| From | Dmitry Vyukov <> | Date | Tue, 15 Jul 2014 10:08:35 +0400 | Subject | Re: [RFC/PATCH RESEND -next 20/21] fs: dcache: manually unpoison dname after allocation to shut up kasan's reports |
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On Tue, Jul 15, 2014 at 10:12 AM, Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote: > On Wed, Jul 09, 2014 at 03:30:14PM +0400, Andrey Ryabinin wrote: >> We need to manually unpoison rounded up allocation size for dname >> to avoid kasan's reports in __d_lookup_rcu. >> __d_lookup_rcu may validly read a little beyound allocated size. > > If it read a little beyond allocated size, IMHO, it is better to > allocate correct size. > > kmalloc(name->len + 1, GFP_KERNEL); --> > kmalloc(roundup(name->len + 1, sizeof(unsigned long ), GFP_KERNEL); > > Isn't it?
I absolutely agree!
> Thanks. > >> >> Reported-by: Dmitry Vyukov <dvyukov@google.com> >> Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> >> --- >> fs/dcache.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/fs/dcache.c b/fs/dcache.c >> index b7e8b20..dff64f2 100644 >> --- a/fs/dcache.c >> +++ b/fs/dcache.c >> @@ -38,6 +38,7 @@ >> #include <linux/prefetch.h> >> #include <linux/ratelimit.h> >> #include <linux/list_lru.h> >> +#include <linux/kasan.h> >> #include "internal.h" >> #include "mount.h" >> >> @@ -1412,6 +1413,8 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name) >> kmem_cache_free(dentry_cache, dentry); >> return NULL; >> } >> + unpoison_shadow(dname, >> + roundup(name->len + 1, sizeof(unsigned long))); >> } else { >> dname = dentry->d_iname; >> } >> -- >> 1.8.5.5 >> >> -- >> To unsubscribe, send a message with 'unsubscribe linux-mm' in >> the body to majordomo@kvack.org. For more info on Linux MM, >> see: http://www.linux-mm.org/ . >> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
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