| Message ID | 20220424183512.1365683-1-colin.i.king@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/v3d: Fix null pointer dereference of pointer perfmon | expand |
On Sun, 2022-04-24 at 19:35 +0100, Colin Ian King wrote: > In the unlikely event that pointer perfmon is null the WARN_ON return > path > occurs after the pointer has already been deferenced. Fix this by > only > dereferencing perfmon after it has been null checked. > Good catch! Reviewed-by: Juan A. Suarez <jasuarez@igalia.com> J.A.
On 04/25, Juan A. Suárez wrote: > On Sun, 2022-04-24 at 19:35 +0100, Colin Ian King wrote: > > In the unlikely event that pointer perfmon is null the WARN_ON return > > path > > occurs after the pointer has already been deferenced. Fix this by > > only > > dereferencing perfmon after it has been null checked. > > > > Good catch! > > Reviewed-by: Juan A. Suarez <jasuarez@igalia.com> Applied to drm-misc-next. Thanks, Melissa > > > J.A. >
diff --git a/drivers/gpu/drm/v3d/v3d_perfmon.c b/drivers/gpu/drm/v3d/v3d_perfmon.c index 0288ef063513..f6a88abccc7d 100644 --- a/drivers/gpu/drm/v3d/v3d_perfmon.c +++ b/drivers/gpu/drm/v3d/v3d_perfmon.c @@ -25,11 +25,12 @@ void v3d_perfmon_start(struct v3d_dev *v3d, struct v3d_perfmon *perfmon) { unsigned int i; u32 mask; - u8 ncounters = perfmon->ncounters; + u8 ncounters; if (WARN_ON_ONCE(!perfmon || v3d->active_perfmon)) return; + ncounters = perfmon->ncounters; mask = GENMASK(ncounters - 1, 0); for (i = 0; i < ncounters; i++) {
In the unlikely event that pointer perfmon is null the WARN_ON return path occurs after the pointer has already been deferenced. Fix this by only dereferencing perfmon after it has been null checked. Fixes: 26a4dc29b74a ("drm/v3d: Expose performance counters to userspace") Signed-off-by: Colin Ian King <colin.i.king@gmail.com> --- drivers/gpu/drm/v3d/v3d_perfmon.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)