When bailing out due to group_priority_permit() failure, the queue_args
need to be freed. Fix it by rearranging the function to use the
goto-on-error pattern, such that the success case flows straight without
indentation while error cases jump forward to cleanup.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 5f7762042f8a ("drm/panthor: Restrict high priorities on group_create")
Signed-off-by: Jann Horn <jannh@xxxxxxxxxx>
---
testcase:
```
#include <err.h>
#include <fcntl.h>
#include <stddef.h>
#include <sys/ioctl.h>
#include <drm/panthor_drm.h>
#define SYSCHK(x) ({ \
typeof(x) __res = (x); \
if (__res == (typeof(x))-1) \
err(1, "SYSCHK(" #x ")"); \
__res; \
})
#define GPU_PATH "/dev/dri/by-path/platform-fb000000.gpu-card"
int main(void) {
int fd = SYSCHK(open(GPU_PATH, O_RDWR));
while (1) {
struct drm_panthor_queue_create qc[16] = {};
struct drm_panthor_group_create gc = {
.queues = {
.stride = sizeof(struct drm_panthor_queue_create),
.count = 16,
.array = (unsigned long)qc
},
.priority = PANTHOR_GROUP_PRIORITY_HIGH+1/*invalid*/
};
ioctl(fd, DRM_IOCTL_PANTHOR_GROUP_CREATE, &gc);
}
}
```
I have tested that without this patch, after running the testcase for a
few seconds and then manually killing it, 2G of RAM in kmalloc-128 have
been leaked. With the patch applied, the memory leak is gone.
(By the way, get_maintainer.pl suggests that I also send this patch to
the general DRM maintainers and the DRM-misc maintainers; looking at
MAINTAINERS, it looks like it is normal that the general DRM maintainers
are listed for everything under drivers/gpu/, but DRM-misc has exclusion
rules for a bunch of drivers but not panthor. I don't know if that is
intentional.)
---
drivers/gpu/drm/panthor/panthor_drv.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/panthor/panthor_drv.c b/drivers/gpu/drm/panthor/panthor_drv.c
index c520f156e2d73f7e735f8bf2d6d8e8efacec9362..815c23cff25f305d884e8e3e263fa22888f7d5ce 100644
--- a/drivers/gpu/drm/panthor/panthor_drv.c
+++ b/drivers/gpu/drm/panthor/panthor_drv.c
@@ -1032,14 +1032,15 @@ static int panthor_ioctl_group_create(struct drm_device *ddev, void *data,
ret = group_priority_permit(file, args->priority);
if (ret)
- return ret;
+ goto out;
ret = panthor_group_create(pfile, args, queue_args);
- if (ret >= 0) {
- args->group_handle = ret;
- ret = 0;
- }
+ if (ret < 0)
+ goto out;
+ args->group_handle = ret;
+ ret = 0;
+out:
kvfree(queue_args);
return ret;
}
---
base-commit: 9f8e716d46c68112484a23d1742d9ec725e082fc
change-id: 20241113-panthor-fix-gcq-bailout-2d9ac36590ed
--
Jann Horn <jannh@xxxxxxxxxx>
