[GIT PULL 4/7] intel_th: msu: Fix overflow in shift of an unsigned int

From: Alexander Shishkin
Date: Mon Oct 28 2019 - 03:07:29 EST

From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

The shift of the unsigned int win->nr_blocks by PAGE_SHIFT may
potentially overflow. Note that the intended return of this shift
is expected to be a size_t however the shift is being performed as
an unsigned int. Fix this by casting win->nr_blocks to a size_t
before performing the shift.

Addresses-Coverity: ("Unintentional integer overflow")
Fixes: 615c164da0eb ("intel_th: msu: Introduce buffer interface")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/lkml/20190726113151.8967-1-colin.king@xxxxxxxxxxxxx/
drivers/hwtracing/intel_th/msu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwtracing/intel_th/msu.c b/drivers/hwtracing/intel_th/msu.c
index 201a166fdff5..9dc9ae87b5e5 100644
--- a/drivers/hwtracing/intel_th/msu.c
+++ b/drivers/hwtracing/intel_th/msu.c
@@ -327,7 +327,7 @@ static size_t msc_win_total_sz(struct msc_window *win)
struct msc_block_desc *bdesc = sg_virt(sg);

if (msc_block_wrapped(bdesc))
- return win->nr_blocks << PAGE_SHIFT;
+ return (size_t)win->nr_blocks << PAGE_SHIFT;

size += msc_total_sz(bdesc);
if (msc_block_last_written(bdesc))