================================================================== BUG: KASAN: use-after-free in batadv_interface_tx+0x1194/0x1880 net/batman-adv/soft-interface.c:226 Read of size 2 at addr ffff88809569634b by task syz-executor0/8571 CPU: 1 PID: 8571 Comm: syz-executor0 Not tainted 4.20.0+ #10 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 __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:00007f175e082c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000457ec9 RDX: 000000000000000e RSI: 0000000020000180 RDI: 0000000000000003 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f175e0836d4 R13: 00000000004c53f5 R14: 00000000004d8ef0 R15: 00000000ffffffff Allocated by task 8361: 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 __do_kmalloc_node mm/slab.c:3671 [inline] __kmalloc_node_track_caller+0x4e/0x70 mm/slab.c:3685 __kmalloc_reserve.isra.0+0x40/0xe0 net/core/skbuff.c:140 __alloc_skb+0x12d/0x730 net/core/skbuff.c:208 alloc_skb include/linux/skbuff.h:1011 [inline] __tcp_send_ack.part.0+0x6a/0x5b0 net/ipv4/tcp_output.c:3628 __tcp_send_ack net/ipv4/tcp_output.c:3655 [inline] tcp_send_ack+0x88/0xa0 net/ipv4/tcp_output.c:3655 tcp_cleanup_rbuf+0x246/0x790 net/ipv4/tcp.c:1585 tcp_recvmsg+0xa30/0x3270 net/ipv4/tcp.c:2163 inet_recvmsg+0x17b/0x6d0 net/ipv4/af_inet.c:830 sock_recvmsg_nosec net/socket.c:794 [inline] sock_recvmsg net/socket.c:801 [inline] sock_recvmsg+0xd0/0x110 net/socket.c:797 sock_read_iter+0x3ba/0x5a0 net/socket.c:878 call_read_iter include/linux/fs.h:1856 [inline] new_sync_read fs/read_write.c:406 [inline] __vfs_read+0x761/0xb20 fs/read_write.c:418 vfs_read+0x194/0x3e0 fs/read_write.c:452 ksys_read+0x105/0x260 fs/read_write.c:578 __do_sys_read fs/read_write.c:588 [inline] __se_sys_read fs/read_write.c:586 [inline] __x64_sys_read+0x73/0xb0 fs/read_write.c:586 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 8361: 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] kfree+0xcf/0x230 mm/slab.c:3804 skb_free_head+0x93/0xb0 net/core/skbuff.c:553 skb_release_data+0x6ea/0x970 net/core/skbuff.c:573 skb_release_all+0x4d/0x60 net/core/skbuff.c:627 __kfree_skb net/core/skbuff.c:641 [inline] consume_skb net/core/skbuff.c:701 [inline] consume_skb+0x18c/0x550 net/core/skbuff.c:695 __dev_kfree_skb_any+0xa4/0xd0 net/core/dev.c:2813 dev_consume_skb_any include/linux/netdevice.h:3591 [inline] free_old_xmit_skbs+0xca/0x200 drivers/net/virtio_net.c:1346 start_xmit+0x1b4/0x17c0 drivers/net/virtio_net.c:1517 __netdev_start_xmit include/linux/netdevice.h:4382 [inline] netdev_start_xmit include/linux/netdevice.h:4391 [inline] xmit_one net/core/dev.c:3278 [inline] dev_hard_start_xmit+0x261/0xc70 net/core/dev.c:3294 sch_direct_xmit+0x452/0x1100 net/sched/sch_generic.c:327 qdisc_restart net/sched/sch_generic.c:390 [inline] __qdisc_run+0x606/0x19d0 net/sched/sch_generic.c:398 qdisc_run include/net/pkt_sched.h:121 [inline] qdisc_run include/net/pkt_sched.h:118 [inline] __dev_xmit_skb net/core/dev.c:3473 [inline] __dev_queue_xmit+0x29d0/0x3a60 net/core/dev.c:3832 dev_queue_xmit+0x18/0x20 net/core/dev.c:3897 neigh_hh_output include/net/neighbour.h:498 [inline] neigh_output include/net/neighbour.h:506 [inline] ip_finish_output2+0x11f1/0x1a00 net/ipv4/ip_output.c:229 ip_finish_output+0x7e4/0xf60 net/ipv4/ip_output.c:317 NF_HOOK_COND include/linux/netfilter.h:278 [inline] ip_output+0x226/0x880 net/ipv4/ip_output.c:405 dst_output include/net/dst.h:444 [inline] ip_local_out+0xc4/0x1b0 net/ipv4/ip_output.c:124 __ip_queue_xmit+0x99a/0x1ee0 net/ipv4/ip_output.c:505 ip_queue_xmit+0x5a/0x70 include/net/ip.h:198 __tcp_transmit_skb+0x1add/0x3af0 net/ipv4/tcp_output.c:1160 __tcp_send_ack.part.0+0x3c6/0x5b0 net/ipv4/tcp_output.c:3649 __tcp_send_ack net/ipv4/tcp_output.c:3655 [inline] tcp_send_ack+0x88/0xa0 net/ipv4/tcp_output.c:3655 tcp_cleanup_rbuf+0x246/0x790 net/ipv4/tcp.c:1585 tcp_recvmsg+0xa30/0x3270 net/ipv4/tcp.c:2163 inet_recvmsg+0x17b/0x6d0 net/ipv4/af_inet.c:830 sock_recvmsg_nosec net/socket.c:794 [inline] sock_recvmsg net/socket.c:801 [inline] sock_recvmsg+0xd0/0x110 net/socket.c:797 sock_read_iter+0x3ba/0x5a0 net/socket.c:878 call_read_iter include/linux/fs.h:1856 [inline] new_sync_read fs/read_write.c:406 [inline] __vfs_read+0x761/0xb20 fs/read_write.c:418 vfs_read+0x194/0x3e0 fs/read_write.c:452 ksys_read+0x105/0x260 fs/read_write.c:578 __do_sys_read fs/read_write.c:588 [inline] __se_sys_read fs/read_write.c:586 [inline] __x64_sys_read+0x73/0xb0 fs/read_write.c:586 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff888095696000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 843 bytes inside of 1024-byte region [ffff888095696000, ffff888095696400) The buggy address belongs to the page: page:ffffea000255a580 count:1 mapcount:0 mapping:ffff88812c3f0ac0 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea0002558688 ffffea0002489888 ffff88812c3f0ac0 raw: 0000000000000000 ffff888095696000 0000000100000007 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888095696200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888095696280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888095696300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888095696380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888095696400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================