Messages in this thread | | | Subject | Re: [PATCH] mm: check the function kmalloc_slab return value | From | tury <> | Date | Tue, 14 Jun 2022 17:26:40 +0800 |
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在 2022年06月14日 16:48, Vlastimil Babka 写道: > On 6/14/22 10:39, Ren Yu wrote: >> As the possible failure of the kmalloc_slab, >> it should be better to check it. > AFAIK failure is not possible, kmalloc_slab() is not an allocation function, > it just returns a member of kmalloc_caches array, which is initialized > elsewhere and shouldn't contain NULLs. So the patch seems unnecessary to me. > >> Signed-off-by: Ren Yu <renyu@nfschina.com> >> Reported-by: kernel test robot <lkp@intel.com> >> --- >> v2: >> - fix build waring integer from pointer without a cast >> --- >> --- >> mm/slab.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/mm/slab.c b/mm/slab.c >> index f8cd00f4ba13..72135e555827 100644 >> --- a/mm/slab.c >> +++ b/mm/slab.c >> @@ -2064,6 +2064,8 @@ int __kmem_cache_create(struct kmem_cache *cachep, slab_flags_t flags) >> if (OFF_SLAB(cachep)) { >> cachep->freelist_cache = >> kmalloc_slab(cachep->freelist_size, 0u); >> + if (unlikely(ZERO_OR_NULL_PTR(cachep->freelist_cache))) > The usual way is "if (!cachep->freelist_cache)". Not sure why check for ZERO. > >> + return cachep->freelist_cache; > So in case of NULL this would return NULL, thus 0, but __kmem_cache_create() > return 0 on success, so it's wrong. You would have to return e.g. -ENOMEM. Thanks for the advice ,I'll be re-patching > >> } >> >> err = setup_cpu_cache(cachep, gfp); >
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