IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready
8021q: adding VLAN 0 to HW filter on device batadv0
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BUG: KASAN: use-after-free in batadv_interface_tx+0x160a/0x18b0 net/batman-adv/soft-interface.c:226
Read of size 2 at addr ffff8880a638930b by task syz-executor057/8454

CPU: 1 PID: 8454 Comm: syz-executor057 Not tainted 4.20.0+ #394
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1d3/0x2c6 lib/dump_stack.c:113
 print_address_description.cold.5+0x9/0x1ff mm/kasan/report.c:187
 kasan_report.cold.6+0x1b/0x39 mm/kasan/report.c:317
 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/generic_report.c:145
 batadv_interface_tx+0x160a/0x18b0 net/batman-adv/soft-interface.c:226
 __netdev_start_xmit include/linux/netdevice.h:4382 [inline]
 netdev_start_xmit include/linux/netdevice.h:4391 [inline]
 dev_direct_xmit+0x36c/0x6a0 net/core/dev.c:3930
 packet_direct_xmit+0xfb/0x170 net/packet/af_packet.c:246
 packet_snd net/packet/af_packet.c:2932 [inline]
 packet_sendmsg+0x298a/0x6ad0 net/packet/af_packet.c:2957
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:631
 __sys_sendto+0x3d7/0x670 net/socket.c:1788
 __do_sys_sendto net/socket.c:1800 [inline]
 __se_sys_sendto net/socket.c:1796 [inline]
 __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1796
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441eb9
Code: e8 4c ad 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 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 0f 83 fb 04 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffe4a288b78 EFLAGS: 00000216 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441eb9
RDX: 000000000000000e RSI: 0000000020000180 RDI: 0000000000000003
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000216 R12: 0000000000000000
R13: 00000000004028d0 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 8340:
 save_stack+0x43/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 kasan_kmalloc+0xcb/0xd0 mm/kasan/common.c:482
 kasan_slab_alloc+0x12/0x20 mm/kasan/common.c:397
 kmem_cache_alloc_node+0x147/0x730 mm/slab.c:3631
 alloc_task_struct_node kernel/fork.c:158 [inline]
 dup_task_struct kernel/fork.c:849 [inline]
 copy_process+0x2027/0x8790 kernel/fork.c:1757
 _do_fork+0x1cb/0x11d0 kernel/fork.c:2222
 __do_sys_clone kernel/fork.c:2329 [inline]
 __se_sys_clone kernel/fork.c:2323 [inline]
 __x64_sys_clone+0xbf/0x150 kernel/fork.c:2323
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 8349:
 save_stack+0x43/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:444
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:452
 __cache_free mm/slab.c:3485 [inline]
 kmem_cache_free+0x83/0x290 mm/slab.c:3747
 free_task_struct kernel/fork.c:163 [inline]
 free_task+0x16e/0x1f0 kernel/fork.c:462
 __put_task_struct+0x2e6/0x620 kernel/fork.c:735
 put_task_struct include/linux/sched/task.h:96 [inline]
 delayed_put_task_struct+0x2ff/0x4c0 kernel/exit.c:181
 __rcu_reclaim kernel/rcu/rcu.h:240 [inline]
 rcu_do_batch kernel/rcu/tree.c:2452 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2773 [inline]
 rcu_process_callbacks+0xc5b/0x1600 kernel/rcu/tree.c:2754
 __do_softirq+0x30c/0xb2e kernel/softirq.c:292

The buggy address belongs to the object at ffff8880a63882c0
 which belongs to the cache task_struct of size 6080
The buggy address is located 4171 bytes inside of
 6080-byte region [ffff8880a63882c0, ffff8880a6389a80)
The buggy address belongs to the page:
page:ffffea000298e200 count:1 mapcount:0 mapping:ffff8880aa0fc900 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea00029fd308 ffffea0002369d08 ffff8880aa0fc900
raw: 0000000000000000 ffff8880a63882c0 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a6389200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a6389280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880a6389300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff8880a6389380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a6389400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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