ptr_ring: try vmalloc() when kmalloc() fails

commit 0bf7800f1799b5b1fd7d4f024e9ece53ac489011 upstream.

This patch switch to use kvmalloc_array() for using a vmalloc()
fallback to help in case kmalloc() fails.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
index bb515163bac3f2c492bb67d5c61bd1771257726e..35d125569e6848e03992b5a5ca9d1413bbb185fa 100644 (file)
--- a/include/linux/ptr_ring.h
+++ b/include/linux/ptr_ring.h
@@ -445,11 +445,14 @@ static inline int ptr_ring_consume_batched_bh(struct ptr_ring *r,
        __PTR_RING_PEEK_CALL_v; \
 })
 
+/* Not all gfp_t flags (besides GFP_KERNEL) are allowed. See
+ * documentation for vmalloc for which of them are legal.
+ */
 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);
+       return kvmalloc_array(size, sizeof(void *), gfp | __GFP_ZERO);
 }
 
 static inline void __ptr_ring_set_size(struct ptr_ring *r, int size)
@@ -582,7 +585,7 @@ static inline int ptr_ring_resize(struct ptr_ring *r, int size, gfp_t gfp,
        spin_unlock(&(r)->producer_lock);
        spin_unlock_irqrestore(&(r)->consumer_lock, flags);
 
-       kfree(old);
+       kvfree(old);
 
        return 0;
 }
@@ -622,7 +625,7 @@ static inline int ptr_ring_resize_multiple(struct ptr_ring **rings,
        }
 
        for (i = 0; i < nrings; ++i)
-               kfree(queues[i]);
+               kvfree(queues[i]);
 
        kfree(queues);
 
@@ -630,7 +633,7 @@ static inline int ptr_ring_resize_multiple(struct ptr_ring **rings,
 
 nomem:
        while (--i >= 0)
-               kfree(queues[i]);
+               kvfree(queues[i]);
 
        kfree(queues);
 
@@ -645,7 +648,7 @@ static inline void ptr_ring_cleanup(struct ptr_ring *r, void (*destroy)(void *))
        if (destroy)
                while ((ptr = ptr_ring_consume(r)))
                        destroy(ptr);
-       kfree(r->queue);
+       kvfree(r->queue);
 }
 
 #endif /* _LINUX_PTR_RING_H  */