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| author | Colin Ian King <colin.i.king@gmail.com> | 2022-04-24 19:35:12 +0100 |
|---|---|---|
| committer | Melissa Wen <melissa.srw@gmail.com> | 2022-04-26 11:55:28 -0100 |
| commit | ce7a1ecf3f9f1fccaf67295307614511d8e11b13 (patch) | |
| tree | f082e2eee996ad9ebd25b95a0da6a5b2af925725 | |
| parent | 2deb9739bc133c6a0488f580d90351b72cadf81e (diff) | |
| download | lwn-ce7a1ecf3f9f1fccaf67295307614511d8e11b13.tar.gz lwn-ce7a1ecf3f9f1fccaf67295307614511d8e11b13.zip | |
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: 26a4dc29b74a ("drm/v3d: Expose performance counters to userspace")
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Juan A. Suarez <jasuarez@igalia.com>
Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220424183512.1365683-1-colin.i.king@gmail.com
| -rw-r--r-- | drivers/gpu/drm/v3d/v3d_perfmon.c | 3 |
1 files changed, 2 insertions, 1 deletions
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++) { |