batman_adv: batadv0: The MTU of interface batadv_slave_1 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1532 would solve the problem.
batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
------------[ cut here ]------------
WARNING: kernel/printk/printk_ringbuffer.c:1278 at get_data+0x48a/0x840 kernel/printk/printk_ringbuffer.c:1278, CPU#0: syz-executor/28716
Modules linked in:
CPU: 0 UID: 0 PID: 28716 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:get_data+0x48a/0x840 kernel/printk/printk_ringbuffer.c:1278
Code: 83 c4 f8 48 b8 00 00 00 00 00 fc ff df 41 0f b6 04 07 84 c0 0f 85 ee 01 00 00 44 89 65 00 49 83 c5 08 eb 13 e8 b7 d6 1e 00 90 <0f> 0b 90 eb 05 e8 ac d6 1e 00 45 31 ed 4c 89 e8 48 83 c4 28 5b 41
RSP: 0018:ffffc900039be4a0 EFLAGS: 00010293
RAX: ffffffff81a1ff09 RBX: 00003fffffffffff RCX: ffff888026e3bc80
RDX: 0000000000000000 RSI: 00003fffffffffff RDI: 0000000000000000
RBP: 0000000000000012 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000012
R13: 0000000000000000 R14: ffffc900039be5e8 R15: 1ffffffff1c4ab06
FS:  00005555864de500(0000) GS:ffff888125a9c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055557085c5c8 CR3: 00000000767aa000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 copy_data kernel/printk/printk_ringbuffer.c:1857 [inline]
 prb_read kernel/printk/printk_ringbuffer.c:1966 [inline]
 _prb_read_valid+0x672/0xa90 kernel/printk/printk_ringbuffer.c:2143
 prb_read_valid+0x3c/0x60 kernel/printk/printk_ringbuffer.c:2215
 printk_get_next_message+0x15c/0x7b0 kernel/printk/printk.c:2978
 console_emit_next_record kernel/printk/printk.c:3062 [inline]
 console_flush_one_record kernel/printk/printk.c:3194 [inline]
 console_flush_all+0x4cc/0xb10 kernel/printk/printk.c:3268
 __console_flush_and_unlock kernel/printk/printk.c:3298 [inline]
 console_unlock+0xbb/0x190 kernel/printk/printk.c:3338
 vprintk_emit+0x4c5/0x590 kernel/printk/printk.c:2423
 _printk+0xcf/0x120 kernel/printk/printk.c:2448
 netdev_info+0x10a/0x160 net/core/dev.c:12928
 __dev_set_promiscuity+0x307/0x740 net/core/dev.c:9500
 netif_set_promiscuity+0x50/0xe0 net/core/dev.c:9535
 dev_set_promiscuity+0x126/0x260 net/core/dev_api.c:287
 hsr_portdev_setup net/hsr/hsr_slave.c:155 [inline]
 hsr_add_port+0x5ce/0x980 net/hsr/hsr_slave.c:211
 hsr_dev_finalize+0x685/0xaa0 net/hsr/hsr_device.c:765
 hsr_newlink+0x8ad/0x9f0 net/hsr/hsr_netlink.c:128
 rtnl_newlink_create+0x310/0xb00 net/core/rtnetlink.c:3833
 __rtnl_newlink net/core/rtnetlink.c:3950 [inline]
 rtnl_newlink+0x16e4/0x1c80 net/core/rtnetlink.c:4065
 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6951
 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:746
 __sys_sendto+0x3bd/0x520 net/socket.c:2248
 __do_sys_sendto net/socket.c:2255 [inline]
 __se_sys_sendto net/socket.c:2251 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2251
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8356f90e5c
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:00007ffd9457f3e0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f8357d14620 RCX: 00007f8356f90e5c
RDX: 0000000000000048 RSI: 00007f8357d14670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffd9457f434 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f8357d14670 R15: 0000000000000000
 </TASK>