[libcamera-devel] [PATCH] qcam: Fix ViewFinder memory leak

[Laurent Pinchart]

Hello,

On Tue, Sep 24, 2019 at 12:51:32PM +0100, Kieran Bingham wrote:
> On 24/09/2019 09:16, Jacopo Mondi wrote:
> > On Mon, Sep 23, 2019 at 02:22:29PM +0100, Kieran Bingham wrote:
> >> When setting the format on the ViewFinder, a new image_ is allocated.
> >> Any change in format deletes the existing allocation, but it is not
> >> cleaned up on shutdown:
> >>
> >> Direct leak of 32 byte(s) in 1 object(s) allocated from:
> >>     #0 0x7f0bf8a7e17f in operator new(unsigned long) (/usr/lib/x86_64-linux-gnu/libasan.so.5+0x10e17f)
> >>     #1 0x564c7205f7b0 in ViewFinder::setFormat(unsigned int, unsigned int, unsigned int) ../src/qcam/viewfinder.cpp:43
> >>     #2 0x564c71fec467 in MainWindow::startCapture() ../src/qcam/main_window.cpp:152
> >>     #3 0x564c71fe6c1a in MainWindow::MainWindow(libcamera::CameraManager*, OptionsParser::Options const&) ../src/qcam/main_window.cpp:40
> >>     #4 0x564c71fdf133 in main ../src/qcam/main.cpp:76
> >>     #5 0x7f0bf5944b6a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x26b6a)
> >>
> >> Provide a ViewFinder destructor, and delete the allocation as
> >> appropriate.
> > 
> > Good catch, but I don't see where the viewfinder gets destroyed in
> > main_window.cpp. How does the newly added destructor gets called?
> 
> Intriguing, the addition of the destructor made the LeakSanitizer
> warning go away, however I believe you are right. There is no explicit
> call to delete the ViewFinder which is created as part of the MainWindow.
> 
> I'll add this, and respin a v2.

No need to, https://doc.qt.io/qt-5/qobject.html#dtor.QObject

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

> >> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> >> ---
> >>  src/qcam/viewfinder.cpp | 5 +++++
> >>  src/qcam/viewfinder.h   | 1 +
> >>  2 files changed, 6 insertions(+)
> >>
> >> diff --git a/src/qcam/viewfinder.cpp b/src/qcam/viewfinder.cpp
> >> index 224a227ddd5b..98a8ab68e5f6 100644
> >> --- a/src/qcam/viewfinder.cpp
> >> +++ b/src/qcam/viewfinder.cpp
> >> @@ -16,6 +16,11 @@ ViewFinder::ViewFinder(QWidget *parent)
> >>  {
> >>  }
> >>
> >> +ViewFinder::~ViewFinder()
> >> +{
> >> +	delete image_;
> >> +}
> >> +
> >>  void ViewFinder::display(const unsigned char *raw, size_t size)
> >>  {
> >>  	converter_.convert(raw, size, image_);
> >> diff --git a/src/qcam/viewfinder.h b/src/qcam/viewfinder.h
> >> index c9ca98913e05..33bdb1460f84 100644
> >> --- a/src/qcam/viewfinder.h
> >> +++ b/src/qcam/viewfinder.h
> >> @@ -17,6 +17,7 @@ class ViewFinder : public QLabel
> >>  {
> >>  public:
> >>  	ViewFinder(QWidget *parent);
> >> +	~ViewFinder();
> >>
> >>  	int setFormat(unsigned int format, unsigned int width,
> >>  		      unsigned int height);

-- 
Regards,

Laurent Pinchart