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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>
hifive-unleashed-5.1
Vitaly Kuznetsov 2015-03-31 11:16:41 -07:00 committed by Greg Kroah-Hartman
parent ba0c444153
commit 797f88c987
1 changed files with 7 additions and 6 deletions
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13
drivers/hv/hv_balloon.c
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@ -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,
struct dm_balloon_response *bl_resp,
int alloc_unit)
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;