================================================================== BUG: KASAN: use-after-free in batadv_interface_tx+0x1194/0x1880 net/batman-adv/soft-interface.c:226 Read of size 2 at addr ffff88809739384b by task syz-executor5/31624 CPU: 0 PID: 31624 Comm: syz-executor5 Not tainted 4.20.0+ #8 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+0x1db/0x2d0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/generic_report.c:145 batadv_interface_tx+0x1194/0x1880 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+0x368/0x670 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+0x2753/0x6830 net/packet/af_packet.c:2957 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg+0xdd/0x130 net/socket.c:631 __sys_sendto+0x387/0x5f0 net/socket.c:1788 TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. __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+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457ec9 Code: 6d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fa8f601cc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000457ec9 RDX: 000000000000004c RSI: 0000000020000180 RDI: 000000000000000a RBP: 000000000073c040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa8f601d6d4 R13: 00000000004c5284 R14: 00000000004d8ba8 R15: 00000000ffffffff Allocated by task 29146: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] kasan_kmalloc mm/kasan/common.c:482 [inline] kasan_kmalloc+0xcf/0xe0 mm/kasan/common.c:455 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:397 kmem_cache_alloc+0x12d/0x710 mm/slab.c:3541 kmem_cache_zalloc include/linux/slab.h:730 [inline] __delayacct_tsk_init+0x20/0x80 kernel/delayacct.c:45 delayacct_tsk_init include/linux/delayacct.h:112 [inline] copy_process+0x410d/0x8730 kernel/fork.c:1803 _do_fork+0x1a9/0x1170 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+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 9: save_stack+0x45/0xd0 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+0x86/0x260 mm/slab.c:3747 delayacct_tsk_free include/linux/delayacct.h:121 [inline] __put_task_struct+0x1f4/0x630 kernel/fork.c:731 IPVS: set_ctl: invalid protocol: 44 172.20.20.187:20002 put_task_struct include/linux/sched/task.h:96 [inline] delayed_put_task_struct+0x2fd/0x4d0 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+0xc4a/0x1680 kernel/rcu/tree.c:2754 __do_softirq+0x30b/0xb11 kernel/softirq.c:292 IPVS: length: 27 != 24 The buggy address belongs to the object at ffff8880973937d0 which belongs to the cache task_delay_info(60:syz1) of size 136 The buggy address is located 123 bytes inside of 136-byte region [ffff8880973937d0, ffff888097393858) The buggy address belongs to the page: page:ffffea00025ce4c0 count:1 mapcount:0 mapping:ffff88808f049500 index:0xffff888097393898 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea0002166cc8 ffffea00022b9a48 ffff88808f049500 raw: ffff888097393898 ffff888097393000 0000000100000012 ffff888069432980 page dumped because: kasan: bad access detected IPVS: set_ctl: invalid protocol: 44 172.20.20.187:20002 page->mem_cgroup:ffff888069432980 Memory state around the buggy address: ffff888097393700: fc fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888097393780: fb fb fc fc fc fc fc fc fc fc fb fb fb fb fb fb >ffff888097393800: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc ^ ffff888097393880: fc fc fc fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888097393900: fb fb fb fb fc fc fc fc fc fc fc fc 00 00 00 00 ==================================================================