syzbot

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BUG: KASAN: use-after-free in vhost_work_queue+0xc3/0xe0 drivers/vhost/vhost.c:258
Read of size 8 at addr ffff8801b07a5228 by task syz-executor0/16635

CPU: 1 PID: 16635 Comm: syz-executor0 Not tainted 4.19.0-rc7+ #282
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_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 vhost_work_queue+0xc3/0xe0 drivers/vhost/vhost.c:258
 vhost_transport_send_pkt+0x28a/0x380 drivers/vhost/vsock.c:227
 virtio_transport_send_pkt_info+0x31d/0x460 net/vmw_vsock/virtio_transport_common.c:190
 virtio_transport_connect+0x17c/0x220 net/vmw_vsock/virtio_transport_common.c:588
 vsock_stream_connect+0x4ed/0xe40 net/vmw_vsock/af_vsock.c:1200
 __sys_connect+0x37d/0x4c0 net/socket.c:1664
 __do_sys_connect net/socket.c:1675 [inline]
 __se_sys_connect net/socket.c:1672 [inline]
 __x64_sys_connect+0x73/0xb0 net/socket.c:1672
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457569
Code: fd b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f1b2b17ec78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457569
RDX: 0000000000000010 RSI: 0000000020000200 RDI: 0000000000000008
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f1b2b17f6d4
R13: 00000000004bdb06 R14: 00000000004cc658 R15: 00000000ffffffff

Allocated by task 16635:
 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_node mm/slab.c:3682 [inline]
 __kmalloc_node+0x47/0x70 mm/slab.c:3689
 kmalloc_node include/linux/slab.h:555 [inline]
 kvmalloc_node+0xb9/0xf0 mm/util.c:423
 kvmalloc include/linux/mm.h:577 [inline]
 vhost_vsock_dev_open+0xa2/0x5a0 drivers/vhost/vsock.c:511
 misc_open+0x3ca/0x560 drivers/char/misc.c:141
 chrdev_open+0x25a/0x710 fs/char_dev.c:417
 do_dentry_open+0x499/0x1250 fs/open.c:771
 vfs_open+0xa0/0xd0 fs/open.c:880
 do_last fs/namei.c:3418 [inline]
 path_openat+0x12bf/0x5160 fs/namei.c:3534
 do_filp_open+0x255/0x380 fs/namei.c:3564
 do_sys_open+0x568/0x700 fs/open.c:1063
 __do_sys_openat fs/open.c:1090 [inline]
 __se_sys_openat fs/open.c:1084 [inline]
 __x64_sys_openat+0x9d/0x100 fs/open.c:1084
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 16634:
 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
 vhost_vsock_free drivers/vhost/vsock.c:499 [inline]
 vhost_vsock_dev_release+0x4f4/0x720 drivers/vhost/vsock.c:604
 __fput+0x385/0xa30 fs/file_table.c:278
 ____fput+0x15/0x20 fs/file_table.c:309
 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:193 [inline]
 exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8801b07a5180
 which belongs to the cache kmalloc-65536 of size 65536
The buggy address is located 168 bytes inside of
 65536-byte region [ffff8801b07a5180, ffff8801b07b5180)
The buggy address belongs to the page:
page:ffffea0006c1e800 count:1 mapcount:0 mapping:ffff8801da802500 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffffea0006c13808 ffffea0006c00808 ffff8801da802500
raw: 0000000000000000 ffff8801b07a5180 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801b07a5100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801b07a5180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801b07a5200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff8801b07a5280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801b07a5300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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