Commit ce7a1ecf authored by Colin Ian King's avatar Colin Ian King Committed by Melissa Wen
Browse files

drm/v3d: Fix null pointer dereference of pointer perfmon 



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: 26a4dc29 ("drm/v3d: Expose performance counters to userspace")
Signed-off-by: default avatarColin Ian King <colin.i.king@gmail.com>
Reviewed-by: default avatarJuan A. Suarez <jasuarez@igalia.com>
Signed-off-by: default avatarMelissa Wen <melissa.srw@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220424183512.1365683-1-colin.i.king@gmail.com
parent 2deb9739

drivers/gpu/drm/v3d/v3d_perfmon.c

+2 −1
Original line number Diff line number Diff line
@@ -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++) {