| Message ID | 20220926142042.2725-1-chao@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v3] mm/slub: clean up create_unique_id() | expand |
On 9/26/22 16:20, Chao Yu wrote: > From: Chao Yu <chao.yu@oppo.com> > > As Christophe JAILLET suggested: > > In create_unique_id(), > > "looks that ID_STR_LENGTH could even be reduced to 32 or 16. > > The 2nd BUG_ON at the end of the function could certainly be just > removed as well or remplaced by a: > if (p > name + ID_STR_LENGTH - 1) { > kfree(name); > return -E<something>; > } > " > > According to above suggestion, let's do below cleanups: > 1. reduce ID_STR_LENGTH to 32, as the buffer size should be enough; > 2. use WARN_ON instead of BUG_ON() and return error if check condition > is true; > 3. use snprintf instead of sprintf to avoid overflow. > > Link: https://lore.kernel.org/linux-mm/2025305d-16db-abdf-6cd3-1fb93371c2b4@wanadoo.fr/ > Fixes: 81819f0fc828 ("SLUB core") > Suggested-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> > Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> > Signed-off-by: Chao Yu <chao.yu@oppo.com> Thanks, added to slab.git for-next. > --- > v3: > - clean up codes > - fix size parameter of snprintf() > mm/slub.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/mm/slub.c b/mm/slub.c > index 4b98dff9be8e..4d3ee0924533 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -5890,7 +5890,7 @@ static inline struct kset *cache_kset(struct kmem_cache *s) > return slab_kset; > } > > -#define ID_STR_LENGTH 64 > +#define ID_STR_LENGTH 32 > > /* Create a unique string id for a slab cache: > * > @@ -5924,9 +5924,12 @@ static char *create_unique_id(struct kmem_cache *s) > *p++ = 'A'; > if (p != name + 1) > *p++ = '-'; > - p += sprintf(p, "%07u", s->size); > + p += snprintf(p, ID_STR_LENGTH - (p - name), "%07u", s->size); > > - BUG_ON(p > name + ID_STR_LENGTH - 1); > + if (WARN_ON(p > name + ID_STR_LENGTH - 1)) { > + kfree(name); > + return ERR_PTR(-EINVAL); > + } > return name; > } >
diff --git a/mm/slub.c b/mm/slub.c index 4b98dff9be8e..4d3ee0924533 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -5890,7 +5890,7 @@ static inline struct kset *cache_kset(struct kmem_cache *s) return slab_kset; } -#define ID_STR_LENGTH 64 +#define ID_STR_LENGTH 32 /* Create a unique string id for a slab cache: * @@ -5924,9 +5924,12 @@ static char *create_unique_id(struct kmem_cache *s) *p++ = 'A'; if (p != name + 1) *p++ = '-'; - p += sprintf(p, "%07u", s->size); + p += snprintf(p, ID_STR_LENGTH - (p - name), "%07u", s->size); - BUG_ON(p > name + ID_STR_LENGTH - 1); + if (WARN_ON(p > name + ID_STR_LENGTH - 1)) { + kfree(name); + return ERR_PTR(-EINVAL); + } return name; }