000000000002
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 ieee80211_iterate_active_interfaces_atomic+0x156/0x170 net/mac80211/util.c:826
 mac80211_hwsim_beacon+0xb7/0x1b0 drivers/net/wireless/mac80211_hwsim.c:2147
 __run_hrtimer kernel/time/hrtimer.c:1747 [inline]
 __hrtimer_run_queues+0x560/0xd70 kernel/time/hrtimer.c:1811
 hrtimer_run_softirq+0x183/0x2a0 kernel/time/hrtimer.c:1828
 handle_softirqs+0x2a1/0x930 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:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xbc/0x120 kernel/locking/spinlock.c:194
Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 0f 3c 22 f7 65 8b 05 d0 c0 cb 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc9000d967100 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000a02 RCX: 4789f56c8b11d800
RDX: dffffc0000000000 RSI: ffffffff8a8c1220 RDI: 0000000000000001
RBP: ffffc9000d967190 R08: ffffffff90af4267 R09: 1ffffffff215e84c
R10: dffffc0000000000 R11: fffffbfff215e84d R12: dffffc0000000000
R13: ffff888062fd0000 R14: ffffffff96f24bf8 R15: 1ffff92001b2ce20
 __debug_check_no_obj_freed lib/debugobjects.c:988 [inline]
 debug_check_no_obj_freed+0x515/0x530 lib/debugobjects.c:1009
 free_pages_prepare mm/page_alloc.c:1492 [inline]
 free_pcp_prepare mm/page_alloc.c:1536 [inline]
 free_unref_page_prepare+0x2a6/0x9a0 mm/page_alloc.c:3413
 free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3508
 free_slab mm/slub.c:2036 [inline]
 discard_slab mm/slub.c:2042 [inline]
 __unfreeze_partials+0x1a5/0x200 mm/slub.c:2591
 put_cpu_partial+0x17c/0x250 mm/slub.c:2667
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:294
 ____kasan_kmalloc mm/kasan/common.c:341 [inline]
 __kasan_kmalloc+0x1e/0xa0 mm/kasan/common.c:384
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __do_kmalloc_node mm/slab_common.c:936 [inline]
 __kmalloc+0xb0/0x240 mm/slab_common.c:949
 kmalloc_array include/linux/slab.h:615 [inline]
 genl_family_rcv_msg_attrs_parse+0xa3/0x290 net/netlink/genetlink.c:560
 genl_family_rcv_msg_doit+0xe5/0x330 net/netlink/genetlink.c:734
 genl_family_rcv_msg net/netlink/genetlink.c:833 [inline]
 genl_rcv_msg+0x604/0x790 net/netlink/genetlink.c:850
 netlink_rcv_skb+0x1fb/0x450 net/netlink/af_netlink.c:2511
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:861
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x74d/0x8d0 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x8ad/0xbd0 net/netlink/af_netlink.c:1872
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5be/0x970 net/socket.c:2518
 ___sys_sendmsg+0x2a2/0x360 net/socket.c:2572
 __sys_sendmsg net/socket.c:2601 [inline]
 __do_sys_sendmsg net/socket.c:2610 [inline]
 __se_sys_sendmsg+0x1bb/0x2a0 net/socket.c:2608
 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: 0033:0x7fdd9f79aeb9
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:00007fdda0691028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fdd9fa15fa0 RCX: 00007fdd9f79aeb9
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 000000000000000b
RBP: 00007fdd9f808c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdd9fa16038 R14: 00007fdd9fa15fa0 R15: 00007ffeded09898
 </TASK>

Crashes (12):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/08 02:45 linux-6.1.y 0182cb5b74ee 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sendmsg
2026/01/27 21:02 linux-6.1.y cd9b81672742 9a514c2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sendmsg
2026/01/02 08:25 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sendmsg
2025/11/28 08:26 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 sendmsg
2025/11/25 00:51 linux-6.1.y f6e38ae624cf bf6fe8fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sendmsg
2025/11/02 19:07 linux-6.1.y f6e38ae624cf 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sendmsg
2025/10/11 18:36 linux-6.1.y 882efbdd9d34 ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sendmsg
2025/10/05 15:40 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 sendmsg
2025/09/15 11:19 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 sendmsg
2025/09/09 11:16 linux-6.1.y 28c695c365e1 d291dd2d .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sendmsg
2025/07/31 15:32 linux-6.1.y 3594f306da12 f8f2b4da .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sendmsg
2025/06/23 07:42 linux-6.1.y 58485ff1a74f d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sendmsg
* Struck through repros no longer work on HEAD.