[PATCH] drm/amdkfd: potential error pointer dereference in ioctl

[Kim, Jonathan]

[AMD Official Use Only - General]

> -----Original Message-----
> From: Dan Carpenter <dan.carpenter at linaro.org>
> Sent: Tuesday, June 6, 2023 4:34 AM
> To: Kim, Jonathan <Jonathan.Kim at amd.com>
> Cc: Kuehling, Felix <Felix.Kuehling at amd.com>; Deucher, Alexander
> <Alexander.Deucher at amd.com>; Koenig, Christian
> <Christian.Koenig at amd.com>; Pan, Xinhui <Xinhui.Pan at amd.com>; David
> Airlie <airlied at gmail.com>; Daniel Vetter <daniel at ffwll.ch>; amd-
> gfx at lists.freedesktop.org; kernel-janitors at vger.kernel.org
> Subject: [PATCH] drm/amdkfd: potential error pointer dereference in ioctl
>
> Caution: This message originated from an External Source. Use proper
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>
>
> The "target" either comes from kfd_create_process() which returns error
> pointers on error or kfd_lookup_process_by_pid() which returns NULL on
> error.  So we need to check for both types of errors.
>
> Fixes: a42e42c4e3b1 ("drm/amdkfd: prepare per-process debug enable and
> disable")
> Signed-off-by: Dan Carpenter <dan.carpenter at linaro.org>

Thank you for catching this.
This looks good to me.

Reviewed-by: Jonathan Kim <jonathan.kim at amd.com>

> ---
> I'm not sure how to compile this code or why I'm seeing this warning
> again after two years...  Very strange.
>
>  drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> index fc385000c007..6a27b000a246 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> @@ -2920,9 +2920,9 @@ static int kfd_ioctl_set_debug_trap(struct file
> *filep, struct kfd_process *p, v
>                 target = kfd_lookup_process_by_pid(pid);
>         }
>
> -       if (!target) {
> +       if (IS_ERR_OR_NULL(target)) {
>                 pr_debug("Cannot find process PID %i to debug\n", args->pid);
> -               r = -ESRCH;
> +               r = target ? PTR_ERR(target) : -ESRCH;
>                 goto out;
>         }
>
> --
> 2.39.2