device lo entered promiscuous mode
qtaguid: iface_stat: iface_check_stats_reset_and_adjust(lo): iface reset its stats unexpectedly
device lo entered promiscuous mode
==================================================================
BUG: KASAN: slab-out-of-bounds in pdu_read net/9p/protocol.c:59 [inline]
BUG: KASAN: slab-out-of-bounds in p9pdu_vreadf net/9p/protocol.c:162 [inline]
BUG: KASAN: slab-out-of-bounds in p9pdu_readf+0x535/0x1d50 net/9p/protocol.c:535
Read of size 31189 at addr ffff8801b827802d by task syz-executor4/7122

CPU: 1 PID: 7122 Comm: syz-executor4 Not tainted 4.9.112-g9e79039 #59
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d31875a0 ffffffff81eb3249 ffffea0006e09e00 ffff8801b827802d
 0000000000000000 ffff8801b827a025 00000000cd35bff3 ffff8801d31875d8
 ffffffff81567bd9 ffff8801b827802d 00000000000079d5 0000000000000000
Call Trace:
 [<ffffffff81eb3249>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb3249>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81567bd9>] print_address_description+0x6c/0x234 mm/kasan/report.c:256
 [<ffffffff81567fe3>] kasan_report_error mm/kasan/report.c:355 [inline]
 [<ffffffff81567fe3>] kasan_report.cold.6+0x242/0x2fe mm/kasan/report.c:412
 [<ffffffff8153aa9f>] check_memory_region_inline mm/kasan/kasan.c:318 [inline]
 [<ffffffff8153aa9f>] check_memory_region+0x14f/0x1b0 mm/kasan/kasan.c:325
 [<ffffffff8153b0e3>] memcpy+0x23/0x50 mm/kasan/kasan.c:360
 [<ffffffff839bff15>] pdu_read net/9p/protocol.c:59 [inline]
 [<ffffffff839bff15>] p9pdu_vreadf net/9p/protocol.c:162 [inline]
 [<ffffffff839bff15>] p9pdu_readf+0x535/0x1d50 net/9p/protocol.c:535
 [<ffffffff839b485f>] p9_client_version net/9p/client.c:960 [inline]
 [<ffffffff839b485f>] p9_client_create+0xa3f/0x10a0 net/9p/client.c:1043
 [<ffffffff8195b503>] v9fs_session_init+0x333/0x13a0 fs/9p/v9fs.c:343
 [<ffffffff8194cdfd>] v9fs_mount+0x7d/0x810 fs/9p/vfs_super.c:130
 [<ffffffff8157e2ac>] mount_fs+0x28c/0x370 fs/super.c:1206
 [<ffffffff815dda71>] vfs_kern_mount.part.29+0xd1/0x3d0 fs/namespace.c:991
 [<ffffffff815e5399>] vfs_kern_mount fs/namespace.c:973 [inline]
 [<ffffffff815e5399>] do_new_mount fs/namespace.c:2513 [inline]
 [<ffffffff815e5399>] do_mount+0x3c9/0x2740 fs/namespace.c:2835
 [<ffffffff815e80ee>] SYSC_mount fs/namespace.c:3051 [inline]
 [<ffffffff815e80ee>] SyS_mount+0xfe/0x110 fs/namespace.c:3028
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f9f53>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

The buggy address belongs to the page:
page:ffffea0006e09e00 count:1 mapcount:0 mapping:          (null) index:0x0 compound_mapcount: 0
flags: 0x8000000000004000(head)
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801b8279f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801b8279f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801b827a000: 00 00 00 00 fe fe fe fe fe fe fe fe fe fe fe fe
                               ^
 ffff8801b827a080: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
 ffff8801b827a100: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
==================================================================