syzbot

 sign-in | mailing list | source | docs
🐞 Open [831]
🐞 Fixed [87]
🐞 Invalid [1207]
⬇ Missing Backports [133]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
💬 Send us feedback

INFO: rcu detected stall in sys_recvmsg

Status: upstream: reported on 2025/08/10 06:16
Reported-by: syzbot+624e0eff6200cf7fb62e@syzkaller.appspotmail.com
First crash: 178d, last: 5d22h
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in sys_recvmsg 1 1 202d 202d 0/3 auto-obsoleted due to no activity on 2025/10/25 13:40
linux-6.6 INFO: rcu detected stall in sys_recvmsg 1 2 160d 161d 0/2 auto-obsoleted due to no activity on 2025/12/05 18:53
android-5-15 BUG: soft lockup in sys_recvmsg 1 10 592d 679d 0/2 auto-obsoleted due to no activity on 2024/09/19 17:52
android-5-10 BUG: soft lockup in sys_recvmsg (2) 1 C error 2 107d 287d 0/2 auto-obsoleted due to no activity on 2026/01/28 03:20
android-5-10 BUG: soft lockup in sys_recvmsg 1 4 577d 655d 0/2 auto-obsoleted due to no activity on 2024/10/05 13:04

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-....: (1 GPs behind) idle=03d/1/0x4000000000000002 softirq=141874/141875 fqs=5247 
	(detected by 1, t=10502 jiffies, g=195569, q=1253)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 18863 Comm: syz.1.16275 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:27 [inline]
RIP: 0010:static_key_false include/linux/jump_label.h:212 [inline]
RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:156 [inline]
RIP: 0010:wrmsr arch/x86/include/asm/msr.h:263 [inline]
RIP: 0010:native_apic_msr_write+0x35/0x50 arch/x86/include/asm/apic.h:208
Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 c3 89 f6 31 d2 e9 7f 39 d0 02 66 2e 0f 1f 84 00 00 00 00 00
RSP: 0018:ffffc90000007348 EFLAGS: 00000046
RAX: 00000000000000f6 RBX: ffffffff8be30a20 RCX: 000000000000083f
RDX: 0000000000000000 RSI: 00000000000000f6 RDI: 000000000000083f
RBP: 0000000000000000 R08: ffff8880b9033d77 R09: 1ffff110172067ae
R10: dffffc0000000000 R11: ffffed10172067af R12: 0000000000000000
R13: dffffc0000000001 R14: dffffc0000000000 R15: 0000000000000000
FS:  00007f3c72db66c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000009000 CR3: 00000000632c4000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 arch_irq_work_raise+0x82/0xd0 arch/x86/kernel/irq_work.c:31
 irq_work_queue_on+0x11e/0x220 kernel/irq_work.c:109
 rcu_read_unlock_special+0x37b/0x4a0 kernel/rcu/tree_plugin.h:667
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
 rcu_read_unlock include/linux/rcupdate.h:772 [inline]
 __perf_event_output kernel/events/core.c:7813 [inline]
 perf_event_output_forward+0x255/0x2e0 kernel/events/core.c:7822
 __perf_event_overflow+0x364/0x530 kernel/events/core.c:9515
 perf_tp_event+0x383/0xbf0 kernel/events/core.c:10047
 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021
 perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14
 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674
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 c2 ef 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc90000007b00 EFLAGS: 00000206
RAX: 1fa2c54f05472100 RBX: 1ffff92000000f64 RCX: 1fa2c54f05472100
RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f780
RBP: ffffc90000007bd8 R08: ffffffff901d1177 R09: 1ffffffff203a22e
R10: dffffc0000000000 R11: fffffbfff203a22f R12: ffffffff8c322f00
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
 rcu_read_unlock include/linux/rcupdate.h:772 [inline]
 ieee80211_iterate_active_interfaces_atomic+0x132/0x140 net/mac80211/util.c:831
 mac80211_hwsim_beacon+0x9b/0x180 drivers/net/wireless/mac80211_hwsim.c:1865
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4eb/0xb70 kernel/time/hrtimer.c:1749
 hrtimer_run_softirq+0x176/0x240 kernel/time/hrtimer.c:1766
 handle_softirqs+0x339/0x830 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:finish_lock_switch+0x134/0x280 kernel/sched/core.c:4804
Code: be ff ff ff ff e8 4c 80 67 08 85 c0 74 4a 4d 85 ff 75 66 0f 1f 44 00 00 48 89 df e8 b6 eb 70 08 e8 41 e0 2a 00 fb 48 83 c4 08 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 48 89 df e8 c9 09 fe ff 43 80 3c
RSP: 0018:ffffc9000329f328 EFLAGS: 00000286
RAX: 1fa2c54f05472100 RBX: ffff8880b903a340 RCX: 1fa2c54f05472100
RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f780
RBP: 1ffff11017207613 R08: ffffffff901d1177 R09: 1ffffffff203a22e
R10: dffffc0000000000 R11: fffffbfff203a22f R12: 1ffff110172075c1
R13: dffffc0000000000 R14: ffff8880b903ae08 R15: 0000000000000000
 finish_task_switch+0x12f/0x640 kernel/sched/core.c:4921
 context_switch kernel/sched/core.c:5052 [inline]
 __schedule+0x11f7/0x43c0 kernel/sched/core.c:6395
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799
 irqentry_exit+0x63/0x70 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:172 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:227 [inline]
RIP: 0010:__sanitizer_cov_trace_switch+0x5c/0xe0 kernel/kcov.c:329
Code: 41 54 53 48 8b 0c cd 48 e9 2e 8a 48 8b 54 24 20 65 4c 8b 05 76 4b 89 7e 45 31 c9 eb 08 49 ff c1 4c 39 c8 74 77 4e 8b 54 ce 10 <65> 44 8b 1d 64 4b 89 7e 41 81 e3 00 01 ff 00 74 13 41 81 fb 00 01
RSP: 0018:ffffc9000329f700 EFLAGS: 00000246
RAX: 0000000000000006 RBX: 0000000000000000 RCX: 0000000000000001
RDX: ffffffff83e1e316 RSI: ffffffff8c9224f0 RDI: 0000000000000000
RBP: 0000000000001000 R08: ffff88802c689dc0 R09: 0000000000000000
R10: 0000000000000000 R11: ffffed1009ae1200 R12: ffffea000135c240
R13: ffffc9000329fe58 R14: dffffc0000000000 R15: 0000000000000000
 __copy_page_to_iter lib/iov_iter.c:860 [inline]
 copy_page_to_iter+0x286/0x910 lib/iov_iter.c:889
 sk_msg_recvmsg+0x23a/0xc40 net/core/skmsg.c:438
 unix_bpf_recvmsg+0x519/0xd40 net/unix/unix_bpf.c:74
 ____sys_recvmsg+0x2cd/0x5e0 net/socket.c:-1
 ___sys_recvmsg+0x21a/0x5c0 net/socket.c:2706
 __sys_recvmsg net/socket.c:2736 [inline]
 __do_sys_recvmsg net/socket.c:2746 [inline]
 __se_sys_recvmsg net/socket.c:2743 [inline]
 __x64_sys_recvmsg+0x1f9/0x2c0 net/socket.c:2743
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f3c74b7beb9
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:00007f3c72db6028 EFLAGS: 00000246 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 00007f3c74df7090 RCX: 00007f3c74b7beb9
RDX: 0000000000000000 RSI: 00002000000004c0 RDI: 0000000000000003
RBP: 00007f3c74be9c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3c74df7128 R14: 00007f3c74df7090 R15: 00007fff94ce21a8
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/29 18:47 linux-5.15.y 9eec9a14ee10 aeb6fdd5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_recvmsg
2025/12/17 16:28 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_recvmsg
2025/09/18 07:13 linux-5.15.y 43bb85222e53 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_recvmsg
2025/08/10 06:15 linux-5.15.y c79648372d02 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_recvmsg
* Struck through repros no longer work on HEAD.