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BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:347 [inline]
BUG: KASAN: slab-out-of-bounds in pdu_read+0x8a/0xc0 net/9p/protocol.c:64
Read of size 50432 at addr ffff88805d5cb7ad by task syz-executor.1/418

CPU: 0 PID: 418 Comm: syz-executor.1 Not tainted 4.14.175-syzkaller #0
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+0x13e/0x194 lib/dump_stack.c:58
 print_address_description.cold+0x7c/0x1e2 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0xa9/0x2ae mm/kasan/report.c:393
 memcpy+0x20/0x50 mm/kasan/kasan.c:302
 memcpy include/linux/string.h:347 [inline]
 pdu_read+0x8a/0xc0 net/9p/protocol.c:64
 p9pdu_vreadf net/9p/protocol.c:167 [inline]
 p9pdu_readf+0x379/0x1790 net/9p/protocol.c:540
 p9_client_version net/9p/client.c:990 [inline]
 p9_client_create+0xa1f/0x10f0 net/9p/client.c:1088
 v9fs_session_init+0x1dc/0x1620 fs/9p/v9fs.c:422
 v9fs_mount+0x79/0x850 fs/9p/vfs_super.c:135
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x3c0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x3c9/0x24f0 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xa8/0x120 fs/namespace.c:3072
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c889
RSP: 002b:00007f5b681cbc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f5b681cc6d4 RCX: 000000000045c889
RDX: 0000000020000180 RSI: 0000000020000500 RDI: 0000000000000000
RBP: 000000000076bf00 R08: 0000000020000700 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000074a R14: 00000000004ca0c5 R15: 000000000076bf0c

Allocated by task 418:
 save_stack+0x32/0xa0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc mm/kasan/kasan.c:551 [inline]
 kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:529
 __do_kmalloc mm/slab.c:3720 [inline]
 __kmalloc+0x15b/0x7c0 mm/slab.c:3729
 kmalloc include/linux/slab.h:493 [inline]
 p9_fcall_alloc+0x19/0x90 net/9p/client.c:242
 p9_tag_alloc net/9p/client.c:312 [inline]
 p9_client_prepare_req.part.0+0x72f/0xa90 net/9p/client.c:728
 p9_client_prepare_req net/9p/client.c:718 [inline]
 p9_client_rpc+0x170/0x1180 net/9p/client.c:763
 p9_client_version net/9p/client.c:980 [inline]
 p9_client_create+0x997/0x10f0 net/9p/client.c:1088
 v9fs_session_init+0x1dc/0x1620 fs/9p/v9fs.c:422
 v9fs_mount+0x79/0x850 fs/9p/vfs_super.c:135
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x3c0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x3c9/0x24f0 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xa8/0x120 fs/namespace.c:3072
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff88805d5cb780
 which belongs to the cache kmalloc-16384 of size 16384
The buggy address is located 45 bytes inside of
 16384-byte region [ffff88805d5cb780, ffff88805d5cf780)
The buggy address belongs to the page:
page:ffffea0001757200 count:1 mapcount:0 mapping:ffff88805d5cb780 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffff88805d5cb780 0000000000000000 0000000100000001
raw: ffffea0001757020 ffffea000044a220 ffff88812fe55200 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88805d5cd680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
netlink: 14 bytes leftover after parsing attributes in process `syz-executor.0'.
 ffff88805d5cd700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88805d5cd780: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc
                               ^
 ffff88805d5cd800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88805d5cd880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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