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: 259d, last: 2d01h
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 524d 591d 0/3 auto-obsoleted due to no activity on 2025/01/09 18:13
upstream INFO: rcu detected stall in sendmsg net 1 1 1616d 1616d 0/29 auto-closed as invalid on 2022/01/03 17:11
linux-6.6 INFO: rcu detected stall in sendmsg 1 6 5d22h 221d 0/2 upstream: reported on 2025/07/31 17:16
linux-6.1 INFO: rcu detected stall in sendmsg (4) 1 2 364d 374d 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 714d 714d 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 1486d 1486d 0/29 auto-closed as invalid on 2022/05/13 12:25
upstream INFO: rcu detected stall in sendmsg (4) mm 1 C error error 63 4d08h 655d 0/29 upstream: reported C repro on 2024/05/24 06:18
upstream INFO: rcu detected stall in sendmsg (3) net 1 4 763d 847d 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 35 7d11h 720d 0/3 upstream: reported C repro on 2024/03/19 21:37
linux-6.1 INFO: rcu detected stall in sendmsg 1 1 948d 948d 0/3 auto-obsoleted due to no activity on 2023/11/12 19:28
upstream BUG: soft lockup in sys_sendmsg (2) block 1 C error 39 3d07h 278d 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 2287d 2289d 0/29 closed as invalid on 2019/12/04 14:14
upstream INFO: rcu detected stall in sys_sendmsg (3) kernel 1 1 2253d 2253d 0/29 closed as invalid on 2020/01/08 05:33
linux-6.1 INFO: rcu detected stall in sys_sendmsg 1 6 527d 613d 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 2369d 2369d 13/29 fixed on 2019/10/09 10:54
android-6-1 BUG: soft lockup in sys_sendmsg origin:upstream 1 C 3 672d 699d 0/2 upstream: reported C repro on 2024/04/09 06:46
linux-6.1 BUG: soft lockup in sys_sendmsg 1 2 1001d 1007d 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 21d 717d 0/2 upstream: reported C repro on 2024/03/22 10:41
upstream BUG: soft lockup in sys_sendmsg tipc batman 1 C 3 715d 756d 25/29 fixed on 2024/05/22 23:36
android-5-15 BUG: soft lockup in sys_sendmsg origin:upstream 1 C error 13 544d 717d 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 702d 702d 3/3 fixed on 2024/05/15 09:17

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-.... } 2662 jiffies s: 35265 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: 10419 Comm: syz.0.1380 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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+0x84/0x290 mm/kasan/generic.c:189
Code: 49 c1 e9 03 4b 8d 1c 21 49 89 df 4d 29 df 49 83 ff 10 7f 29 4d 85 ff 0f 84 38 01 00 00 4c 89 cb 48 f7 d3 4c 01 f3 41 80 3b 00 <0f> 85 86 01 00 00 49 ff c3 48 ff c3 75 ee e9 18 01 00 00 44 89 dd
RSP: 0018:ffffc900000073d0 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffffffffffffffff RCX: ffffffff81645514
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90af6240
RBP: ffffc90000007650 R08: ffffffff90af6247 R09: 1ffffffff215ec48
R10: dffffc0000000000 R11: fffffbfff215ec48 R12: dffffc0000000001
R13: 00000000ad0db31b R14: 1ffffffff215ec48 R15: 0000000000000001
FS:  00007f31b72dc6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000057b59000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 instrument_atomic_read include/linux/instrumented.h:72 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 hlock_class kernel/locking/lockdep.c:228 [inline]
 __lock_acquire+0x12f4/0x7d10 kernel/locking/lockdep.c:5046
 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 trace_call_bpf+0xe0/0x6b0 kernel/trace/bpf_trace.c:134
 perf_trace_run_bpf_submit+0x79/0x1c0 kernel/events/core.c:9997
 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 e2 33 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:ffffc90000007ac0 EFLAGS: 00000206
RAX: 4a51554c15e42300 RBX: 1ffff92000000f60 RCX: 4a51554c15e42300
RDX: dffffc0000000000 RSI: ffffffff8a8c1220 RDI: ffffffff8adf0f60
RBP: ffffc90000007bb0 R08: ffffffff90af6267 R09: 1ffffffff215ec4c
R10: dffffc0000000000 R11: fffffbfff215ec4d 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]
 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+0x54a/0xd50 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 cc 21 f7 65 8b 05 d0 50 cb 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc900059f7120 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000a06 RCX: 4a51554c15e42300
RDX: dffffc0000000000 RSI: ffffffff8a8c1220 RDI: 0000000000000001
RBP: ffffc900059f71b0 R08: ffffffff90af6267 R09: 1ffffffff215ec4c
R10: dffffc0000000000 R11: fffffbfff215ec4d R12: dffffc0000000000
R13: ffff888050a80000 R14: ffffffff96e64b40 R15: 1ffff92000b3ee24
 __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_pages_ok+0x358/0xc40 mm/page_alloc.c:1742
 free_large_kmalloc+0xfd/0x190 mm/slab_common.c:913
 skb_free_head net/core/skbuff.c:762 [inline]
 skb_release_data+0x5db/0x7c0 net/core/skbuff.c:791
 skb_release_all net/core/skbuff.c:856 [inline]
 __kfree_skb net/core/skbuff.c:870 [inline]
 kfree_skb_reason+0x163/0x370 net/core/skbuff.c:893
 kfree_skb include/linux/skbuff.h:1252 [inline]
 netlink_attachskb+0x914/0xb40 net/netlink/af_netlink.c:1232
 netlink_unicast+0x263/0x8d0 net/netlink/af_netlink.c:1353
 nlmsg_unicast include/net/netlink.h:1088 [inline]
 netlink_ack+0xcdd/0x1170 net/netlink/af_netlink.c:2473
 netlink_rcv_skb+0x280/0x450 net/netlink/af_netlink.c:2517
 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: 0033:0x7f31b639c799
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:00007f31b72dc028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f31b6615fa0 RCX: 00007f31b639c799
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 000000000000000f
RBP: 00007f31b6432bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f31b6616038 R14: 00007f31b6615fa0 R15: 00007ffd3f571328
 </TASK>

Crashes (15):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/08 05:25 linux-6.1.y f2ddafa93a25 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sendmsg
2026/03/01 01:06 linux-6.1.y 779f9571ac3e 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sendmsg
2026/02/10 06:47 linux-6.1.y 0182cb5b74ee 4ab09a02 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sendmsg
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.