Linux Virtualization - Mar 2023 - [PATCH 1/1] vhost_task: Fix vhost_task_create return value

vhost_task_create is supposed to return the vhost_task or NULL on
failure. This fixes it to return the correct value when the allocation
of the struct fails.

Fixes: 77feab3c4156 ("vhost_task: Allow vhost layer to use
copy_process") # mainline only
Reported-by: syzbot+6b27b2d2aba1c80cc13b at syzkaller.appspotmail.com
Signed-off-by: Mike Christie <michael.christie at oracle.com>
---
 kernel/vhost_task.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/vhost_task.c b/kernel/vhost_task.c
index 4b8aff160640..b7cbd66f889e 100644
--- a/kernel/vhost_task.c
+++ b/kernel/vhost_task.c
@@ -88,7 +88,7 @@ struct vhost_task *vhost_task_create(int (*fn)(void *), void
*arg,
 
 	vtsk = kzalloc(sizeof(*vtsk), GFP_KERNEL);
 	if (!vtsk)
-		return ERR_PTR(-ENOMEM);
+		return NULL;
 	init_completion(&vtsk->exited);
 	vtsk->data = arg;
 	vtsk->fn = fn;
-- 
2.25.1

On Wed, Mar 22, 2023 at 01:56:05PM -0500, Mike Christie
wrote:
> vhost_task_create is supposed to return the vhost_task or NULL on
> failure. This fixes it to return the correct value when the allocation
> of the struct fails.
> 
> Fixes: 77feab3c4156 ("vhost_task: Allow vhost layer to use
copy_process") # mainline only
> Reported-by: syzbot+6b27b2d2aba1c80cc13b at syzkaller.appspotmail.com
> Signed-off-by: Mike Christie <michael.christie at oracle.com>
Acked-by: Michael S. Tsirkin <mst at redhat.com>

The affected patch is not upstream yet, right?
I don't know if the tree in question allows rebases - linux-next
does. So ideally it would be squashed to avoid issues during bisect.
Still it's error path so I guess not a tragedy even without squashing.
> ---
>  kernel/vhost_task.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/vhost_task.c b/kernel/vhost_task.c
> index 4b8aff160640..b7cbd66f889e 100644
> --- a/kernel/vhost_task.c
> +++ b/kernel/vhost_task.c
> @@ -88,7 +88,7 @@ struct vhost_task *vhost_task_create(int (*fn)(void *),
void *arg,
>  
>  	vtsk = kzalloc(sizeof(*vtsk), GFP_KERNEL);
>  	if (!vtsk)
> -		return ERR_PTR(-ENOMEM);
> +		return NULL;
>  	init_completion(&vtsk->exited);
>  	vtsk->data = arg;
>  	vtsk->fn = fn;
> -- 
> 2.25.1

On Wed, Mar 22, 2023 at 01:56:05PM -0500, Mike Christie
wrote:
>vhost_task_create is supposed to return the vhost_task or NULL on
>failure. This fixes it to return the correct value when the allocation
>of the struct fails.
>
>Fixes: 77feab3c4156 ("vhost_task: Allow vhost layer to use
copy_process") # mainline only
>Reported-by: syzbot+6b27b2d2aba1c80cc13b at syzkaller.appspotmail.com
>Signed-off-by: Mike Christie <michael.christie at oracle.com>
>---
> kernel/vhost_task.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Reviewed-by: Stefano Garzarella <sgarzare at redhat.com>
>
>diff --git a/kernel/vhost_task.c b/kernel/vhost_task.c
>index 4b8aff160640..b7cbd66f889e 100644
>--- a/kernel/vhost_task.c
>+++ b/kernel/vhost_task.c
>@@ -88,7 +88,7 @@ struct vhost_task *vhost_task_create(int (*fn)(void *),
void *arg,
>
> 	vtsk = kzalloc(sizeof(*vtsk), GFP_KERNEL);
> 	if (!vtsk)
>-		return ERR_PTR(-ENOMEM);
>+		return NULL;
> 	init_completion(&vtsk->exited);
> 	vtsk->data = arg;
> 	vtsk->fn = fn;
>-- 
>2.25.1
>