gpu: host1x: fix an integer overflow check

Tegra is a 32 bit arch.  On 32 bit systems then size_t is 32 bits so
"total" will never be higher than UINT_MAX because of integer overflows.
We need cast to u64 first before doing the math.

Also the addition earlier:

        unsigned int num_unpins = num_cmdbufs + num_relocs;

That can overflow as well, but I think it's still safe because we check
both "num_cmdbufs" and "num_relocs" again in this test.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

diff --git a/drivers/gpu/host1x/job.c b/drivers/gpu/host1x/job.c
index cc807667d8f16c2f4ac345f28c1965a89e911ee8..18a47f95e90c1dbfd9e937391dc26ebf693e9389 100644 (file)
--- a/drivers/gpu/host1x/job.c
+++ b/drivers/gpu/host1x/job.c
@@ -42,12 +42,12 @@ struct host1x_job *host1x_job_alloc(struct host1x_channel *ch,
 
        /* Check that we're not going to overflow */
        total = sizeof(struct host1x_job) +
-               num_relocs * sizeof(struct host1x_reloc) +
-               num_unpins * sizeof(struct host1x_job_unpin_data) +
-               num_waitchks * sizeof(struct host1x_waitchk) +
-               num_cmdbufs * sizeof(struct host1x_job_gather) +
-               num_unpins * sizeof(dma_addr_t) +
-               num_unpins * sizeof(u32 *);
+               (u64)num_relocs * sizeof(struct host1x_reloc) +
+               (u64)num_unpins * sizeof(struct host1x_job_unpin_data) +
+               (u64)num_waitchks * sizeof(struct host1x_waitchk) +
+               (u64)num_cmdbufs * sizeof(struct host1x_job_gather) +
+               (u64)num_unpins * sizeof(dma_addr_t) +
+               (u64)num_unpins * sizeof(u32 *);
        if (total > ULONG_MAX)
                return NULL;