| Message ID | 20220429064051.61552-3-linmiaohe@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | A few fixup patches for z3fold | expand |
On Fri, Apr 29, 2022 at 8:40 AM Miaohe Lin <linmiaohe@huawei.com> wrote: > > alloc_slots could fail to allocate memory under heavy memory pressure. So > we should check zhdr->slots against NULL to avoid future null pointer > dereferencing. > > Fixes: fc5488651c7d ("z3fold: simplify freeing slots") > Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> > --- > mm/z3fold.c | 12 +++++++++++- > 1 file changed, 11 insertions(+), 1 deletion(-) > > diff --git a/mm/z3fold.c b/mm/z3fold.c > index c2260f5a5885..5d8c21f2bc59 100644 > --- a/mm/z3fold.c > +++ b/mm/z3fold.c > @@ -940,9 +940,19 @@ static inline struct z3fold_header *__z3fold_alloc(struct z3fold_pool *pool, > } > } > > - if (zhdr && !zhdr->slots) > + if (zhdr && !zhdr->slots) { > zhdr->slots = alloc_slots(pool, GFP_ATOMIC); > + if (!zhdr->slots) > + goto out_fail; > + } > return zhdr; > + > +out_fail: > + if (!kref_put(&zhdr->refcount, release_z3fold_page_locked)) { > + add_to_unbuddied(pool, zhdr); > + z3fold_page_unlock(zhdr); > + } > + return NULL; > } Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com> > /* > -- > 2.23.0 >
diff --git a/mm/z3fold.c b/mm/z3fold.c index c2260f5a5885..5d8c21f2bc59 100644 --- a/mm/z3fold.c +++ b/mm/z3fold.c @@ -940,9 +940,19 @@ static inline struct z3fold_header *__z3fold_alloc(struct z3fold_pool *pool, } } - if (zhdr && !zhdr->slots) + if (zhdr && !zhdr->slots) { zhdr->slots = alloc_slots(pool, GFP_ATOMIC); + if (!zhdr->slots) + goto out_fail; + } return zhdr; + +out_fail: + if (!kref_put(&zhdr->refcount, release_z3fold_page_locked)) { + add_to_unbuddied(pool, zhdr); + z3fold_page_unlock(zhdr); + } + return NULL; } /*
alloc_slots could fail to allocate memory under heavy memory pressure. So we should check zhdr->slots against NULL to avoid future null pointer dereferencing. Fixes: fc5488651c7d ("z3fold: simplify freeing slots") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> --- mm/z3fold.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)