INFO: rcu detected stall in sys_recvmsg (2)

Status: upstream: reported on 2026/06/30 01:20
Reported-by: syzbot+15b85fcbb34e22a60cef@syzkaller.appspotmail.com
First crash: 34d, last: 34d
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in sys_recvmsg 1 6 1d09h 357d 0/3 upstream: reported on 2025/08/10 06:16
linux-6.1 INFO: rcu detected stall in sys_recvmsg 1 1 381d 381d 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 340d 340d 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 772d 859d 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 syz, C error 2 287d 467d 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 756d 835d 0/2 auto-obsoleted due to no activity on 2024/10/05 13:04

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-.... } 2651 jiffies s: 75877 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: 21208 Comm: syz.3.5314 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:check_region_inline mm/kasan/generic.c:172 [inline]
RIP: 0010:kasan_check_range+0x26/0x290 mm/kasan/generic.c:189
Code: 00 00 cc cc b0 01 48 85 f6 0f 84 ac 01 00 00 55 41 57 41 56 41 54 53 49 89 f8 49 01 f0 0f 82 0e 02 00 00 49 89 f8 49 c1 e8 2f <41> 81 f8 ff ff 01 00 0f 82 fa 01 00 00 49 bc 01 00 00 00 00 fc ff
RSP: 0018:ffffc90000006eb0 EFLAGS: 00000807
RAX: 0000000000000001 RBX: 000000000000002c RCX: ffffffff816406d9
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90af2240
RBP: ffffc90000007110 R08: 000000000001ffff R09: 1ffffffff215e448
R10: dffffc0000000000 R11: fffffbfff215e449 R12: ffff888027d0e578
R13: ffff888027d0da00 R14: ffff888027d0e558 R15: ffff888027d0e578
FS:  00007fcd99bd16c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1c4f3c9e9c CR3: 0000000076d30000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 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]
 __lock_acquire+0xdd9/0x7bd0 kernel/locking/lockdep.c:5019
 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]
 __perf_output_begin kernel/events/ring_buffer.c:163 [inline]
 perf_output_begin_forward+0xc3/0xa70 kernel/events/ring_buffer.c:272
 __perf_event_output kernel/events/core.c:7732 [inline]
 perf_event_output_forward+0x1ad/0x2f0 kernel/events/core.c:7750
 __perf_event_overflow+0x457/0x630 kernel/events/core.c:9496
 perf_swevent_overflow kernel/events/core.c:9579 [inline]
 perf_swevent_event+0x315/0x570 kernel/events/core.c:9630
 perf_tp_event+0x36b/0xc10 kernel/events/core.c:10064
 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10032
 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 82 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: 84dbaff511226500 RBX: 1ffff92000000f60 RCX: 84dbaff511226500
RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: ffffffff8adee1a0
RBP: ffffc90000007bc0 R08: ffffffff90af22ef R09: 1ffffffff215e45d
R10: dffffc0000000000 R11: fffffbfff215e45e R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8e3bb00 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 ieee80211_rx_napi+0x23d/0x3c0 net/mac80211/rx.c:5339
 ieee80211_rx include/net/mac80211.h:4849 [inline]
 ieee80211_handle_queued_frames+0x104/0x1a0 net/mac80211/main.c:317
 tasklet_action_common+0x2d0/0x460 kernel/softirq.c:827
 handle_softirqs+0x291/0x910 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:preempt_schedule_irq+0xb6/0x160 kernel/sched/core.c:6874
Code: 00 00 43 c6 44 37 04 f8 74 0b 0f 0b 48 f7 03 08 00 00 00 74 7f bf 01 00 00 00 e8 55 44 25 f7 e8 70 0f 55 f7 fb bf 01 00 00 00 <e8> 25 ba ff ff 43 c6 44 37 08 00 48 c7 44 24 40 00 00 00 00 9c 8f
RSP: 0018:ffffc9000c88f180 EFLAGS: 00000282
RAX: 84dbaff511226500 RBX: 0000000000000000 RCX: 84dbaff511226500
RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: 0000000000000001
RBP: ffffc9000c88f230 R08: ffffffff90af22ef R09: 1ffffffff215e45d
R10: dffffc0000000000 R11: fffffbfff215e45e R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff92001911e30
 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:lock_is_held_type+0x13a/0x190 kernel/locking/lockdep.c:5710
Code: 75 40 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 46 41 f7 c5 00 02 00 00 74 01 fb 65 48 8b 04 25 28 00 00 00 <48> 3b 44 24 08 75 3c 89 e8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f
RSP: 0018:ffffc9000c88f2f8 EFLAGS: 00000206
RAX: 84dbaff511226500 RBX: ffff888027d0da00 RCX: 84dbaff511226500
RDX: 0000000000000000 RSI: ffffffff8a8c2920 RDI: ffffffff8adee1a0
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff882bb6c0
R10: dffffc0000000000 R11: fffffbfff1c401ee R12: 0000000000000001
R13: 0000000000000246 R14: ffffffff8cb2dbc0 R15: ffff888027d0e508
 lock_is_held include/linux/lockdep.h:283 [inline]
 __might_resched+0x9b/0x5f0 kernel/sched/core.c:9931
 __might_fault+0x6d/0x120 mm/memory.c:5848
 _copy_to_iter+0xf8/0x1050 lib/iov_iter.c:526
 __skb_datagram_iter+0xde/0x740 net/core/datagram.c:419
 skb_copy_datagram_iter+0xd7/0x290 net/core/datagram.c:535
 skb_copy_datagram_msg include/linux/skbuff.h:4017 [inline]
 unix_stream_read_actor+0x68/0xa0 net/unix/af_unix.c:2971
 unix_stream_read_generic+0xcb1/0x1f50 net/unix/af_unix.c:2890
 unix_stream_recvmsg+0x165/0x1c0 net/unix/af_unix.c:3008
 ____sys_recvmsg+0x2c8/0x5b0 net/socket.c:-1
 ___sys_recvmsg+0x210/0x590 net/socket.c:2780
 __sys_recvmsg net/socket.c:2810 [inline]
 __do_sys_recvmsg net/socket.c:2820 [inline]
 __se_sys_recvmsg net/socket.c:2817 [inline]
 __x64_sys_recvmsg+0x20d/0x2e0 net/socket.c:2817
 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: 0033:0x7fcd98d9ce59
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:00007fcd99bd1028 EFLAGS: 00000246 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 00007fcd99015fa0 RCX: 00007fcd98d9ce59
RDX: 0000000040002002 RSI: 0000200000000000 RDI: 0000000000000005
RBP: 00007fcd98e32e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcd99016038 R14: 00007fcd99015fa0 R15: 00007ffc0628fcc8
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/30 01:19 linux-6.1.y fdb6fcb41cc7 6a0c72dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_recvmsg
* Struck through repros no longer work on HEAD.