From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?Q?Christian_K=c3=b6nig?= Date: Sun, 21 Jun 2020 15:33:01 +0000 Subject: Re: [PATCH][next] drm/mm/selftests: fix unsigned comparison with less than zero Message-Id: List-Id: References: <20200617155959.231740-1-colin.king@canonical.com> In-Reply-To: <20200617155959.231740-1-colin.king@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: Colin King , David Airlie , Daniel Vetter , dri-devel@lists.freedesktop.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Am 17.06.20 um 17:59 schrieb Colin King: > From: Colin Ian King > > Function get_insert_time can return error values that are cast > to a u64. The checks of insert_time1 and insert_time2 check for > the errors but because they are u64 variables the check for less > than zero can never be true. Fix this by casting the value to s64 > to allow of the negative error check to succeed. > > Addresses-Coverity: ("Unsigned compared against 0, no effect") > Fixes: 6e60d5ded06b ("drm/mm: add ig_frag selftest") > Signed-off-by: Colin Ian King Reviewed-by: Christian K=C3=B6nig Going to pick that up for drm-misc-fixes tomorrow. > --- > drivers/gpu/drm/selftests/test-drm_mm.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/selftests/test-drm_mm.c b/drivers/gpu/drm/se= lftests/test-drm_mm.c > index 3846b0f5bae3..671a152a6df2 100644 > --- a/drivers/gpu/drm/selftests/test-drm_mm.c > +++ b/drivers/gpu/drm/selftests/test-drm_mm.c > @@ -1124,12 +1124,12 @@ static int igt_frag(void *ignored) > =20 > insert_time1 =3D get_insert_time(&mm, insert_size, > nodes + insert_size, mode); > - if (insert_time1 < 0) > + if ((s64)insert_time1 < 0) > goto err; > =20 > insert_time2 =3D get_insert_time(&mm, (insert_size * 2), > nodes + insert_size * 2, mode); > - if (insert_time2 < 0) > + if ((s64)insert_time2 < 0) > goto err; > =20 > pr_info("%s fragmented insert of %u and %u insertions took %llu and %= llu nsecs\n",