================================================================== BUG: KASAN: use-after-free in __ext4_check_dir_entry+0x2de/0x320 fs/ext4/dir.c:69 Read of size 2 at addr ffff8801b7231002 by task syz-executor0/9741 CPU: 0 PID: 9741 Comm: syz-executor0 Not tainted 4.16.0-rc7+ #9 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 print_address_description+0x73/0x250 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report+0x23c/0x360 mm/kasan/report.c:412 __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:431 __ext4_check_dir_entry+0x2de/0x320 fs/ext4/dir.c:69 ext4_readdir+0xd00/0x3600 fs/ext4/dir.c:237 iterate_dir+0x1ca/0x530 fs/readdir.c:51 SYSC_getdents64 fs/readdir.c:314 [inline] SyS_getdents64+0x221/0x420 fs/readdir.c:295 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x454e79 RSP: 002b:00007f2b08b70c68 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9 RAX: ffffffffffffffda RBX: 00007f2b08b716d4 RCX: 0000000000454e79 RDX: 00000000200015fc RSI: 0000000020001540 RDI: 0000000000000013 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000000a9 R14: 00000000006f3078 R15: 0000000000000000 Allocated by task 5133: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:552 __do_kmalloc_node mm/slab.c:3670 [inline] __kmalloc_node_track_caller+0x47/0x70 mm/slab.c:3684 __kmalloc_reserve.isra.39+0x41/0xd0 net/core/skbuff.c:137 __alloc_skb+0x13b/0x780 net/core/skbuff.c:205 alloc_skb include/linux/skbuff.h:983 [inline] nlmsg_new include/net/netlink.h:511 [inline] inet6_netconf_notify_devconf+0x9a/0x1a0 net/ipv6/addrconf.c:588 __addrconf_sysctl_register+0x31d/0x400 net/ipv6/addrconf.c:6437 addrconf_sysctl_register+0x116/0x1b0 net/ipv6/addrconf.c:6474 ipv6_add_dev+0xa3d/0x1310 net/ipv6/addrconf.c:459 ipv6_find_idev+0x1d4/0x250 net/ipv6/addrconf.c:495 addrconf_add_dev+0x29/0x180 net/ipv6/addrconf.c:2386 inet6_addr_add+0xa8/0x390 net/ipv6/addrconf.c:2839 inet6_rtm_newaddr+0x8d2/0xcf0 net/ipv6/addrconf.c:4617 rtnetlink_rcv_msg+0x57f/0xb10 net/core/rtnetlink.c:4635 netlink_rcv_skb+0x14b/0x380 net/netlink/af_netlink.c:2447 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4653 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline] netlink_unicast+0x4c4/0x6b0 net/netlink/af_netlink.c:1337 netlink_sendmsg+0xa4a/0xe60 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec net/socket.c:630 [inline] sock_sendmsg+0xca/0x110 net/socket.c:640 ___sys_sendmsg+0x767/0x8b0 net/socket.c:2046 __sys_sendmsg+0xe5/0x210 net/socket.c:2080 SYSC_sendmsg net/socket.c:2091 [inline] SyS_sendmsg+0x2d/0x50 net/socket.c:2087 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 5133: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527 __cache_free mm/slab.c:3486 [inline] kfree+0xd9/0x260 mm/slab.c:3801 skb_free_head+0x74/0xb0 net/core/skbuff.c:550 skb_release_data+0x58c/0x790 net/core/skbuff.c:570 skb_release_all+0x4a/0x60 net/core/skbuff.c:627 __kfree_skb net/core/skbuff.c:641 [inline] consume_skb+0x153/0x490 net/core/skbuff.c:701 netlink_broadcast_filtered+0x5d0/0x1360 net/netlink/af_netlink.c:1513 netlink_broadcast net/netlink/af_netlink.c:1535 [inline] nlmsg_multicast include/net/netlink.h:591 [inline] nlmsg_notify+0x91/0x150 net/netlink/af_netlink.c:2490 rtnl_notify+0xbb/0xe0 net/core/rtnetlink.c:713 inet6_netconf_notify_devconf+0x15e/0x1a0 net/ipv6/addrconf.c:600 __addrconf_sysctl_register+0x31d/0x400 net/ipv6/addrconf.c:6437 addrconf_sysctl_register+0x116/0x1b0 net/ipv6/addrconf.c:6474 ipv6_add_dev+0xa3d/0x1310 net/ipv6/addrconf.c:459 ipv6_find_idev+0x1d4/0x250 net/ipv6/addrconf.c:495 addrconf_add_dev+0x29/0x180 net/ipv6/addrconf.c:2386 inet6_addr_add+0xa8/0x390 net/ipv6/addrconf.c:2839 inet6_rtm_newaddr+0x8d2/0xcf0 net/ipv6/addrconf.c:4617 rtnetlink_rcv_msg+0x57f/0xb10 net/core/rtnetlink.c:4635 netlink_rcv_skb+0x14b/0x380 net/netlink/af_netlink.c:2447 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4653 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline] netlink_unicast+0x4c4/0x6b0 net/netlink/af_netlink.c:1337 netlink_sendmsg+0xa4a/0xe60 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec net/socket.c:630 [inline] sock_sendmsg+0xca/0x110 net/socket.c:640 ___sys_sendmsg+0x767/0x8b0 net/socket.c:2046 __sys_sendmsg+0xe5/0x210 net/socket.c:2080 SYSC_sendmsg net/socket.c:2091 [inline] SyS_sendmsg+0x2d/0x50 net/socket.c:2087 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff8801b7231000 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 2 bytes inside of 512-byte region [ffff8801b7231000, ffff8801b7231200) The buggy address belongs to the page: page:ffffea0006dc8c40 count:1 mapcount:0 mapping:ffff8801b7231000 index:0xffff8801b7231500 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffff8801b7231000 ffff8801b7231500 0000000100000002 raw: ffffea0006d8b5a0 ffffea0006d35be0 ffff8801dac00940 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801b7230f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8801b7230f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8801b7231000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801b7231080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801b7231100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================