[PATCH v2] DmaBufAllocator: Avoid syncing with an invalid file descriptor

[Kieran Bingham]

Quoting Milan Zamazal (2025-01-14 09:10:12)
> Harvey Yang <chenghaoyang at chromium.org> writes:
> 
> > As DmaSyncer disables the copy c'tor, the move c'tor will be used
> > instead. This leaves some DmaSyncers with invalid SharedFDs. They should
> > avoid syncing with invalid file descriptors in the d'tor.
> >
> > Fixes: 545046a41e17 ("DmaBufAllocator: Make DmaSyncer non-copyable")
> > Signed-off-by: Harvey Yang <chenghaoyang at chromium.org>
> > Tested-by: Milan Zamazal <mzamazal at redhat.com>
> 
> Reviewed-by: Milan Zamazal <mzamazal at redhat.com>

Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

Will push through CI and merge iff/when it completes.

--
Kieran


> 
> > ---
> >  src/libcamera/dma_buf_allocator.cpp | 7 ++++++-
> >  1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/src/libcamera/dma_buf_allocator.cpp b/src/libcamera/dma_buf_allocator.cpp
> > index a014c3b4263c..d8c62dd67a96 100644
> > --- a/src/libcamera/dma_buf_allocator.cpp
> > +++ b/src/libcamera/dma_buf_allocator.cpp
> > @@ -325,7 +325,12 @@ DmaSyncer::DmaSyncer(SharedFD fd, SyncType type)
> >  
> >  DmaSyncer::~DmaSyncer()
> >  {
> > -     sync(DMA_BUF_SYNC_END);
> > +     /*
> > +      * DmaSyncer might be moved and left with an empty SharedFD.
> > +      * Avoid syncing with an invalid file descriptor in this case.
> > +      */
> > +     if (fd_.isValid())
> > +             sync(DMA_BUF_SYNC_END);
> >  }
> >  
> >  void DmaSyncer::sync(uint64_t step)
>