blktests nvme 041,042 leak memory

[Sagi Grimberg <sagi@grimberg.me>]

Just noticed that these tests generate a kmemleak complaint.

--
[ 1889.516324] kmemleak: 2 new suspected memory leaks (see 
/sys/kernel/debug/kmemleak)
[13221.498042] loop6: detected capacity change from 0 to 8
^C
root@nvme:~# cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff91488fb07200 (size 256):
   comm "nvme", pid 29344, jiffies 4295069699
   hex dump (first 32 bytes):
     00 00 00 00 00 00 00 00 08 72 b0 8f 48 91 ff ff .........r..H...
     08 72 b0 8f 48 91 ff ff 00 d6 55 a2 ff ff ff ff .r..H.....U.....
   backtrace (crc 36f6c278):
     [<ffffffffa2b8b46a>] kmemleak_alloc+0x4a/0x90
     [<ffffffffa1e57897>] kmalloc_trace+0x2f7/0x3a0
     [<ffffffffa2562fd0>] device_add+0x510/0x8c0
     [<ffffffffa1ee5b9e>] cdev_device_add+0x4e/0xc0
     [<ffffffffc133b7a0>] nvme_init_ctrl+0x360/0x460 [nvme_core]
     [<ffffffffc13b0af6>] 0xffffffffc13b0af6
     [<ffffffffc120e565>] 0xffffffffc120e565
     [<ffffffffa1edeb14>] vfs_write+0x104/0x490
     [<ffffffffa1edf263>] ksys_write+0x73/0x100
     [<ffffffffa1edf319>] __x64_sys_write+0x19/0x30
     [<ffffffffa1a0553e>] x64_sys_call+0x7e/0x25c0
     [<ffffffffa2b7be01>] do_syscall_64+0x71/0x130
     [<ffffffffa2c0012b>] entry_SYSCALL_64_after_hwframe+0x76/0x7e
unreferenced object 0xffff91488ed7ea00 (size 256):
   comm "nvme", pid 37478, jiffies 4295155857
   hex dump (first 32 bytes):
     00 00 00 00 00 00 00 00 08 ea d7 8e 48 91 ff ff ............H...
     08 ea d7 8e 48 91 ff ff 00 d6 55 a2 ff ff ff ff ....H.....U.....
   backtrace (crc fc1acf5):
     [<ffffffffa2b8b46a>] kmemleak_alloc+0x4a/0x90
     [<ffffffffa1e57897>] kmalloc_trace+0x2f7/0x3a0
     [<ffffffffa2562fd0>] device_add+0x510/0x8c0
     [<ffffffffa1ee5b9e>] cdev_device_add+0x4e/0xc0
     [<ffffffffc133b7a0>] nvme_init_ctrl+0x360/0x460 [nvme_core]
     [<ffffffffc13707b7>] 0xffffffffc13707b7
     [<ffffffffc120e565>] 0xffffffffc120e565
     [<ffffffffa1edeb14>] vfs_write+0x104/0x490
     [<ffffffffa1edf263>] ksys_write+0x73/0x100
     [<ffffffffa1edf319>] __x64_sys_write+0x19/0x30
     [<ffffffffa1a0553e>] x64_sys_call+0x7e/0x25c0
     [<ffffffffa2b7be01>] do_syscall_64+0x71/0x130
     [<ffffffffa2c0012b>] entry_SYSCALL_64_after_hwframe+0x76/0x7e
--

The culprit is when failing after device_initialize/cdev_device_add...
Thought I'd share it as I'm not going to address it today.