Re: [Tee-dev] [PATCH] optee: remove address tag in check_mem_type()

On Mon, Oct 12, 2020 at 11:26 AM Volodymyr Babchuk Volodymyr_Babchuk@epam.com wrote:

Before passing 'start' to find_vma() we need to remove tags from it to get sane results.

Signed-off-by: Volodymyr Babchuk volodymyr_babchuk@epam.com

drivers/tee/optee/call.c | 2 ++ 1 file changed, 2 insertions(+)

Would you mind giving a bit more background to this? For example in which contexts this function does or doesn't work as expected? Do you have any special use cases that don't work, etc? This is not a new regression, it's rather a problem we've always had, right?

Thanks, Jens

diff --git a/drivers/tee/optee/call.c b/drivers/tee/optee/call.c index a5afbe6dee68..61420395137b 100644 --- a/drivers/tee/optee/call.c +++ b/drivers/tee/optee/call.c @@ -562,6 +562,8 @@ static int check_mem_type(unsigned long start, size_t num_pages) struct mm_struct *mm = current->mm; int rc;

•   start = untagged_addr(start);
  

•   down_read(&mm->mmap_sem);
    rc = __check_mem_type(find_vma(mm, start),
                          start + num_pages * PAGE_SIZE);
  

-- 2.27.0