Thank you so much Petri.
Regards
Vidya
-----Original Message-----
From: Latvala, Petri <petri.latvala@xxxxxxxxx>
Sent: Monday, June 21, 2021 3:59 PM
To: Srinivas, Vidya <vidya.srinivas@xxxxxxxxx>
Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx; igt-dev@xxxxxxxxxxxxxxxxxxxxx; markyacoub@xxxxxxxxxxxx; Lin, Charlton <charlton.lin@xxxxxxxxx>
Subject: Re: [PATCH i-g-t] [RFC] tests/drm_read: Fix subtest invalid-buffer
On Fri, May 28, 2021 at 10:02:47AM +0530, Vidya Srinivas wrote:
> Using (void *)-1 directly in read is aborting on chrome systems.
> Following message is seen.
>
> Starting subtest: invalid-buffer
> *** buffer overflow detected ***: terminated Received signal SIGABRT.
> Stack trace:
> Aborted (core dumped)
>
> Patch just adds a pointer variable and uses it in read.
>
> Signed-off-by: Vidya Srinivas <vidya.srinivas@xxxxxxxxx>
> ---
> tests/drm_read.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/tests/drm_read.c b/tests/drm_read.c index
> ccf9d822fd8d..2fdec5be4078 100644
> --- a/tests/drm_read.c
> +++ b/tests/drm_read.c
> @@ -103,10 +103,11 @@ static void teardown(int fd) static void
> test_invalid_buffer(int in) {
> int fd = setup(in, 0);
> + void *add = (void *)-1;
>
> alarm(1);
>
> - igt_assert_eq(read(fd, (void *)-1, 4096), -1);
> + igt_assert_eq(read(fd, add, 4096), -1);
> igt_assert_eq(errno, EFAULT);
>
> teardown(fd);
This looked weird but then I checked what glibc is actually doing. This is FORTIFY_SOURCE in action, and read() checks the buffer with __builtin_object_size() that it has room for the read. Which it can only do here if the address is a literal.
Reviewed-by: Petri Latvala <petri.latvala@xxxxxxxxx>
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