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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        syzbot+e4d4f9ddd4295539735d@syzkaller.appspotmail.com,
        Jason Wang <jasowang@redhat.com>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.15 03/45] ptr_ring: try vmalloc() when kmalloc() fails
Date:   Fri, 23 Feb 2018 19:28:42 +0100
Message-Id: <20180223170715.783010673@linuxfoundation.org>
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4.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jason Wang <jasowang@redhat.com>

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>

---
 include/linux/ptr_ring.h |   13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

--- a/include/linux/ptr_ring.h
+++ b/include/linux/ptr_ring.h
@@ -451,11 +451,14 @@ static inline int ptr_ring_consume_batch
 	__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)
@@ -588,7 +591,7 @@ static inline int ptr_ring_resize(struct
 	spin_unlock(&(r)->producer_lock);
 	spin_unlock_irqrestore(&(r)->consumer_lock, flags);
 
-	kfree(old);
+	kvfree(old);
 
 	return 0;
 }
@@ -628,7 +631,7 @@ static inline int ptr_ring_resize_multip
 	}
 
 	for (i = 0; i < nrings; ++i)
-		kfree(queues[i]);
+		kvfree(queues[i]);
 
 	kfree(queues);
 
@@ -636,7 +639,7 @@ static inline int ptr_ring_resize_multip
 
 nomem:
 	while (--i >= 0)
-		kfree(queues[i]);
+		kvfree(queues[i]);
 
 	kfree(queues);
 
@@ -651,7 +654,7 @@ static inline void ptr_ring_cleanup(stru
 	if (destroy)
 		while ((ptr = ptr_ring_consume(r)))
 			destroy(ptr);
-	kfree(r->queue);
+	kvfree(r->queue);
 }
 
 #endif /* _LINUX_PTR_RING_H  */