INFO: rcu detected stall in batadv_mcast_mla

ID	Workflow	Result	Correct	Bug	Created	Started	Finished	Revision	Error
023e4879	patching		💥	INFO: rcu detected stall in batadv_mcast_mla_update (2)	2026/07/09 10:21	2026/07/09 10:21	2026/07/09 11:02	93f57954	reproducer did not crash
47a3e4c5	assessment-security	DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌	❓	INFO: rcu detected stall in batadv_mcast_mla_update (2)	2026/05/25 02:35	2026/05/25 02:35	2026/05/25 03:37	c69befb3

Title	Replies (including bot)	Last reply
[syzbot] Monthly batman report (Dec 2025)	0 (1)	2025/12/22 13:07
[syzbot] [batman?] INFO: rcu detected stall in batadv_mcast_mla_update (2)	0 (1)	2025/12/22 05:27

Title

Replies (including bot)

Last reply

[syzbot] Monthly batman report (Dec 2025)

0 (1)

2025/12/22 13:07

[syzbot] [batman?] INFO: rcu detected stall in batadv_mcast_mla_update (2)

0 (1)

2025/12/22 05:27

Kernel	Title	Rank 🛈	Count	Last	Reported	Patched	Status
linux-5.15	INFO: rcu detected stall in batadv_mcast_mla_update	1	1	517d	517d	0/3	auto-obsoleted due to no activity on 2025/06/04 18:56
upstream	INFO: rcu detected stall in batadv_mcast_mla_update batman	1	6	669d	765d	0/29	auto-obsoleted due to no activity on 2024/12/24 16:54
linux-5.15	INFO: rcu detected stall in batadv_mcast_mla_update (2)	1	4	137d	330d	0/3	auto-obsoleted due to no activity on 2026/06/19 20:10

Rank 🛈

linux-5.15

INFO: rcu detected stall in batadv_mcast_mla_update

517d

0/3

auto-obsoleted due to no activity on 2025/06/04 18:56

upstream

INFO: rcu detected stall in batadv_mcast_mla_update batman

669d

765d

0/29

auto-obsoleted due to no activity on 2024/12/24 16:54

linux-5.15

INFO: rcu detected stall in batadv_mcast_mla_update (2)

137d

330d

0/3

auto-obsoleted due to no activity on 2026/06/19 20:10

Created	Duration	User	Repo	Result
2026/06/24 08:56	25m	retest repro	upstream	log
2026/04/14 20:11	1h40m	retest repro	upstream	report log
2026/01/18 15:43	21m	retest repro	upstream	report log
2026/01/18 12:21	40m	retest repro	linux-next	OK log

Created

Duration

User

Patch

Repo

Result

2026/06/24 08:56

25m

retest repro

upstream

log

2026/04/14 20:11

1h40m

retest repro

upstream

report log

2026/01/18 15:43

21m

retest repro

upstream

report log

2026/01/18 12:21

40m

retest repro

linux-next

OK log

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4912/1:b..l rcu: (detected by 0, t=10503 jiffies, g=9721, q=383 ncpus=2) task:kworker/u8:16 state:R running task stack:25480 pid:4912 tgid:4912 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: bat_events batadv_mcast_mla_update Call Trace: <TASK> context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__update_cpu_freelist_fast mm/slub.c:4385 [inline] RIP: 0010:__slab_alloc_node mm/slub.c:4873 [inline] RIP: 0010:slab_alloc_node mm/slub.c:5251 [inline] RIP: 0010:__kmalloc_cache_noprof+0x4de/0x800 mm/slub.c:5771 Code: c9 74 b9 48 85 db 75 a9 eb b2 4d 85 c9 74 ad 48 85 db 74 a8 bf ff ff ff ff 41 8b 44 24 40 49 8b 34 24 48 8d 4a 08 49 8b 1c 01 <4c> 89 c8 65 48 0f c7 0e 0f 85 51 ff ff ff 41 8b 44 24 40 0f 0d 0c RSP: 0018:ffffc9000ebe79a0 EFLAGS: 00000246 RAX: 0000000000000010 RBX: ffff8880792c5a00 RCX: 000000000010c861 RDX: 000000000010c859 RSI: ffffffff93b4a250 RDI: 00000000ffffffff RBP: ffffc9000ebe7a00 R08: 0000000000000018 R09: ffff8880792c5840 R10: 0000000000000000 R11: ffff888036e5aff0 R12: ffff88813ff26780 R13: 0000000000000820 R14: 00000000aaff3300 R15: 0000000000000018 kmalloc_noprof include/linux/slab.h:957 [inline] batadv_mcast_mla_meshif_get_ipv6 net/batman-adv/multicast.c:475 [inline] batadv_mcast_mla_meshif_get net/batman-adv/multicast.c:533 [inline] __batadv_mcast_mla_update net/batman-adv/multicast.c:909 [inline] batadv_mcast_mla_update+0x1937/0x31b0 net/batman-adv/multicast.c:946 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 </TASK> rcu: rcu_preempt kthread starved for 9521 jiffies! g9721 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 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:28440 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: <TASK> context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:7047 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x61/0x80 kernel/locking/spinlock.c:194 rcu_gp_fqs_loop+0x216/0xaf0 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 </TASK> rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 5905 Comm: kworker/u9:3 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: hci4 hci_conn_timeout RIP: 0010:restore_regs_and_return_to_kernel+0x10/0x2e Code: ef 3f 48 81 cf 00 08 00 00 48 81 cf 00 10 00 00 0f 22 df 58 5f e9 6e ff ff ff f6 84 24 88 00 00 00 03 74 02 0f 0b 41 5f 41 5e <41> 5d 41 5c 5d 5b 41 5b 41 5a 41 59 41 58 58 59 5a 5e 5f 48 83 c4 RSP: 0018:ffffc9000469f4c8 EFLAGS: 00000046 RAX: 00000000000f1699 RBX: 0000000000000000 RCX: 0000000000000007 RDX: 0000000000000000 RSI: ffffffff8dacde18 RDI: ffffffff8bf2b380 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff9088b3d7 R11: ffff8880265f8b30 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881249f5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000058 CR3: 000000005b778000 CR4: 00000000003526f0 Call Trace: <TASK> RIP: 0010:rcu_is_watching+0x80/0xc0 kernel/rcu/tree.c:752 Code: 89 da 48 c1 ea 03 0f b6 14 02 48 89 d8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 24 8b 03 c1 e8 02 83 e0 01 65 ff 0d 30 9e 0f 12 <74> 07 5b 5d e9 97 21 d8 09 e8 e2 f4 88 ff 5b 5d e9 8b 21 d8 09 48 RSP: 0018:ffffc9000469f560 EFLAGS: 00000286 RAX: 0000000000000001 RBX: ffff8880b85339e8 RCX: 0000000000000002 RDX: 0000000000000000 RSI: ffffffff8bf2b300 RDI: ffffffff8dd7bf28 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 00000000000128d3 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0x2cd/0x330 kernel/locking/lockdep.c:5831 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xd1/0x20b0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x160/0x1f0 mm/page_owner.c:165 __reset_page_owner+0x84/0x1a0 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0x7df/0x1170 mm/page_alloc.c:2943 discard_slab mm/slub.c:3346 [inline] __put_partials+0x130/0x170 mm/slub.c:3886 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4c/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:349 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] __kmalloc_cache_noprof+0x282/0x800 mm/slub.c:5771 kmalloc_noprof include/linux/slab.h:957 [inline] hci_cmd_sync_submit+0xbc/0x330 net/bluetooth/hci_sync.c:714 hci_cmd_sync_run+0x93/0xf0 net/bluetooth/hci_sync.c:807 hci_cmd_sync_run_once+0x1b5/0x200 net/bluetooth/hci_sync.c:823 hci_abort_conn+0x182/0x360 net/bluetooth/hci_conn.c:3004 hci_conn_timeout+0x1f3/0x230 net/bluetooth/hci_conn.c:579 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 </TASK> NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: c6 5f 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 13 49 12 00 fb f4 <e9> cc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc90000197de8 EFLAGS: 000002c6 RAX: 00000000000725eb RBX: 0000000000000001 RCX: ffffffff8b7816d9 RDX: 0000000000000000 RSI: ffffffff8dacde18 RDI: ffffffff8bf2b380 RBP: ffffed1003b58498 R08: 0000000000000001 R09: ffffed10170a673d R10: ffff8880b85339eb R11: ffff88801dac2ff0 R12: 0000000000000001 R13: ffff88801dac24c0 R14: ffffffff9088b3d0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881249f5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa8c8f2a6b0 CR3: 00000000650ec000 CR4: 00000000003526f0 Call Trace: <TASK> arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x38d/0x510 kernel/sched/idle.c:332 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x148 </TASK>

Crashes (7):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2025/12/20 18:55	upstream	dd9b004b7ff3	d6526ea3	.config	console log	report	syz / log	C		[disk image] [vmlinux] [kernel image]	ci-upstream-kasan-gce-selinux-root	INFO: rcu detected stall in batadv_mcast_mla_update
2025/12/25 17:42	upstream	ccd1cdca5cd4	d6526ea3	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci-upstream-kasan-gce-selinux-root	INFO: rcu detected stall in batadv_mcast_mla_update
2026/02/11 10:29	linux-next	fd9678829d6d	441e25b7	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci-upstream-linux-next-kasan-gce-root	INFO: rcu detected stall in batadv_mcast_mla_update
2026/01/04 11:54	linux-next	cc3aa43b44bd	d6526ea3	.config	console log	report	syz / log			[disk image] [vmlinux] [kernel image]	ci-upstream-linux-next-kasan-gce-root	INFO: rcu detected stall in batadv_mcast_mla_update
2025/12/24 10:09	linux-next	cc3aa43b44bd	d6526ea3	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci-upstream-linux-next-kasan-gce-root	INFO: rcu detected stall in batadv_mcast_mla_update
2025/12/21 13:29	linux-next	cc3aa43b44bd	d6526ea3	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci-upstream-linux-next-kasan-gce-root	INFO: rcu detected stall in batadv_mcast_mla_update
2025/11/25 03:17	linux-next	422f3140bbcb	64219f15	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci-upstream-linux-next-kasan-gce-root	INFO: rcu detected stall in batadv_mcast_mla_update

Crashes (7):

Assets (help?)