rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6303/1:b..l rcu: (detected by 0, t=10502 jiffies, g=19037, q=722 ncpus=2) task:syz-executor state:R running task stack:21736 pid:6303 ppid:6297 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6866 preempt_schedule+0xab/0xc0 kernel/sched/core.c:6890 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 vprintk_emit+0x578/0x600 kernel/printk/printk.c:2342 _printk+0xd0/0x110 kernel/printk/printk.c:2366 batadv_check_known_mac_addr+0x29b/0x3e0 net/batman-adv/hard-interface.c:526 batadv_hard_if_event+0x3a3/0x15b0 net/batman-adv/hard-interface.c:998 notifier_call_chain+0x197/0x390 kernel/notifier.c:93 call_netdevice_notifiers_extack net/core/dev.c:2064 [inline] call_netdevice_notifiers net/core/dev.c:2078 [inline] dev_set_mac_address+0x377/0x4b0 net/core/dev.c:8948 dev_set_mac_address_user+0x31/0x50 net/core/dev.c:8962 do_setlink+0x871/0x3fb0 net/core/rtnetlink.c:2860 __rtnl_newlink net/core/rtnetlink.c:3703 [inline] rtnl_newlink+0x175b/0x2020 net/core/rtnetlink.c:3750 rtnetlink_rcv_msg+0x7c7/0xf10 net/core/rtnetlink.c:6472 netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2545 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x46a/0x620 net/socket.c:2201 __do_sys_sendto net/socket.c:2213 [inline] __se_sys_sendto net/socket.c:2209 [inline] __x64_sys_sendto+0xde/0xf0 net/socket.c:2209 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f9abdd915dc RSP: 002b:00007ffc13fceec0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f9abeb14620 RCX: 00007f9abdd915dc RDX: 000000000000002c RSI: 00007f9abeb14670 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffc13fcef14 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f9abeb14670 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10547 jiffies! g19037 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:26920 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 schedule+0xbd/0x170 kernel/sched/core.c:6773 schedule_timeout+0x160/0x280 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x99/0x380 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 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 6303 Comm: syz-executor Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:vsnprintf+0x111/0x1a40 lib/vsprintf.c:2779 Code: 19 00 00 4c 63 f0 4b 8d 2c 37 48 8b 5c 24 40 0f b6 fb 48 c7 c6 80 41 32 8e e8 eb 6e 2d f7 0f b6 c3 83 f8 08 0f 8e ab 00 00 00 <83> f8 0c 49 be 00 00 00 00 00 fc ff df 0f 8e 3a 01 00 00 83 f8 0f RSP: 0018:ffffc90003066258 EFLAGS: 00000202 RAX: 000000000000000f RBX: ffff0a00ffffff0f RCX: 0000000000000001 RDX: ffffffff8a582695 RSI: ffffffff8e324180 RDI: 000000000000000f RBP: ffffffff8aab7e64 R08: ffff88802d038000 R09: 0000000000000012 R10: 0000000000000012 R11: 0000000000000000 R12: ffffc9000306642c R13: ffffc90003066421 R14: 0000000000000002 R15: ffffffff8aab7e62 FS: 0000555564c3c500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2e463fff CR3: 0000000075284000 CR4: 00000000003506e0 Call Trace: snprintf+0xdb/0x120 lib/vsprintf.c:2958 print_caller kernel/printk/printk.c:1336 [inline] info_print_prefix+0x1e2/0x300 kernel/printk/printk.c:1355 record_print_text+0x155/0x420 kernel/printk/printk.c:1402 printk_get_next_message+0x282/0x8e0 kernel/printk/printk.c:2876 console_emit_next_record kernel/printk/printk.c:2911 [inline] console_flush_all+0x3ad/0xd00 kernel/printk/printk.c:3000 console_unlock+0xae/0x340 kernel/printk/printk.c:3069 vprintk_emit+0x477/0x600 kernel/printk/printk.c:2341 _printk+0xd0/0x110 kernel/printk/printk.c:2366 batadv_check_known_mac_addr+0x29b/0x3e0 net/batman-adv/hard-interface.c:526 batadv_hard_if_event+0x3a3/0x15b0 net/batman-adv/hard-interface.c:998 notifier_call_chain+0x197/0x390 kernel/notifier.c:93 call_netdevice_notifiers_extack net/core/dev.c:2064 [inline] call_netdevice_notifiers net/core/dev.c:2078 [inline] dev_set_mac_address+0x377/0x4b0 net/core/dev.c:8948 dev_set_mac_address_user+0x31/0x50 net/core/dev.c:8962 do_setlink+0x871/0x3fb0 net/core/rtnetlink.c:2860 __rtnl_newlink net/core/rtnetlink.c:3703 [inline] rtnl_newlink+0x175b/0x2020 net/core/rtnetlink.c:3750 rtnetlink_rcv_msg+0x7c7/0xf10 net/core/rtnetlink.c:6472 netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2545 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x46a/0x620 net/socket.c:2201 __do_sys_sendto net/socket.c:2213 [inline] __se_sys_sendto net/socket.c:2209 [inline] __x64_sys_sendto+0xde/0xf0 net/socket.c:2209 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f9abdd915dc Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b RSP: 002b:00007ffc13fceec0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f9abeb14620 RCX: 00007f9abdd915dc RDX: 000000000000002c RSI: 00007f9abeb14670 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffc13fcef14 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f9abeb14670 R15: 0000000000000000