On Tue, 2020-06-30 at 10:57 +0200, David Hildenbrand wrote: > On 29.06.20 21:21, Joe Perches wrote: > > On Mon, 2020-06-29 at 12:54 +0200, David Hildenbrand wrote: > > > On 28.06.20 19:37, Joe Perches wrote: > > > > On Sun, 2020-06-28 at 17:25 +0200, Bartosz Golaszewski wrote: > > > > > From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx> > > > > > > > > > > Memory allocated with kstrdup_const() must not be passed to regular > > > > > krealloc() as it is not aware of the possibility of the chunk residing > > > > > in .rodata. Since there are no potential users of krealloc_const() > > > > > at the moment, let's just update the doc to make it explicit. > > > > > > > > Another option would be to return NULL if it's > > > > used from krealloc with a pointer into rodata > > [] > > > > diff --git a/mm/slab_common.c b/mm/slab_common.c > > [] > > > > @@ -1683,6 +1683,9 @@ static __always_inline void *__do_krealloc(const void *p, size_t new_size, > > > > * @new_size: how many bytes of memory are required. > > > > * @flags: the type of memory to allocate. > > > > * > > > > + * If the object pointed to is in rodata (likely from kstrdup_const) > > > > + * %NULL is returned. > > > > + * > > [] > > > Won't we have similar issues if somebody would do a kfree() instead of a > > > kfree_const()? So I think the original patch makes sense. > > > > Which is why I also suggested making kfree work for > > more types of memory freeing earlier this month. > > > > https://lore.kernel.org/lkml/573b3fbd5927c643920e1364230c296b23e7584d.camel@xxxxxxxxxxx/ [] > what's the real benefit that is worth spending extra runtime cycles? I very much doubt there is an actual instance where the runtime cycles matter. Where could there be a fast-path instance of free? ANd kvfree consolidation and coding simplicity make it somewhat useful.
