Hi Christian,
Le ven. 15 mai 2020 à 12:09, Christian Gmeiner
<christian.gmeiner@xxxxxxxxx> a écrit :
Am Mo., 11. Mai 2020 um 14:38 Uhr schrieb Christian Gmeiner
<christian.gmeiner@xxxxxxxxx>:
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@xxxxxxxxxxxxxxx>
Tested-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
Fixes: ed1dd899baa3 ("drm/etnaviv: rework perfmon query
infrastructure")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Christian Gmeiner <christian.gmeiner@xxxxxxxxx>
---
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..35f7171e779a 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 ((meta->nr_domains - 1) < (index - offset)) {
offset += meta->nr_domains;
continue;
}
--
2.26.2
ping
I'll merge it tomorrow if there's no further feedback.
-Paul
