lkml.org 
[lkml]   [2022]   [Dec]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    SubjectRe: [PATCH] mm, slub: fix uninitialized variable in __slab_free
    On Fri, Dec 16, 2022 at 03:31:19AM +0000, Chen Jun wrote:
    > new.frozen is not initialized before it is used.
    >
    > Fixes: 2cfb7455d223 ("slub: Rework allocator fastpaths")
    > Signed-off-by: Chen Jun <chenjun102@huawei.com>
    > ---
    > mm/slub.c | 1 +
    > 1 file changed, 1 insertion(+)
    >
    > diff --git a/mm/slub.c b/mm/slub.c
    > index 13459c69095a..8628c88875b6 100644
    > --- a/mm/slub.c
    > +++ b/mm/slub.c
    > @@ -3593,6 +3593,7 @@ static void __slab_free(struct kmem_cache *s, struct slab *slab,
    > return;
    > }
    >
    > + new.frozen = 0;
    > do {
    > if (unlikely(n)) {
    > spin_unlock_irqrestore(&n->list_lock, flags);
    > --
    > 2.17.1

    This is incorrect because new.frozen is initialized when new.counters is
    initialized.

    See definition of struct slab in mm/slab.h:

    struct slab {

    [...]
    union {
    unsigned long counters;
    struct {
    unsigned inuse:16;
    unsigned objects:15;
    unsigned frozen:1;
    };
    };
    }

    --
    Thanks,
    Hyeonggon
    \
     
     \ /
      Last update: 2022-12-16 08:43    [W:2.312 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site