| Message ID | 20200519053019.48376-1-christian.gmeiner@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] drm/etnaviv: fix perfmon domain interation | expand |
Am Dienstag, den 19.05.2020, 07:30 +0200 schrieb Christian Gmeiner: > The GC860 has one GPU device which has a 2d and 3d core. In this case > we want to expose perfmon information for both cores. > > The driver has one array which contains all possible perfmon domains > with some meta data - doms_meta. Here we can see that for the GC860 > two elements of that array are relevant: > > doms_3d: is at index 0 in the doms_meta array with 8 perfmon domains > doms_2d: is at index 1 in the doms_meta array with 1 perfmon domain > > The userspace driver wants to get a list of all perfmon domains and > their perfmon signals. This is done by iterating over all domains and > their signals. If the userspace driver wants to access the domain with > id 8 the kernel driver fails and returns invalid data from doms_3d with > and invalid offset. > > This results in: > Unable to handle kernel paging request at virtual address 00000000 > > On such a device it is not possible to use the userspace driver at all. > > The fix for this off-by-one error is quite simple. > > Reported-by: Paul Cercueil <paul@crapouillou.net> > Tested-by: Paul Cercueil <paul@crapouillou.net> > Fixes: ed1dd899baa3 ("drm/etnaviv: rework perfmon query infrastructure") > Cc: stable@vger.kernel.org > Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com> Thanks, applied to etnaviv/fixes. Regards, Lucas > --- > drivers/gpu/drm/etnaviv/etnaviv_perfmon.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/etnaviv/etnaviv_perfmon.c b/drivers/gpu/drm/etnaviv/etnaviv_perfmon.c > index e6795bafcbb9..75f9db8f7bec 100644 > --- a/drivers/gpu/drm/etnaviv/etnaviv_perfmon.c > +++ b/drivers/gpu/drm/etnaviv/etnaviv_perfmon.c > @@ -453,7 +453,7 @@ static const struct etnaviv_pm_domain *pm_domain(const struct etnaviv_gpu *gpu, > if (!(gpu->identity.features & meta->feature)) > continue; > > - if (meta->nr_domains < (index - offset)) { > + if (index - offset >= meta->nr_domains) { > offset += meta->nr_domains; > continue; > }
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_perfmon.c b/drivers/gpu/drm/etnaviv/etnaviv_perfmon.c index e6795bafcbb9..75f9db8f7bec 100644 --- a/drivers/gpu/drm/etnaviv/etnaviv_perfmon.c +++ b/drivers/gpu/drm/etnaviv/etnaviv_perfmon.c @@ -453,7 +453,7 @@ static const struct etnaviv_pm_domain *pm_domain(const struct etnaviv_gpu *gpu, if (!(gpu->identity.features & meta->feature)) continue; - if (meta->nr_domains < (index - offset)) { + if (index - offset >= meta->nr_domains) { offset += meta->nr_domains; continue; }