rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P20852/1:b..l P64/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=103337, q=1939 ncpus=2)
task:kworker/u8:4 state:R running task stack:23008 pid:64 tgid:64 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: bat_events batadv_mcast_mla_update
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7190
irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x222/0x340 kernel/locking/lockdep.c:5872
Code: ff ff ff e8 70 d0 bb 09 f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 5a 1f e2 10 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 2a 50 72 ff cc 48 8d 3d 97 78 e7
RSP: 0018:ffffc9000213f378 EFLAGS: 00000286
RAX: ef39afbf67947400 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 00000000742e7d94 RSI: ffffffff8d976a88 RDI: ffffffff8bc086e0
RBP: ffffffff8173fdd5 R08: ffffffff8173fdd5 R09: ffffffff8df41aa0
R10: dffffc0000000000 R11: ffffffff81acf4d0 R12: 0000000000000002
R13: ffffffff8df41aa0 R14: 0000000000000000 R15: 0000000000000246
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+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495
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:6670 [inline]
kfree+0x1c0/0x660 mm/slub.c:6878
batadv_mcast_mla_list_free net/batman-adv/multicast.c:667 [inline]
__batadv_mcast_mla_update net/batman-adv/multicast.c:924 [inline]
batadv_mcast_mla_update+0x3293/0x3640 net/batman-adv/multicast.c:946
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
task:syz.0.4780 state:R running task stack:25312 pid:20852 tgid:20845 ppid:16339 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7190
irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:118 [inline]
RIP: 0010:lock_acquire+0x8b/0x340 kernel/locking/lockdep.c:5844
Code: 0f 84 cb 01 00 00 83 3d 82 65 e4 0d 00 0f 84 d4 00 00 00 48 8b b4 24 90 00 00 00 4c 89 ef e8 5c 01 89 00 83 3d 65 65 e4 0d 00 <0f> 84 cf 00 00 00 65 8b 05 68 66 e2 10 85 c0 0f 85 c0 00 00 00 65
RSP: 0018:ffffc9000217ec98 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000080000001
RDX: 0000000000000000 RSI: ffffffff8173fdf2 RDI: 1ffffffff1be8354
RBP: ffffffff8173fdd5 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff81acf4d0 R12: 0000000000000002
R13: ffffffff8df41aa0 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+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495
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
unpoison_slab_object mm/kasan/common.c:340 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4953 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
kmem_cache_alloc_node_noprof+0x43c/0x720 mm/slub.c:5315
kmalloc_reserve+0xbd/0x290 net/core/skbuff.c:586
__alloc_skb+0x204/0x3a0 net/core/skbuff.c:690
alloc_skb_fclone include/linux/skbuff.h:1433 [inline]
tcp_stream_alloc_skb+0x3d/0x350 net/ipv4/tcp.c:910
tso_fragment net/ipv4/tcp_output.c:2327 [inline]
tcp_write_xmit+0xd87/0x6980 net/ipv4/tcp_output.c:2988
__tcp_push_pending_frames+0x97/0x380 net/ipv4/tcp_output.c:3185
tcp_push_pending_frames include/net/tcp.h:2224 [inline]
tcp_data_snd_check net/ipv4/tcp_input.c:5896 [inline]
tcp_rcv_established+0xfe6/0x2580 net/ipv4/tcp_input.c:6476
tcp_v4_do_rcv+0xa90/0x1430 net/ipv4/tcp_ipv4.c:1881
sk_backlog_rcv include/net/sock.h:1177 [inline]
__release_sock+0x265/0x3a0 net/core/sock.c:3213
release_sock+0x5f/0x1f0 net/core/sock.c:3795
sk_stream_wait_memory+0x71f/0xf70 net/core/stream.c:149
tcp_sendmsg_locked+0x1dfb/0x5520 net/ipv4/tcp.c:1365
tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1412
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg+0x19c/0x270 net/socket.c:742
__sys_sendto+0x3bd/0x520 net/socket.c:2206
__do_sys_sendto net/socket.c:2213 [inline]
__se_sys_sendto net/socket.c:2209 [inline]
__x64_sys_sendto+0xde/0x100 net/socket.c:2209
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa4beb8f749
RSP: 002b:00007fa4bfa4a038 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007fa4bede6180 RCX: 00007fa4beb8f749
RDX: 000000000000fdef RSI: 0000200000000580 RDI: 0000000000000008
RBP: 00007fa4bec13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000010008095 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa4bede6218 R14: 00007fa4bede6180 R15: 00007ffcc0ab2018
rcu: rcu_preempt kthread starved for 10526 jiffies! g103337 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:27520 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
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+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 20851 Comm: syz.7.4781 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__might_sleep+0xb/0xf0 kernel/sched/core.c:8743
Code: 48 89 df e8 17 ef 94 00 e9 2f ff ff ff 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 41 57 41 56 41 55 <41> 54 53 50 49 bf 00 00 00 00 00 fc ff df 65 48 8b 1c 25 08 10 80
RSP: 0018:ffffc9000219f8c0 EFLAGS: 00000246
RAX: ffffffff820e8503 RBX: ffff888031d60000 RCX: 0000000000000002
RDX: ffff888031d60000 RSI: 00000000000000b5 RDI: ffffffff8d7ba4ee
RBP: 00000000000000b5 R08: ffff888031d60007 R09: 1ffff110063ac000
R10: dffffc0000000000 R11: ffffed10063ac001 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff8d7ba4ee R15: 0000000000000000
FS: 00007fd9211036c0(0000) GS:ffff888125f1f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f25ecdb7198 CR3: 000000003c135000 CR4: 0000000000350ef0
Call Trace:
__might_fault+0x77/0x130 mm/memory.c:7172
__clear_user arch/x86/include/asm/uaccess_64.h:181 [inline]
copy_fpstate_to_sigframe+0x13a/0xcc0 arch/x86/kernel/fpu/signal.c:203
get_sigframe+0x58d/0x7d0 arch/x86/kernel/signal.c:163
x64_setup_rt_frame+0x15b/0xd40 arch/x86/kernel/signal_64.c:175
setup_rt_frame arch/x86/kernel/signal.c:250 [inline]
handle_signal arch/x86/kernel/signal.c:294 [inline]
arch_do_signal_or_restart+0x3d1/0x7a0 arch/x86/kernel/signal.c:339
__exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
exit_to_user_mode_loop+0x87/0x4e0 kernel/entry/common.c:75
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x2c1/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd92018f747
Code: ff ff 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
RSP: 002b:00007fd921103038 EFLAGS: 00000246
RAX: 0000000000000048 RBX: 00007fd9203e5fa0 RCX: 00007fd92018f749
RDX: 0000200000000080 RSI: 0000000000000026 RDI: 0000000000000004
RBP: 00007fd920213f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd9203e6038 R14: 00007fd9203e5fa0 R15: 00007ffe44ff0ef8