* [syzbot] [batman?] INFO: rcu detected stall in batadv_iv_send_outstanding_bat_ogm_packet (6)
@ 2025-12-22 5:27 syzbot
2025-12-24 3:15 ` syzbot
0 siblings, 1 reply; 2+ messages in thread
From: syzbot @ 2025-12-22 5:27 UTC (permalink / raw)
To: antonio, b.a.t.m.a.n, davem, edumazet, horms, kuba, linux-kernel,
marek.lindner, netdev, pabeni, sven, sw, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: 516471569089 Merge tag 'libcrypto-fixes-for-linus' of git:..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10ead77c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=a11e0f726bfb6765
dashboard link: https://syzkaller.appspot.com/bug?extid=62348313fb96b25955aa
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=147f4d58580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5a94a2d04644/disk-51647156.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/31d4eeac4086/vmlinux-51647156.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e58508861b69/bzImage-51647156.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+62348313fb96b25955aa@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5953/1:b..l P3819/1:b..l P36/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=8897, q=377 ncpus=2)
task:kworker/u8:2 state:R running task stack:22840 pid:36 tgid:36 ppid:2 task_flags:0x24248060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-8:0)
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_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:cpu_max_bits_warn include/linux/cpumask.h:138 [inline]
RIP: 0010:cpumask_check include/linux/cpumask.h:145 [inline]
RIP: 0010:cpumask_test_cpu include/linux/cpumask.h:649 [inline]
RIP: 0010:cpu_online include/linux/cpumask.h:1231 [inline]
RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline]
RIP: 0010:lock_acquire+0x3b/0x330 kernel/locking/lockdep.c:5831
Code: 89 d5 41 54 45 89 c4 55 89 cd 53 48 89 fb 48 83 ec 38 65 48 8b 05 cd b4 18 12 48 89 44 24 30 31 c0 66 90 65 8b 05 e9 b4 18 12 <83> f8 07 0f 87 a2 02 00 00 89 c0 48 0f a3 05 72 b8 ee 0e 0f 82 74
RSP: 0018:ffffc90000ac66d0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff8e3c9620 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e3c9620
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000008490 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
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
kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
kasan_save_track+0x14/0x30 mm/kasan/common.c:77
unpoison_slab_object mm/kasan/common.c:339 [inline]
__kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:365
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]
kmem_cache_alloc_noprof+0x25e/0x770 mm/slub.c:5270
mempool_alloc_noprof+0x1b4/0x2f0 mm/mempool.c:567
bio_alloc_bioset+0x3de/0x8c0 block/bio.c:565
bio_alloc_clone block/bio.c:873 [inline]
bio_split+0x13b/0x440 block/bio.c:1711
bio_submit_split_bioset+0x31/0xa40 block/blk-merge.c:122
bio_submit_split+0xa8/0x160 block/blk-merge.c:152
__bio_split_to_limits block/blk.h:402 [inline]
blk_mq_submit_bio+0x67b/0x2c50 block/blk-mq.c:3184
__submit_bio+0x3cc/0x690 block/blk-core.c:637
__submit_bio_noacct_mq block/blk-core.c:724 [inline]
submit_bio_noacct_nocheck+0x53d/0xbe0 block/blk-core.c:755
submit_bio_noacct+0x5bd/0x1f40 block/blk-core.c:879
ext4_io_submit+0xa6/0x140 fs/ext4/page-io.c:404
ext4_do_writepages+0xe42/0x3c80 fs/ext4/inode.c:2952
ext4_writepages+0x37a/0x7d0 fs/ext4/inode.c:3026
do_writepages+0x27a/0x600 mm/page-writeback.c:2598
__writeback_single_inode+0x168/0x14a0 fs/fs-writeback.c:1737
writeback_sb_inodes+0x72e/0x1ce0 fs/fs-writeback.c:2030
__writeback_inodes_wb+0xf8/0x2d0 fs/fs-writeback.c:2107
wb_writeback+0x799/0xae0 fs/fs-writeback.c:2218
wb_check_old_data_flush fs/fs-writeback.c:2322 [inline]
wb_do_writeback fs/fs-writeback.c:2375 [inline]
wb_workfn+0x8a0/0xbb0 fs/fs-writeback.c:2403
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>
task:kworker/u8:14 state:R running task stack:25480 pid:3819 tgid:3819 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
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:lock_acquire+0x79/0x330 kernel/locking/lockdep.c:5872
Code: 82 74 02 00 00 8b 35 0a e9 ee 0e 85 f6 0f 85 8d 00 00 00 48 8b 44 24 30 65 48 2b 05 89 b4 18 12 0f 85 ad 02 00 00 48 83 c4 38 <5b> 5d 41 5c 41 5d 41 5e 41 5f e9 08 38 e1 09 65 8b 05 95 b4 18 12
RSP: 0018:ffffc9000d107a00 EFLAGS: 00000296
RAX: 0000000000000000 RBX: ffffffff8e3c9620 RCX: 0000000042e2d81e
RDX: 0000000000000000 RSI: ffffffff8daa7da3 RDI: ffffffff8bf2b380
RBP: 0000000000000002 R08: 000000007a5a0105 R09: 0000000057a5a010
R10: 0000000000000002 R11: ffff888033fc0b30 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:867 [inline]
batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:761 [inline]
batadv_iv_ogm_schedule_buff+0x5d0/0x14c0 net/batman-adv/bat_iv_ogm.c:833
batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:873 [inline]
batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:866 [inline]
batadv_iv_send_outstanding_bat_ogm_packet+0x329/0x920 net/batman-adv/bat_iv_ogm.c:1709
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>
task:udevd state:R running task stack:27112 pid:5953 tgid:5953 ppid:5190 task_flags:0x400140 flags:0x00080000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6863
preempt_schedule_notrace+0x62/0xe0 kernel/sched/core.c:7140
preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13
rcu_is_watching+0x8e/0xc0 kernel/rcu/tree.c:752
trace_lock_release include/trace/events/lock.h:69 [inline]
lock_release+0x201/0x2d0 kernel/locking/lockdep.c:5879
rcu_lock_release include/linux/rcupdate.h:341 [inline]
rcu_read_unlock include/linux/rcupdate.h:897 [inline]
class_rcu_destructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0x3f9/0x20b0 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
kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
kasan_save_track+0x14/0x30 mm/kasan/common.c:77
unpoison_slab_object mm/kasan/common.c:339 [inline]
__kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:365
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]
kmem_cache_alloc_noprof+0x25e/0x770 mm/slub.c:5270
lsm_file_alloc security/security.c:169 [inline]
security_file_alloc+0x34/0x2b0 security/security.c:2380
init_file+0x93/0x4c0 fs/file_table.c:159
alloc_empty_file+0x73/0x1e0 fs/file_table.c:241
path_openat+0xde/0x3140 fs/namei.c:4773
do_filp_open+0x20b/0x470 fs/namei.c:4814
do_sys_openat2+0x121/0x290 fs/open.c:1430
do_sys_open fs/open.c:1436 [inline]
__do_sys_openat fs/open.c:1452 [inline]
__se_sys_openat fs/open.c:1447 [inline]
__x64_sys_openat+0x174/0x210 fs/open.c:1447
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0d5b8a7407
RSP: 002b:00007ffee52231a0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f0d5c0b1880 RCX: 00007f0d5b8a7407
RDX: 0000000000080000 RSI: 0000559b925f46d0 RDI: ffffffffffffff9c
RBP: 0000559b925f46d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000009
</TASK>
rcu: rcu_preempt kthread starved for 10623 jiffies! g8897 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:28328 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
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6960
schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1ea/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: 6101 Comm: syz.1.30 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__lock_acquire+0x58/0x2890 kernel/locking/lockdep.c:5098
Code: 18 12 48 89 44 24 68 31 c0 85 db 0f 84 54 04 00 00 48 8b 07 49 89 fd 48 3d 00 86 b9 93 0f 84 42 04 00 00 44 8b 1d c8 b5 92 0c <45> 89 c7 89 f5 89 d3 45 89 c8 45 85 db 74 5d 48 3d 10 86 b9 93 74
RSP: 0018:ffffc90002fe78f8 EFLAGS: 00000006
RAX: ffffffff9ac2cf60 RBX: 0000000000000001 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888079e8d510
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: ffffc90002fe7bd8 R11: 0000000000000001 R12: ffff88802db2c980
R13: ffff888079e8d510 R14: 0000000000000000 R15: 0000000000000000
FS: 00007fa9d7eb66c0(0000) GS:ffff8881249f5000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa9d7eb5f98 CR3: 000000005b10e000 CR4: 00000000003526f0
Call Trace:
<TASK>
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825
__mutex_lock_common kernel/locking/mutex.c:614 [inline]
__mutex_lock+0x1aa/0x1ca0 kernel/locking/mutex.c:776
seccomp_do_user_notification.constprop.0+0xaa/0xe80 kernel/seccomp.c:1173
__seccomp_filter+0x8ea/0x11f0 kernel/seccomp.c:1338
__secure_computing+0x287/0x3b0 kernel/seccomp.c:1404
syscall_trace_enter+0x89/0x220 kernel/entry/syscall-common.c:44
syscall_enter_from_user_mode_work include/linux/entry-common.h:78 [inline]
syscall_enter_from_user_mode include/linux/entry-common.h:109 [inline]
do_syscall_64+0x42b/0xf80 arch/x86/entry/syscall_64.c:90
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa9d6f8f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa9d7eb60e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007fa9d71e5fa8 RCX: 00007fa9d6f8f749
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fa9d71e5fa8
RBP: 00007fa9d71e5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa9d71e6038 R14: 00007ffd414eed50 R15: 00007ffd414eee38
</TASK>
---
This report is generated by a bot. It may contain errors.
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If the report is already addressed, let syzbot know by replying with:
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If you want syzbot to run the reproducer, reply with:
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^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [syzbot] [batman?] INFO: rcu detected stall in batadv_iv_send_outstanding_bat_ogm_packet (6)
2025-12-22 5:27 [syzbot] [batman?] INFO: rcu detected stall in batadv_iv_send_outstanding_bat_ogm_packet (6) syzbot
@ 2025-12-24 3:15 ` syzbot
0 siblings, 0 replies; 2+ messages in thread
From: syzbot @ 2025-12-24 3:15 UTC (permalink / raw)
To: antonio, b.a.t.m.a.n, davem, edumazet, horms, kuba, linux-kernel,
marek.lindner, netdev, pabeni, sven, sw, syzkaller-bugs
syzbot has found a reproducer for the following issue on:
HEAD commit: cc3aa43b44bd Add linux-next specific files for 20251219
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=12b62022580000
kernel config: https://syzkaller.appspot.com/x/.config?x=da1bc82c6189c463
dashboard link: https://syzkaller.appspot.com/bug?extid=62348313fb96b25955aa
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12abdf1a580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=118eef1a580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/30bf539e6f28/disk-cc3aa43b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0e2f8b08e342/vmlinux-cc3aa43b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ec7ee6ece11f/bzImage-cc3aa43b.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+62348313fb96b25955aa@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P198/1:b..l P5961/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=13701, q=705 ncpus=2)
task:udevd state:R running task stack:24376 pid:5961 tgid:5961 ppid:5200 task_flags:0x400140 flags:0x00080000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5258 [inline]
__schedule+0x150e/0x5070 kernel/sched/core.c:6866
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193
irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_release+0x2a6/0x3b0 kernel/locking/lockdep.c:5893
Code: 4d 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 75 52 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 2a 0f 01 11 <48> 3b 44 24 28 75 75 48 83 c4 30 5b 41 5c 41 5d 41 5e 41 5f 5d e9
RSP: 0018:ffffc90003aa78b0 EFLAGS: 00000206
RAX: 6d71d4c1a37b0900 RBX: 0000000000000202 RCX: 6d71d4c1a37b0900
RDX: 0000000000000000 RSI: ffffffff8db7ed49 RDI: ffffffff8be07960
RBP: ffff88802e53a9b0 R08: ffffc90003aa7b20 R09: 0000000000000000
R10: ffffc90003aa7a38 R11: fffff52000754f49 R12: 0000000000000000
R13: 0000000000000000 R14: ffffffff8e13f2e0 R15: ffff88802e539e80
rcu_lock_release include/linux/rcupdate.h:341 [inline]
rcu_read_unlock include/linux/rcupdate.h:897 [inline]
class_rcu_destructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0x1ab1/0x23d0 arch/x86/kernel/unwind_orc.c:695
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2540 [inline]
slab_free mm/slub.c:6674 [inline]
kmem_cache_free+0x197/0x620 mm/slub.c:6785
do_readlinkat+0x293/0x500 fs/stat.c:596
__do_sys_readlink fs/stat.c:613 [inline]
__se_sys_readlink fs/stat.c:610 [inline]
__x64_sys_readlink+0x7f/0x90 fs/stat.c:610
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd103b153a7
RSP: 002b:00007ffefbfc23a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000059
RAX: ffffffffffffffda RBX: 00007ffefbfc2880 RCX: 00007fd103b153a7
RDX: 0000000000000400 RSI: 00007ffefbfc23b0 RDI: 00007ffefbfc2880
RBP: 00007ffefbfc23b0 R08: 000055a62739fc90 R09: 0000000000000020
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000400
R13: 00007ffefbfc30b5 R14: 000055a5fb7d0ca4 R15: 000055a5fb7d0bcc
</TASK>
task:kworker/u8:6 state:R running task stack:23512 pid:198 tgid:198 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5258 [inline]
__schedule+0x150e/0x5070 kernel/sched/core.c:6866
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193
irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x16c/0x340 kernel/locking/lockdep.c:5872
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 44 41 01 11 <48> 3b 44 24 58 0f 85 e5 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc900030177e0 EFLAGS: 00000206
RAX: 9c7a27e9643fc600 RBX: 0000000000000000 RCX: 9c7a27e9643fc600
RDX: 00000000814aee25 RSI: ffffffff8db7ed49 RDI: ffffffff8be07960
RBP: ffffffff8b269940 R08: ffffffff8b269940 R09: ffffffff8e13f2e0
R10: dffffc0000000000 R11: ffffed100f2f1517 R12: 0000000000000002
R13: ffffffff8e13f2e0 R14: 0000000000000000 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:867 [inline]
batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:761 [inline]
batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:833 [inline]
batadv_iv_ogm_schedule+0x454/0xf00 net/batman-adv/bat_iv_ogm.c:873
batadv_iv_send_outstanding_bat_ogm_packet+0x6c6/0x7e0 net/batman-adv/bat_iv_ogm.c:1709
process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279
process_scheduled_works kernel/workqueue.c:3362 [inline]
worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 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 10314 jiffies! g13701 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:27232 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5258 [inline]
__schedule+0x150e/0x5070 kernel/sched/core.c:6866
__schedule_loop kernel/sched/core.c:6948 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6963
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 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:
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+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: cc cc cc cc cc cc cc 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 33 9e 2a 00 f3 0f 1e fa fb f4 <e9> 48 ee 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6
RAX: af5d4f71fc268f00 RBX: ffffffff819786ba RCX: af5d4f71fc268f00
RDX: 0000000000000001 RSI: ffffffff8d997e54 RDI: ffffffff8be07960
RBP: ffffc90000197f10 R08: ffff8880b87336db R09: 1ffff110170e66db
R10: dffffc0000000000 R11: ffffed10170e66dc R12: ffffffff8fa22f70
R13: 1ffff11003adab70 R14: 0000000000000001 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff888125d25000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007efd7aea1f98 CR3: 0000000032c9a000 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+0x73/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x1ea/0x520 kernel/sched/idle.c:332
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430
start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
common_startup_64+0x13e/0x147
</TASK>
---
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2025-12-22 5:27 [syzbot] [batman?] INFO: rcu detected stall in batadv_iv_send_outstanding_bat_ogm_packet (6) syzbot
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