Messages in this thread | | | Date | Thu, 8 Feb 2018 17:44:48 +0200 | From | "Michael S. Tsirkin" <> | Subject | Re: [PATCH net] ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE |
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On Wed, Feb 07, 2018 at 04:08:25PM +0800, Jason Wang wrote: > To avoid slab to warn about exceeded size, fail early if queue > occupies more than KMALLOC_MAX_SIZE. > > Reported-by: syzbot+e4d4f9ddd4295539735d@syzkaller.appspotmail.com > Signed-off-by: Jason Wang <jasowang@redhat.com> > --- > include/linux/ptr_ring.h | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h > index 1883d61..4b862da 100644 > --- a/include/linux/ptr_ring.h > +++ b/include/linux/ptr_ring.h > @@ -466,6 +466,8 @@ static inline int ptr_ring_consume_batched_bh(struct ptr_ring *r, > > static inline void **__ptr_ring_init_queue_alloc(unsigned int size, gfp_t gfp) > { > + if (size > KMALLOC_MAX_SIZE) > + return NULL; > return kcalloc(size, sizeof(void *), gfp); > }
I guess this approach does begin to make more sense at least as a temporary stop-gap.
But does this actually prevent the crash in all cases?
size is in void* entry units, KMALLOC_MAX_SIZE is in bytes.
> > -- > 2.7.4
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