ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE

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
Fixes: 2e0ab8ca83c12 ("ptr_ring: array based FIFO for pointers")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
index 1883d6137e9b70915c50ad7c1eb36839c80dd555..6051a5fe69131d880fd0a0e1cb379e4b2208a4cd 100644 (file)
--- 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 * sizeof(void *) > KMALLOC_MAX_SIZE)
+               return NULL;
        return kcalloc(size, sizeof(void *), gfp);
 }