__dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x138/0x197 lib/dump_stack.c:53
 fail_dump lib/fault-inject.c:51 [inline]
 should_fail.cold+0x10f/0x159 lib/fault-inject.c:149
 should_failslab+0xdb/0x130 mm/failslab.c:32
 slab_pre_alloc_hook mm/slab.h:421 [inline]
 slab_alloc mm/slab.c:3376 [inline]
 __do_kmalloc mm/slab.c:3718 [inline]
 __kmalloc+0x2f0/0x7a0 mm/slab.c:3729
==================================================================
BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:347 [inline]
BUG: KASAN: slab-out-of-bounds in pdu_read+0x90/0xd0 net/9p/protocol.c:64
Read of size 13312 at addr ffff8880546d0eed by task syz-executor.4/7556
 kmalloc_array include/linux/slab.h:607 [inline]
 kcalloc include/linux/slab.h:618 [inline]
 old_dev_ioctl.isra.0+0x61b/0x1460 net/bridge/br_ioctl.c:173

 br_dev_ioctl+0x62/0xe7 net/bridge/br_ioctl.c:392
 dev_ifsioc+0x5fc/0x7f0 net/core/dev_ioctl.c:354
 dev_ioctl+0x4b7/0xcb0 net/core/dev_ioctl.c:589
 sock_ioctl+0x170/0x470 net/socket.c:1012
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459a29
RSP: 002b:00007f408da49c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f408da49c90 RCX: 0000000000459a29
RDX: 0000000020000080 RSI: 00000000000089f0 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f408da4a6d4
R13: 00000000004c54fa R14: 00000000004d9bb0 R15: 0000000000000004
CPU: 0 PID: 7556 Comm: syz-executor.4 Not tainted 4.14.146 #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+0x138/0x197 lib/dump_stack.c:53
 print_address_description.cold+0x7c/0x1dc 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+0xa9/0x2af mm/kasan/report.c:393
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x123/0x190 mm/kasan/kasan.c:267
 memcpy+0x24/0x50 mm/kasan/kasan.c:302
 memcpy include/linux/string.h:347 [inline]
 pdu_read+0x90/0xd0 net/9p/protocol.c:64
 p9pdu_vreadf net/9p/protocol.c:167 [inline]
 p9pdu_readf+0x379/0x1780 net/9p/protocol.c:540
 p9_client_version net/9p/client.c:990 [inline]
 p9_client_create+0xa1f/0x1120 net/9p/client.c:1088
 v9fs_session_init+0x1dc/0x1620 fs/9p/v9fs.c:422
 v9fs_mount+0x7d/0x870 fs/9p/vfs_super.c:135
 mount_fs+0x97/0x2a1 fs/super.c:1237
 vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x417/0x27d0 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xab/0x120 fs/namespace.c:3072
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459a29
RSP: 002b:00007f69c593ac78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000459a29
RDX: 0000000020000140 RSI: 0000000020000100 RDI: 0000000000000000
RBP: 000000000075bf20 R08: 0000000020000400 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f69c593b6d4
R13: 00000000004c5fd4 R14: 00000000004dac60 R15: 00000000ffffffff

Allocated by task 7556:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x45/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc mm/kasan/kasan.c:551 [inline]
 kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:529
 __do_kmalloc mm/slab.c:3720 [inline]
 __kmalloc+0x15d/0x7a0 mm/slab.c:3729
 kmalloc include/linux/slab.h:493 [inline]
 p9_fcall_alloc+0x1d/0x90 net/9p/client.c:242
 p9_tag_alloc net/9p/client.c:312 [inline]
 p9_client_prepare_req.part.0+0x73a/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+0x997/0x1120 net/9p/client.c:1088
 v9fs_session_init+0x1dc/0x1620 fs/9p/v9fs.c:422
 v9fs_mount+0x7d/0x870 fs/9p/vfs_super.c:135
 mount_fs+0x97/0x2a1 fs/super.c:1237
 vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x417/0x27d0 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xab/0x120 fs/namespace.c:3072
 do_syscall_64+0x1e8/0x640 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 ffff8880546d0ec0
 which belongs to the cache kmalloc-16384 of size 16384
The buggy address is located 45 bytes inside of
 16384-byte region [ffff8880546d0ec0, ffff8880546d4ec0)
The buggy address belongs to the page:
page:ffffea000151b400 count:1 mapcount:0 mapping:ffff8880546d0ec0 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000008100(slab|head)
raw: 01fffc0000008100 ffff8880546d0ec0 0000000000000000 0000000100000001
raw: ffffea0001532820 ffffea00014c9220 ffff8880aa802200 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880546d2d80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880546d2e00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880546d2e80: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
                                                       ^
 ffff8880546d2f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880546d2f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================