Patch "ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE" has been added to the 4.9-stable tree

Patch "ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ptr_ring-fail-early-if-queue-occupies-more-than-kmalloc_max_size.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 6e6e41c3112276288ccaf80c70916779b84bb276 Mon Sep 17 00:00:00 2001
From: Jason Wang <jasowang@redhat.com>
Date: Fri, 9 Feb 2018 17:45:49 +0800
Subject: ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE

From: Jason Wang <jasowang@redhat.com>

commit 6e6e41c3112276288ccaf80c70916779b84bb276 upstream.

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

---
 include/linux/ptr_ring.h |    2 ++
 1 file changed, 2 insertions(+)

--- a/include/linux/ptr_ring.h
+++ b/include/linux/ptr_ring.h
@@ -351,6 +351,8 @@ static inline void *ptr_ring_consume_bh(
 
 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);
 }
 


Patches currently in stable-queue which might be from jasowang@redhat.com are

queue-4.9/vhost-use-mutex_lock_nested-in-vhost_dev_lock_vqs.patch
queue-4.9/ptr_ring-fail-early-if-queue-occupies-more-than-kmalloc_max_size.patch