netlink: 8 bytes leftover after parsing attributes in process `syz-executor.2'.
netlink: 8 bytes leftover after parsing attributes in process `syz-executor.2'.
==================================================================
BUG: KASAN: use-after-free in strcmp+0x7a/0xa0 lib/string.c:364
Read of size 1 at addr ffff888093013900 by task syz-executor.2/11797

CPU: 0 PID: 11797 Comm: syz-executor.2 Not tainted 5.8.0-rc3-syzkaller #0
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+0x1f0/0x31e lib/dump_stack.c:118
 print_address_description+0x66/0x5a0 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report+0x132/0x1d0 mm/kasan/report.c:530
 strcmp+0x7a/0xa0 lib/string.c:364
 devlink_get_from_attrs+0x171/0x2c0 net/core/devlink.c:133
 devlink_nl_cmd_region_read_dumpit+0x10e/0x1000 net/core/devlink.c:4271
 genl_lock_dumpit+0x86/0xa0 net/netlink/genetlink.c:575
 netlink_dump+0x4be/0x10d0 net/netlink/af_netlink.c:2245
 __netlink_dump_start+0x538/0x700 net/netlink/af_netlink.c:2353
 genl_family_rcv_msg_dumpit net/netlink/genetlink.c:638 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:733 [inline]
 genl_rcv_msg+0xb03/0xe00 net/netlink/genetlink.c:753
 netlink_rcv_skb+0x190/0x3a0 net/netlink/af_netlink.c:2469
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:764
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0x786/0x940 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0xa57/0xd70 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 ____sys_sendmsg+0x519/0x800 net/socket.c:2352
 ___sys_sendmsg net/socket.c:2406 [inline]
 __sys_sendmsg+0x2b1/0x360 net/socket.c:2439
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cb29
Code: Bad RIP value.
RSP: 002b:00007fb50828cc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004fe220 RCX: 000000000045cb29
RDX: 0000000000000000 RSI: 00000000200003c0 RDI: 0000000000000004
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000092e R14: 00000000004cc0c2 R15: 00007fb50828d6d4

Allocated by task 11806:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc+0x103/0x140 mm/kasan/common.c:494
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0xde/0x4f0 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1083 [inline]
 netlink_alloc_large_skb net/netlink/af_netlink.c:1175 [inline]
 netlink_sendmsg+0x7b2/0xd70 net/netlink/af_netlink.c:1893
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 ____sys_sendmsg+0x519/0x800 net/socket.c:2352
 ___sys_sendmsg net/socket.c:2406 [inline]
 __sys_sendmsg+0x2b1/0x360 net/socket.c:2439
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 11806:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0x114/0x170 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x220 mm/slab.c:3757
 skb_release_all net/core/skbuff.c:664 [inline]
 __kfree_skb+0x56/0x1c0 net/core/skbuff.c:678
 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
 netlink_unicast+0x78e/0x940 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0xa57/0xd70 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 ____sys_sendmsg+0x519/0x800 net/socket.c:2352
 ___sys_sendmsg net/socket.c:2406 [inline]
 __sys_sendmsg+0x2b1/0x360 net/socket.c:2439
 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff888093013800
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 256 bytes inside of
 1024-byte region [ffff888093013800, ffff888093013c00)
The buggy address belongs to the page:
page:ffffea00024c04c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00022e82c8 ffffea00025f7a48 ffff8880aa400c40
raw: 0000000000000000 ffff888093013000 0000000100000002 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888093013800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888093013880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888093013900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff888093013980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888093013a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================