Re: [PATCH -next] x86/events:Use struct_size() helper in kzalloc()

[linyujun (C)]

Thank you for your suggestion. I will modify the patch according
to your suggestion and make the v2 version.

Thanks
--
LinYujun

在 2022/5/18 21:49, Gustavo A. R. Silva 写道:
> On Wed, May 18, 2022 at 09:16:26PM +0800, Lin Yujun wrote:
> > Replace sizeof() with struct_size() to avoid potential integer
> > or heap overflow.
> This is not exactly what the patch does.
>
> Your patch is replacing the open-coded calculation of the total amount
> of memory to be allocated for rapl_pmus with struct_size().
>
> > Also, address the following sparse warnings:
> > arch/x86/events/rapl.c:685:16: warning: using sizeof on a
> > flexible structure
> This does not address this warning because struct_size()
> still make use of sizeof on the struct-with-flex-array,
> internally.
>
> So, the mention to the sparse warning should be removed from
> this changelog text.
>
> > Signed-off-by: Lin Yujun <linyujun809@xxxxxxxxxx>
> > ---
> >   arch/x86/events/rapl.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/events/rapl.c b/arch/x86/events/rapl.c
> > index 77e3a47af5ad..c7e79f0ac04f 100644
> > --- a/arch/x86/events/rapl.c
> > +++ b/arch/x86/events/rapl.c
> > @@ -685,7 +685,7 @@ static int __init init_rapl_pmus(void)
> >   	int maxdie = topology_max_packages() * topology_max_die_per_package();
> >   	size_t size;
> >   
> > -	size = sizeof(*rapl_pmus) + maxdie * sizeof(struct rapl_pmu *);
> > +	size = struct_size(rapl_pmus, pmus, maxdie);
> >   	rapl_pmus = kzalloc(size, GFP_KERNEL);
> It seems that in this case, size could be entirely replaced by
> struct_size().
>
> Thanks
> --
> Gustavo
> .