Commit 797f88c9 authored Mar 31, 2015 by Vitaly Kuznetsov Committed by Greg Kroah-Hartman Apr 03, 2015

Drivers: hv: hv_balloon: correctly handle num_pages>INT_MAX case



balloon_wrk.num_pages is __u32 and it comes from host in struct dm_balloon
where it is also __u32. We, however, use 'int' in balloon_up() and in case
we happen to receive num_pages>INT_MAX request we'll end up allocating zero
pages as 'num_pages < alloc_unit' check in alloc_balloon_pages() will pass.
Change num_pages type to unsigned int.

In real life ballooning request come with num_pages in [512, 32768] range so
this is more a future-proof/cleanup.

Reported-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent ba0c4441

drivers/hv/hv_balloon.c

+7 −6

Original line number	Diff line number	Diff line
		@@ -1081,11 +1081,12 @@ static void free_balloon_pages(struct hv_dynmem_device *dm,



		static int alloc_balloon_pages(struct hv_dynmem_device *dm, int num_pages,
		static unsigned int alloc_balloon_pages(struct hv_dynmem_device *dm,
		unsigned int num_pages,
		struct dm_balloon_response *bl_resp,
		int alloc_unit)
		{
		int i = 0;
		unsigned int i = 0;
		struct page *pg;

		if (num_pages < alloc_unit)
		@@ -1132,8 +1133,8 @@ static int alloc_balloon_pages(struct hv_dynmem_device *dm, int num_pages,

		static void balloon_up(struct work_struct *dummy)
		{
		int num_pages = dm_device.balloon_wrk.num_pages;
		int num_ballooned = 0;
		unsigned int num_pages = dm_device.balloon_wrk.num_pages;
		unsigned int num_ballooned = 0;
		struct dm_balloon_response *bl_resp;
		int alloc_unit;
		int ret;

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