==================================================================
BUG: KASAN: slab-use-after-free in __ethtool_get_link_ksettings+0x6e/0x190
Read of size 8 at addr ffff88802e7a42e8 by task syz.6.851/8955

CPU: 1 UID: 0 PID: 8955 Comm: syz.6.851 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 print_report+0xca/0x240
 kasan_report+0x118/0x150
 __ethtool_get_link_ksettings+0x6e/0x190
 ib_get_eth_speed+0x15e/0x7b0
 rxe_query_port+0x93/0x3b0
 ib_query_port+0x170/0x830
 fill_port_info+0x1b9/0x5b0
 nldev_port_get_dumpit+0x57f/0x8a0
 netlink_dump+0x6e4/0xe90
 __netlink_dump_start+0x5cb/0x7e0
 rdma_nl_rcv+0x749/0x980
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x505/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __x64_sys_sendmsg+0x19b/0x260
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f43f158ec29
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f43ef7f6038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f43f17d5fa0 RCX: 00007f43f158ec29
RDX: 0000000000000000 RSI: 0000200000000480 RDI: 000000000000000e
RBP: 00007f43f1611e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f43f17d6038 R14: 00007f43f17d5fa0 R15: 00007ffd5f099398
 </TASK>

Allocated by task 8020:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kvmalloc_node_noprof+0x30d/0x5f0
 seq_read_iter+0x1fd/0xe10
 vfs_read+0x55a/0xa30
 ksys_read+0x145/0x250
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 8020:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5b/0x80
 kfree+0x18e/0x440
 seq_release+0x54/0x70
 kernfs_fop_release+0x133/0x190
 __fput+0x44c/0xa70
 fput_close_sync+0x119/0x200
 __x64_sys_close+0x7f/0x110
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88802e7a4000
 which belongs to the cache kmalloc-cg-4k of size 4096
The buggy address is located 744 bytes inside of
 freed 4096-byte region [ffff88802e7a4000, ffff88802e7a5000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2e7a0
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888023eb9741
anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801a44b500 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000040004 00000000f5000000 ffff888023eb9741
head: 00fff00000000040 ffff88801a44b500 0000000000000000 dead000000000001
head: 0000000000000000 0000000000040004 00000000f5000000 ffff888023eb9741
head: 00fff00000000003 ffffea0000b9e801 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5842, tgid 5842 (syz-executor), ts 55824358878, free_ts 0
 post_alloc_hook+0x240/0x2a0
 get_page_from_freelist+0x21e4/0x22c0
 __alloc_frozen_pages_noprof+0x181/0x370
 alloc_pages_mpol+0x232/0x4a0
 allocate_slab+0x8a/0x370
 ___slab_alloc+0xbeb/0x1420
 __kmalloc_node_track_caller_noprof+0x2f8/0x4e0
 kmemdup_noprof+0x2b/0x70
 __addrconf_sysctl_register+0x9e/0x4c0
 addrconf_sysctl_register+0x168/0x1c0
 ipv6_add_dev+0xd46/0x1370
 addrconf_notify+0x794/0x1010
 notifier_call_chain+0x1b6/0x3e0
 register_netdevice+0x1608/0x1ae0
 macvlan_common_newlink+0x120a/0x1980
 rtnl_newlink_create+0x310/0xb00
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88802e7a4180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802e7a4200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88802e7a4280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                          ^
 ffff88802e7a4300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802e7a4380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
