On Fri, 12 Sep 2025 15:04:18 +0000
Zilin Guan <zilin@xxxxxxxxxx> wrote:
> host_ack_bmp is allocated with vzalloc but is currently freed via
> bitmap_free (which ends up using kfree). This is incorrect as
> allocation and deallocation functions should be paired.
This patch is fixing the freeing of host_seq_bmp, not host_ack_bmp.
Both are allocated with vzalloc(). The same logic applies but the
commit log is incorrect.
> Using mismatched alloc/free may lead to undefined behavior, memory leaks,
> or system instability.
>
> This patch fixes the mismatch by freeing host_ack_bmp with vfree to
> match the vzalloc allocation.
>
Fixes: f232836a9152 ("vfio/pds: Add support for dirty page tracking")
Thanks,
Alex
> Signed-off-by: Zilin Guan <zilin@xxxxxxxxxx>
> ---
> drivers/vfio/pci/pds/dirty.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/vfio/pci/pds/dirty.c b/drivers/vfio/pci/pds/dirty.c
> index c51f5e4c3dd6..481992142f79 100644
> --- a/drivers/vfio/pci/pds/dirty.c
> +++ b/drivers/vfio/pci/pds/dirty.c
> @@ -82,7 +82,7 @@ static int pds_vfio_dirty_alloc_bitmaps(struct pds_vfio_region *region,
>
> host_ack_bmp = vzalloc(bytes);
> if (!host_ack_bmp) {
> - bitmap_free(host_seq_bmp);
> + vfree(host_seq_bmp);
> return -ENOMEM;
> }
>
