On 11/01, Yuan Can wrote:
> A memory leak was reported after the vkms module install failed.
>
> unreferenced object 0xffff88810bc28520 (size 16):
> comm "modprobe", pid 9662, jiffies 4298009455 (age 42.590s)
> hex dump (first 16 bytes):
> 01 01 00 64 81 88 ff ff 00 00 dc 0a 81 88 ff ff ...d............
> backtrace:
> [<00000000e7561ff8>] kmalloc_trace+0x27/0x60
> [<000000000b1954a0>] 0xffffffffc45200a9
> [<00000000abbf1da0>] do_one_initcall+0xd0/0x4f0
> [<000000001505ee87>] do_init_module+0x1a4/0x680
> [<00000000958079ad>] load_module+0x6249/0x7110
> [<00000000117e4696>] __do_sys_finit_module+0x140/0x200
> [<00000000f74b12d2>] do_syscall_64+0x35/0x80
> [<000000008fc6fcde>] entry_SYSCALL_64_after_hwframe+0x46/0xb0
>
> The reason is that the vkms_init() returns without checking the return
> value of vkms_create(), and if the vkms_create() failed, the config
> allocated at the beginning of vkms_init() is leaked.
>
> vkms_init()
> config = kmalloc(...) # config allocated
> ...
> return vkms_create() # vkms_create failed and config is leaked
>
> Fix this problem by checking return value of vkms_create() and free the
> config if error happened.
>
> Fixes: 2df7af93fdad ("drm/vkms: Add vkms_config type")
> Signed-off-by: Yuan Can <yuancan@xxxxxxxxxx>
> ---
> drivers/gpu/drm/vkms/vkms_drv.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
> index 0ffe5f0e33f7..dfe983eaa07f 100644
> --- a/drivers/gpu/drm/vkms/vkms_drv.c
> +++ b/drivers/gpu/drm/vkms/vkms_drv.c
> @@ -218,6 +218,7 @@ static int vkms_create(struct vkms_config *config)
>
> static int __init vkms_init(void)
> {
> + int ret;
> struct vkms_config *config;
>
> config = kmalloc(sizeof(*config), GFP_KERNEL);
> @@ -230,7 +231,11 @@ static int __init vkms_init(void)
> config->writeback = enable_writeback;
> config->overlay = enable_overlay;
>
> - return vkms_create(config);
> + ret = vkms_create(config);
> + if (ret)
> + kfree(config);
> +
> + return ret;
Good catch. Thanks,
Reviewed-by: Melissa Wen <mwen@xxxxxxxxxx>
> }
>
> static void vkms_destroy(struct vkms_config *config)
> --
> 2.17.1
>
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