[PATCH v2] drm/amdgpu: Fix realloc of ptr

[Alex Deucher]

Applied.  Thanks!

Alex

On Mon, Feb 28, 2022 at 5:55 AM Christian König
<christian.koenig at amd.com> wrote:
>
> Am 27.02.22 um 16:33 schrieb trix at redhat.com:
> > From: Tom Rix <trix at redhat.com>
> >
> > Clang static analysis reports this error
> > amdgpu_debugfs.c:1690:9: warning: 1st function call
> >    argument is an uninitialized value
> >    tmp = krealloc_array(tmp, i + 1,
> >          ^~~~~~~~~~~~~~~~~~~~~~~~~~~
> >
> > realloc uses tmp, so tmp can not be garbage.
> > And the return needs to be checked.
> >
> > Fixes: 5ce5a584cb82 ("drm/amdgpu: add debugfs for reset registers list")
> > Signed-off-by: Tom Rix <trix at redhat.com>
>
> Yeah, stuff I missed because of the long review. I was already wondering
> what semantics krealloc_array is following for freeing up the pointer on
> error.
>
> Reviewed-by: Christian König <christian.koenig at amd.com>
>
> Thanks,
> Christian.
>
> > ---
> > v2:
> >    use 'new' to hold/check the ralloc return
> >    fix commit log mistake on ralloc freeing to using input ptr
> >
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 9 +++++++--
> >   1 file changed, 7 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> > index 9eb9b440bd438..2f4f8c5618d81 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> > @@ -1676,7 +1676,7 @@ static ssize_t amdgpu_reset_dump_register_list_write(struct file *f,
> >   {
> >       struct amdgpu_device *adev = (struct amdgpu_device *)file_inode(f)->i_private;
> >       char reg_offset[11];
> > -     uint32_t *tmp;
> > +     uint32_t *new, *tmp = NULL;
> >       int ret, i = 0, len = 0;
> >
> >       do {
> > @@ -1687,7 +1687,12 @@ static ssize_t amdgpu_reset_dump_register_list_write(struct file *f,
> >                       goto error_free;
> >               }
> >
> > -             tmp = krealloc_array(tmp, i + 1, sizeof(uint32_t), GFP_KERNEL);
> > +             new = krealloc_array(tmp, i + 1, sizeof(uint32_t), GFP_KERNEL);
> > +             if (!new) {
> > +                     ret = -ENOMEM;
> > +                     goto error_free;
> > +             }
> > +             tmp = new;
> >               if (sscanf(reg_offset, "%X %n", &tmp[i], &ret) != 1) {
> >                       ret = -EINVAL;
> >                       goto error_free;
>