netlink: 4 bytes leftover after parsing attributes in process `syz-executor2'.
==================================================================
BUG: KASAN: slab-out-of-bounds in fscache_set_key fs/fscache/cookie.c:120 [inline]
BUG: KASAN: slab-out-of-bounds in fscache_alloc_cookie+0x7ad/0x880 fs/fscache/cookie.c:171
Read of size 4 at addr ffff8801ce9af8d4 by task syz-executor5/20690

CPU: 1 PID: 20690 Comm: syz-executor5 Not tainted 4.19.0-rc8+ #189
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+0x1c4/0x2b4 lib/dump_stack.c:113
 print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432
 fscache_set_key fs/fscache/cookie.c:120 [inline]
 fscache_alloc_cookie+0x7ad/0x880 fs/fscache/cookie.c:171
 __fscache_acquire_cookie+0x230/0xb60 fs/fscache/cookie.c:303
 fscache_acquire_cookie include/linux/fscache.h:338 [inline]
 nfs_fscache_get_client_cookie+0x463/0x600 fs/nfs/fscache.c:85
 nfs_alloc_client+0x563/0x760 fs/nfs/client.c:188
 nfs_get_client+0x8e8/0x14d0 fs/nfs/client.c:430
 nfs_init_server+0x357/0x1010 fs/nfs/client.c:670
 nfs_create_server+0x86/0x5f0 fs/nfs/client.c:954
 nfs_try_mount+0x180/0xa80 fs/nfs/super.c:1884
 nfs_fs_mount+0x17f8/0x2f1c fs/nfs/super.c:2695
 mount_fs+0xae/0x31d fs/super.c:1261
 vfs_kern_mount.part.35+0xdc/0x4f0 fs/namespace.c:961
 vfs_kern_mount fs/namespace.c:951 [inline]
 do_new_mount fs/namespace.c:2457 [inline]
 do_mount+0x581/0x31f0 fs/namespace.c:2787
 __do_compat_sys_mount fs/compat.c:125 [inline]
 __se_compat_sys_mount fs/compat.c:92 [inline]
 __ia32_compat_sys_mount+0x5d5/0x860 fs/compat.c:92
 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
 do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7fb6ca9
Code: 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 0c 24 c3 8b 1c 24 c3 90 90 90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000f5fb20cc EFLAGS: 00000296 ORIG_RAX: 0000000000000015
RAX: ffffffffffffffda RBX: 0000000020000480 RCX: 0000000020343ff8
RDX: 000000002015bffc RSI: 0000000000000000 RDI: 000000002000a000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 20690:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
 __do_kmalloc mm/slab.c:3718 [inline]
 __kmalloc+0x14e/0x760 mm/slab.c:3727
 kmalloc include/linux/slab.h:518 [inline]
 kzalloc include/linux/slab.h:707 [inline]
 fscache_set_key fs/fscache/cookie.c:101 [inline]
 fscache_alloc_cookie+0x6f7/0x880 fs/fscache/cookie.c:171
 __fscache_acquire_cookie+0x230/0xb60 fs/fscache/cookie.c:303
 fscache_acquire_cookie include/linux/fscache.h:338 [inline]
 nfs_fscache_get_client_cookie+0x463/0x600 fs/nfs/fscache.c:85
 nfs_alloc_client+0x563/0x760 fs/nfs/client.c:188
 nfs_get_client+0x8e8/0x14d0 fs/nfs/client.c:430
 nfs_init_server+0x357/0x1010 fs/nfs/client.c:670
 nfs_create_server+0x86/0x5f0 fs/nfs/client.c:954
 nfs_try_mount+0x180/0xa80 fs/nfs/super.c:1884
 nfs_fs_mount+0x17f8/0x2f1c fs/nfs/super.c:2695
 mount_fs+0xae/0x31d fs/super.c:1261
 vfs_kern_mount.part.35+0xdc/0x4f0 fs/namespace.c:961
 vfs_kern_mount fs/namespace.c:951 [inline]
 do_new_mount fs/namespace.c:2457 [inline]
 do_mount+0x581/0x31f0 fs/namespace.c:2787
 __do_compat_sys_mount fs/compat.c:125 [inline]
 __se_compat_sys_mount fs/compat.c:92 [inline]
 __ia32_compat_sys_mount+0x5d5/0x860 fs/compat.c:92
 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
 do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

Freed by task 13893:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kfree+0xcf/0x230 mm/slab.c:3813
 kvfree+0x61/0x70 mm/util.c:452
 __vunmap+0x328/0x460 mm/vmalloc.c:1529
 vfree+0x68/0x100 mm/vmalloc.c:1593
 xt_compat_flush_offsets+0x153/0x280 net/netfilter/x_tables.c:674
 compat_get_entries net/ipv4/netfilter/ip_tables.c:1631 [inline]
 compat_do_ipt_get_ctl+0x4a8/0xc80 net/ipv4/netfilter/ip_tables.c:1656
 compat_nf_sockopt net/netfilter/nf_sockopt.c:139 [inline]
 compat_nf_getsockopt+0x9e/0x140 net/netfilter/nf_sockopt.c:163
 compat_ip_getsockopt+0x1ce/0x2a0 net/ipv4/ip_sockglue.c:1613
 inet_csk_compat_getsockopt+0x97/0x120 net/ipv4/inet_connection_sock.c:1035
 compat_tcp_getsockopt+0x49/0x80 net/ipv4/tcp.c:3594
 compat_sock_common_getsockopt+0xb4/0x150 net/core/sock.c:3008
 __compat_sys_getsockopt+0x1b6/0x8a0 net/compat.c:530
 __do_compat_sys_socketcall net/compat.c:914 [inline]
 __se_compat_sys_socketcall net/compat.c:842 [inline]
 __ia32_compat_sys_socketcall+0xb35/0x1090 net/compat.c:842
 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
 do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

The buggy address belongs to the object at ffff8801ce9af8c0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 20 bytes inside of
 32-byte region [ffff8801ce9af8c0, ffff8801ce9af8e0)
The buggy address belongs to the page:
page:ffffea00073a6bc0 count:1 mapcount:0 mapping:ffff8801da8001c0 index:0xffff8801ce9affc1
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffffea000739b4c8 ffffea00074ffec8 ffff8801da8001c0
raw: ffff8801ce9affc1 ffff8801ce9af000 000000010000003f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801ce9af780: fb fb fb fb fc fc fc fc 00 02 fc fc fc fc fc fc
 ffff8801ce9af800: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8801ce9af880: 05 fc fc fc fc fc fc fc 00 00 06 fc fc fc fc fc
                                                 ^
 ffff8801ce9af900: 00 00 00 fc fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801ce9af980: 00 01 fc fc fc fc fc fc fb fb fb fb fc fc fc fc
==================================================================