INFO: rcu detected stall in sctp_setsockopt (2)

Status: upstream: reported on 2026/05/28 16:14
Reported-by: syzbot+75f61b34664ddb3f1cd0@syzkaller.appspotmail.com
First crash: 59d, last: 9d07h
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in sctp_setsockopt 1 1 643d 643d 0/3 auto-obsoleted due to no activity on 2025/01/29 14:06
upstream INFO: rcu detected stall in sctp_setsockopt net 1 8 2508d 2715d 0/29 auto-closed as invalid on 2019/12/12 00:34
linux-4.19 INFO: rcu detected stall in sctp_setsockopt 1 3 2186d 2234d 0/1 auto-closed as invalid on 2020/11/28 08:55
upstream INFO: rcu detected stall in sctp_setsockopt (2) sctp 1 8 2156d 2294d 0/29 auto-closed as invalid on 2020/11/28 11:26
linux-6.1 INFO: rcu detected stall in sctp_setsockopt 1 1 85d 85d 0/3 upstream: reported on 2026/05/02 14:43

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-....: (1 GPs behind) idle=bbf/1/0x4000000000000000 softirq=34220/34221 fqs=2099 
	(detected by 1, t=10504 jiffies, g=47149, q=2021)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 13114 Comm: syz.4.1932 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
RIP: 0010:asm_sysvec_irq_work+0x0/0x20 arch/x86/include/asm/idtentry.h:707
Code: e9 a5 03 00 00 90 90 90 90 90 0f 01 ca fc 6a ff e8 a5 02 00 00 48 89 c4 48 89 e7 e8 3a ea de ff e9 85 03 00 00 90 90 90 90 90 <0f> 01 ca fc 6a ff e8 85 02 00 00 48 89 c4 48 89 e7 e8 0a ef de ff
RSP: 0018:ffffc90000007ad8 EFLAGS: 00000006
RAX: d2ba0d52578b2d00 RBX: 1ffff92000000f64 RCX: d2ba0d52578b2d00
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a2a40
RBP: ffffc90000007bd8 R08: ffffffff901e918f R09: 1ffffffff203d231
R10: dffffc0000000000 R11: fffffbfff203d232 R12: ffffffff8c323400
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
FS:  00007f2d014aa6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffda2190dc0 CR3: 0000000061a0c000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
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 22 9d 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
 __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+0x4ea/0xb60 kernel/time/hrtimer.c:1749
 hrtimer_run_softirq+0x176/0x240 kernel/time/hrtimer.c:1766
 handle_softirqs+0x336/0x830 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:stack_trace_consume_entry+0x9e/0x270 kernel/stacktrace.c:93
Code: cc 41 0f b6 04 17 84 c0 0f 85 73 01 00 00 44 89 23 b0 01 e9 99 00 00 00 31 c0 e9 92 00 00 00 48 89 f8 48 c1 e8 03 80 3c 10 00 <74> 29 49 89 ff 48 89 74 24 08 49 89 d4 4c 89 04 24 4c 89 cb e8 49
RSP: 0018:ffffc90002f1ee18 EFLAGS: 00000246
RAX: 1ffff920005e3de4 RBX: ffffc90002f1ef2c RCX: 0000000080000001
RDX: dffffc0000000000 RSI: ffffffff81bdf125 RDI: ffffc90002f1ef20
RBP: 1ffff920005e3de6 R08: ffffc90002f1ef30 R09: 0000000000000002
R10: dffffc0000000000 R11: fffff520005e3dd9 R12: 0000000000000000
R13: 1ffff920005e3de5 R14: ffffc90002f1ef28 R15: 1ffff920005e3de5
 arch_stack_walk+0x100/0x140 arch/x86/kernel/stacktrace.c:27
 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1710 [inline]
 slab_free_freelist_hook+0xec/0x170 mm/slub.c:1736
 slab_free mm/slub.c:3504 [inline]
 kmem_cache_free+0x8f/0x210 mm/slub.c:3520
 sctp_packet_pack net/sctp/output.c:512 [inline]
 sctp_packet_transmit+0x146f/0x28c0 net/sctp/output.c:620
 sctp_packet_singleton+0x22c/0x330 net/sctp/outqueue.c:780
 sctp_outq_flush_ctrl net/sctp/outqueue.c:911 [inline]
 sctp_outq_flush+0x4b6/0x3220 net/sctp/outqueue.c:1209
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1327 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1199 [inline]
 sctp_do_sm+0x129d/0x5610 net/sctp/sm_sideeffect.c:1170
 sctp_assoc_bh_rcv+0x3ee/0x630 net/sctp/associola.c:1054
 sctp_backlog_rcv+0x157/0x3b0 net/sctp/input.c:346
 sk_backlog_rcv include/net/sock.h:1080 [inline]
 __release_sock+0x1e6/0x460 net/core/sock.c:2731
 release_sock+0x5b/0x1b0 net/core/sock.c:3274
 sctp_wait_for_connect+0x389/0x6d0 net/sctp/socket.c:9369
 __sctp_connect+0xae3/0xd80 net/sctp/socket.c:1245
 __sctp_setsockopt_connectx net/sctp/socket.c:1334 [inline]
 sctp_setsockopt_connectx+0x101/0x1a0 net/sctp/socket.c:1361
 sctp_setsockopt+0x8eb/0xf80 net/sctp/socket.c:4624
 __sys_setsockopt+0x2bf/0x3d0 net/socket.c:2213
 __do_sys_setsockopt net/socket.c:2224 [inline]
 __se_sys_setsockopt net/socket.c:2221 [inline]
 __x64_sys_setsockopt+0xb1/0xc0 net/socket.c:2221
 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: 0033:0x7f2d03272e99
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:00007f2d014aa028 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007f2d034fb090 RCX: 00007f2d03272e99
RDX: 000000000000006e RSI: 0000000000000084 RDI: 0000000000000003
RBP: 00007f2d03308eaf R08: 000000000000001c R09: 0000000000000000
R10: 0000200000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2d034fb128 R14: 00007f2d034fb090 R15: 00007ffd0467e858
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/17 11:54 linux-5.15.y c86c4726e7f0 7f27c57a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sctp_setsockopt
2026/05/28 16:13 linux-5.15.y 241d66fa280c 681715f7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sctp_setsockopt
* Struck through repros no longer work on HEAD.