INFO: rcu detected stall in sys

Date	Name	Commit	Repro	Result
2026/02/21	linux-6.6.y (ToT)	7a137e9bfa0e	C	[report] INFO: rcu detected stall in corrupted
2026/02/21	upstream (ToT)	d79526b89571	C	Didn't crash

Date

Name

Commit

Repro

Result

2026/02/21

linux-6.6.y (ToT)

7a137e9bfa0e

[report] INFO: rcu detected stall in corrupted

2026/02/21

upstream (ToT)

d79526b89571

Didn't crash

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	INFO: rcu detected stall in sys_sendto (2) mm	1				93	2254d	2254d	0/29	closed as dup on 2020/01/08 06:15
upstream	INFO: rcu detected stall in sys_sendto (6) net	1				1	838d	838d	0/29	closed as invalid on 2024/02/01 10:31
linux-6.1	INFO: rcu detected stall in sys_sendto origin:upstream	1	C		error	1	551d	774d	0/3	auto-obsoleted due to no activity on 2025/10/30 02:21
linux-5.15	INFO: rcu detected stall in sys_sendto	1				1	574d	574d	0/3	auto-obsoleted due to no activity on 2024/11/22 09:09
upstream	INFO: rcu detected stall in sys_sendto mm	1				357	2289d	2290d	0/29	closed as invalid on 2019/12/04 14:14
upstream	INFO: rcu detected stall in sys_sendto (7) mm	1	C	error	error	346	4d21h	658d	0/29	upstream: reported C repro on 2024/05/21 18:44
upstream	INFO: rcu detected stall in sys_sendto (5) perf	1				7	1500d	1621d	0/29	closed as invalid on 2022/02/08 10:00
upstream	INFO: rcu detected stall in sys_sendto (4) perf	1				1	2079d	2079d	0/29	auto-closed as invalid on 2020/09/29 07:17
linux-5.15	INFO: rcu detected stall in sys_sendto (2) origin:lts-only	1	syz		done	2	373d	465d	0/3	upstream: reported syz repro on 2024/12/01 03:42
upstream	INFO: rcu detected stall in sys_sendto (3) kernel	1				1	2157d	2157d	0/29	closed as invalid on 2020/05/21 18:32
linux-6.1	INFO: rcu detected stall in sys_sendto (2) origin:upstream	1	syz		error	1	88d	88d	0/3	upstream: reported syz repro on 2025/12/12 19:08
android-5-10	BUG: soft lockup in sys_sendto	1				2	938d	974d	0/2	auto-obsoleted due to no activity on 2023/11/14 13:19
android-5-15	BUG: soft lockup in sys_sendto	1				1	630d	630d	0/2	auto-obsoleted due to no activity on 2024/09/16 21:53

Created	Duration	User	Patch	Repo	Result
2026/02/21 21:29	0m	fix candidate		upstream	error job log

Created

Duration

User

Patch

Repo

Result

2026/02/21 21:29

fix candidate

upstream

error job log

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5885/1:b..l P5139/1:b..l rcu: (detected by 1, t=10502 jiffies, g=12497, q=531 ncpus=2) task:udevd state:R running task stack:25160 pid:5139 ppid:1 flags:0x00004002 Call Trace: <TASK> context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x111/0x120 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] __wake_up_common_lock kernel/sched/wait.c:140 [inline] __wake_up_sync_key+0x12c/0x1a0 kernel/sched/wait.c:213 sock_def_readable+0x1e1/0x420 net/core/sock.c:3354 __netlink_sendskb net/netlink/af_netlink.c:1266 [inline] netlink_sendskb+0x9b/0x130 net/netlink/af_netlink.c:1272 netlink_sendmsg+0x8d0/0xbf0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x5ba/0x960 net/socket.c:2594 ___sys_sendmsg+0x2a6/0x360 net/socket.c:2648 __sys_sendmsg net/socket.c:2677 [inline] __do_sys_sendmsg net/socket.c:2686 [inline] __se_sys_sendmsg+0x1c2/0x2b0 net/socket.c:2684 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f92e6ea7407 RSP: 002b:00007ffea3cb6dc0 EFLAGS: 00000202 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f92e7578880 RCX: 00007f92e6ea7407 RDX: 0000000000000000 RSI: 00007ffea3cb6e20 RDI: 0000000000000004 RBP: 0000555aa5eccab0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00000000000000b3 R13: 0000555aa5e579e0 R14: 0000000000000000 R15: 0000000000000000 </TASK> task:syz-executor state:R running task stack:21704 pid:5885 ppid:5883 flags:0x00004002 Call Trace: <TASK> context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:ipv6_store_devconf net/ipv6/addrconf.c:5637 [inline] RIP: 0010:inet6_fill_ifla6_attrs+0x522/0x21f0 net/ipv6/addrconf.c:5816 Code: 8d bd 04 06 00 00 4c 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 0f 85 98 10 00 00 49 63 3f e8 36 21 3b f8 4d 8d bc 24 b0 00 00 00 <4c> 89 f9 48 c1 e9 03 42 0f b6 0c 31 84 c9 0f 85 92 10 00 00 41 89 RSP: 0018:ffffc900036e6980 EFLAGS: 00000202 RAX: 000000000036ee80 RBX: 00000000ffffffff RCX: ffff888023f33c00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000057e40 RBP: ffffc900036e6aa0 R08: ffff88807db50413 R09: 0000000000000000 R10: ffff88807db50328 R11: ffffed100fb6a083 R12: ffff88807db50324 R13: ffff8880771a6000 R14: dffffc0000000000 R15: ffff88807db503d4 inet6_fill_link_af+0x9b/0x120 net/ipv6/addrconf.c:5862 rtnl_fill_link_af+0x1c2/0x430 net/core/rtnetlink.c:1701 rtnl_fill_ifinfo+0x1bb6/0x1e50 net/core/rtnetlink.c:1931 rtmsg_ifinfo_build_skb+0x18e/0x260 net/core/rtnetlink.c:4072 rtmsg_ifinfo_event net/core/rtnetlink.c:4106 [inline] rtmsg_ifinfo+0x8c/0x1a0 net/core/rtnetlink.c:4115 register_netdevice+0x17b8/0x1bb0 net/core/dev.c:10340 cfg80211_register_netdevice+0x159/0x2f0 net/wireless/core.c:1457 ieee80211_if_add+0xa1b/0x14e0 net/mac80211/iface.c:2270 ieee80211_register_hw+0x35ca/0x4250 net/mac80211/main.c:1441 mac80211_hwsim_new_radio+0x2a00/0x4d10 drivers/net/wireless/virtual/mac80211_hwsim.c:5307 hwsim_new_radio_nl+0xdc9/0x1a90 drivers/net/wireless/virtual/mac80211_hwsim.c:5988 genl_family_rcv_msg_doit+0x211/0x310 net/netlink/genetlink.c:971 genl_family_rcv_msg net/netlink/genetlink.c:1051 [inline] genl_rcv_msg+0x619/0x7a0 net/netlink/genetlink.c:1066 netlink_rcv_skb+0x241/0x4d0 net/netlink/af_netlink.c:2545 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1075 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8d0/0xbf0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x4a9/0x6b0 net/socket.c:2200 __do_sys_sendto net/socket.c:2212 [inline] __se_sys_sendto net/socket.c:2208 [inline] __x64_sys_sendto+0xde/0xf0 net/socket.c:2208 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fb34955cece RSP: 002b:00007ffe9d4ffb38 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 000055555bba5500 RCX: 00007fb34955cece RDX: 0000000000000024 RSI: 00007fb34a344670 RDI: 0000000000000003 RBP: 0000000000000001 R08: 00007ffe9d4ffbb4 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 0000000000000000 R14: 00007fb34a344670 R15: 0000000000000000 </TASK> rcu: rcu_preempt kthread starved for 10583 jiffies! g12497 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:27656 pid:17 ppid:2 flags:0x00004000 Call Trace: <TASK> context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 </TASK> rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5754 Comm: kworker/0:3 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Workqueue: events nsim_fib_event_work RIP: 0010:__debug_check_no_obj_freed lib/debugobjects.c:-1 [inline] RIP: 0010:debug_check_no_obj_freed+0x1e6/0x540 lib/debugobjects.c:1020 Code: 0f 84 40 03 00 00 49 89 ee 49 c1 ee 03 41 80 3c 16 00 74 12 48 89 ef e8 38 a1 ae fd 48 ba 00 00 00 00 00 fc ff df 48 8b 45 00 <48> 89 04 24 4c 8d 7d 18 4c 89 f8 48 c1 e8 03 80 3c 10 00 74 12 4c RSP: 0018:ffffc900046af4f0 EFLAGS: 00000046 RAX: ffff88802e0bb3b8 RBX: 0000000000000000 RCX: 0000000000000001 RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffffc900046af3e0 RBP: ffff8880605e4dc8 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff520008d5e7c R12: ffff88807a9d8000 R13: ffff88807a9d0000 R14: 1ffff1100c0bc9b9 R15: 0000000000000004 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000006b000 CR3: 000000002c609000 CR4: 00000000003506f0 Call Trace: <TASK> free_pages_prepare mm/page_alloc.c:1187 [inline] free_unref_page_prepare+0x1da/0x8c0 mm/page_alloc.c:2365 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2458 __slab_free+0x35a/0x400 mm/slub.c:3736 qlink_free mm/kasan/quarantine.c:166 [inline] qlist_free_all+0x75/0xd0 mm/kasan/quarantine.c:185 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:306 kasan_slab_alloc include/linux/kasan.h:188 [inline] slab_post_alloc_hook+0x6e/0x4b0 mm/slab.h:767 slab_alloc_node mm/slub.c:3495 [inline] __kmem_cache_alloc_node+0x13a/0x250 mm/slub.c:3534 kmalloc_trace+0x2a/0xe0 mm/slab_common.c:1098 kmalloc include/linux/slab.h:600 [inline] kzalloc include/linux/slab.h:721 [inline] nsim_fib6_rt_create drivers/net/netdevsim/fib.c:547 [inline] nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline] nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline] nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline] nsim_fib_event_work+0x1123/0x31b0 drivers/net/netdevsim/fib.c:1494 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2711 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 </TASK>

Crashes (5):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2026/02/21 13:12	linux-6.6.y	7a137e9bfa0e	6e7b5511	.config	console log	report	syz / log	C		[disk image] [vmlinux] [kernel image]	ci2-linux-6-6-kasan	INFO: rcu detected stall in sys_sendto
2026/01/05 10:17	linux-6.6.y	5fa4793a2d2d	d6526ea3	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci2-linux-6-6-kasan-perf	INFO: rcu detected stall in sys_sendto
2025/12/18 05:01	linux-6.6.y	5fa4793a2d2d	d6526ea3	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci2-linux-6-6-kasan-perf	INFO: rcu detected stall in sys_sendto
2025/10/01 01:54	linux-6.6.y	147338df3487	65a0eece	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci2-linux-6-6-kasan	INFO: rcu detected stall in sys_sendto
2025/08/26 10:53	linux-6.6.y	bb9c90ab9c5a	bf27483f	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci2-linux-6-6-kasan	INFO: rcu detected stall in sys_sendto

Crashes (5):

Assets (help?)