Re: [PATCH 5/5] block/nvme: Fix memory leak from nvme_init_queue()

[Kevin Wolf <kwolf@redhat.com>]

Am 02.11.2021 um 13:36 hat Philippe Mathieu-Daudé geschrieben:
> On 11/2/21 13:33, Kevin Wolf wrote:
> > Am 07.10.2021 um 15:34 hat Philippe Mathieu-Daudé geschrieben:
> >> On 10/7/21 15:29, Stefan Hajnoczi wrote:
> >>> On Wed, Oct 06, 2021 at 06:49:31PM +0200, Philippe Mathieu-Daudé wrote:
> >>>> nvme_create_queue_pair() allocates resources with qemu_vfio_dma_map(),
> >>>> but we never release them. Do it in nvme_free_queue() which is called
> >>>> from nvme_free_queue_pair().
> >>>>
> >>>> Reported by valgrind:
> >>>>
> >>>>   ==252858== 520,192 bytes in 1 blocks are still reachable in loss record 8,293 of 8,302
> >>>>   ==252858==    at 0x4846803: memalign (vg_replace_malloc.c:1265)
> >>>>   ==252858==    by 0x484691F: posix_memalign (vg_replace_malloc.c:1429)
> >>>>   ==252858==    by 0xB8AFE4: qemu_try_memalign (oslib-posix.c:210)
> >>>>   ==252858==    by 0xA9E315: nvme_create_queue_pair (nvme.c:229)
> >>>>   ==252858==    by 0xAA0125: nvme_init (nvme.c:799)
> >>>>   ==252858==    by 0xAA081C: nvme_file_open (nvme.c:953)
> >>>>   ==252858==    by 0xA23DDD: bdrv_open_driver (block.c:1550)
> >>>>   ==252858==    by 0xA24806: bdrv_open_common (block.c:1827)
> >>>>   ==252858==    by 0xA2889B: bdrv_open_inherit (block.c:3747)
> >>>>   ==252858==    by 0xA28DE4: bdrv_open (block.c:3840)
> >>>>   ==252858==    by 0x9E0F8E: bds_tree_init (blockdev.c:675)
> >>>>   ==252858==    by 0x9E7C74: qmp_blockdev_add (blockdev.c:3551)
> >>>>
> >>>> Fixes: bdd6a90a9e5 ("block: Add VFIO based NVMe driver")
> >>>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> >>>> ---
> >>>>  block/nvme.c | 1 +
> >>>>  1 file changed, 1 insertion(+)
> >>>>
> >>>> diff --git a/block/nvme.c b/block/nvme.c
> >>>> index 6e476f54b9f..903c8ffa060 100644
> >>>> --- a/block/nvme.c
> >>>> +++ b/block/nvme.c
> >>>> @@ -185,6 +185,7 @@ static bool nvme_init_queue(BDRVNVMeState *s, NVMeQueue *q,
> >>>>  
> >>>>  static void nvme_free_queue(BDRVNVMeState *s, NVMeQueue *q)
> >>>>  {
> >>>> +    qemu_vfio_dma_unmap(s->vfio, q->queue);
> >>>>      qemu_vfree(q->queue);
> >>>>  }
> >>>
> >>> I can't figure out the issue. qemu_vfree(q->queue) was already called
> >>> before this patch. How does adding qemu_vfio_dma_unmap() help with the
> >>> valgrind report in the commit description?
> >>
> >> You are right, I think I didn't select the correct record
> >> between the 8302 reported by valgrind. I will revisit, thanks.
> > 
> > Should we still merge (parts of) this series for 6.2? Or does this mean
> > that we don't want it at all?
> 
> Patches #1-4 are cleanups welcome for 6.2 :) However we do not want #5.

Thanks. Patch 4 doesn't seem to make sense without 5 (and definitely not
without rewriting the commit message), but I'm applying patches 1-3.

Kevin