================================================================== BUG: KASAN: use-after-free in batadv_interface_tx+0xa45/0x14a0 net/batman-adv/soft-interface.c:227 Read of size 2 at addr ffff8880a123d34b by task syz-executor4/25078 CPU: 0 PID: 25078 Comm: syz-executor4 Not tainted 5.0.0-rc4+ #41 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+0x172/0x1f0 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+0xa45/0x14a0 net/batman-adv/soft-interface.c:227 __netdev_start_xmit include/linux/netdevice.h:4385 [inline] netdev_start_xmit include/linux/netdevice.h:4394 [inline] dev_direct_xmit+0x346/0x640 net/core/dev.c:3930 packet_direct_xmit+0xfb/0x170 net/packet/af_packet.c:246 packet_snd net/packet/af_packet.c:2933 [inline] packet_sendmsg+0x3879/0x5ab0 net/packet/af_packet.c:2958 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg+0xdd/0x130 net/socket.c:631 ___sys_sendmsg+0x3e2/0x930 net/socket.c:2116 __sys_sendmmsg+0x1c3/0x4e0 net/socket.c:2211 __do_sys_sendmmsg net/socket.c:2240 [inline] __se_sys_sendmmsg net/socket.c:2237 [inline] __x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2237 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457e39 Code: ad b8 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 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f699b411c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000457e39 RDX: 0000000000000001 RSI: 0000000020008a80 RDI: 0000000000000003 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f699b4126d4 R13: 00000000004c4d7a R14: 00000000004d8948 R15: 00000000ffffffff Allocated by task 24690: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_kmalloc mm/kasan/common.c:496 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:469 kasan_kmalloc mm/kasan/common.c:504 [inline] kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:411 kmem_cache_alloc+0x12d/0x710 mm/slab.c:3543 getname_kernel+0x53/0x370 fs/namei.c:220 call_usermodehelper_exec_async+0x5a7/0x740 kernel/umh.c:111 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Freed by task 24690: 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:458 kasan_slab_free+0xe/0x10 mm/kasan/common.c:466 __cache_free mm/slab.c:3487 [inline] kmem_cache_free+0x86/0x260 mm/slab.c:3749 putname+0xef/0x130 fs/namei.c:261 __do_execve_file.isra.0+0x1c08/0x23f0 fs/exec.c:1832 do_execveat_common fs/exec.c:1865 [inline] do_execve+0x33/0x40 fs/exec.c:1882 call_usermodehelper_exec_async+0x5b5/0x740 kernel/umh.c:111 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 The buggy address belongs to the object at ffff8880a123cbc0 which belongs to the cache names_cache of size 4096 The buggy address is located 1931 bytes inside of 4096-byte region [ffff8880a123cbc0, ffff8880a123dbc0) The buggy address belongs to the page: page:ffffea0002848f00 count:1 mapcount:0 mapping:ffff88821bc45380 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea00025d2988 ffffea0002604408 ffff88821bc45380 raw: 0000000000000000 ffff8880a123cbc0 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a123d200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a123d280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a123d300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a123d380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a123d400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================