Messages in this thread | | | Date | Mon, 12 Jun 2023 13:22:43 +0200 | Subject | Re: [PATCH] accel/qaic: Fix dereferencing freed memory | From | Christian König <> |
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Am 10.06.23 um 04:12 schrieb Sukrut Bellary: > smatch warning: > drivers/accel/qaic/qaic_data.c:620 qaic_free_object() error: > dereferencing freed memory 'obj->import_attach' > > obj->import_attach is detached and freed using dma_buf_detach(). > But used after free to decrease the dmabuf ref count using > dma_buf_put(). > > Fixes: ff13be830333 ("accel/qaic: Add datapath") > Signed-off-by: Sukrut Bellary <sukrut.bellary@linux.com> > --- > drivers/accel/qaic/qaic_data.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/accel/qaic/qaic_data.c b/drivers/accel/qaic/qaic_data.c > index e42c1f9ffff8..7cba4d680ea8 100644 > --- a/drivers/accel/qaic/qaic_data.c > +++ b/drivers/accel/qaic/qaic_data.c > @@ -613,11 +613,13 @@ static int qaic_gem_object_mmap(struct drm_gem_object *obj, struct vm_area_struc > static void qaic_free_object(struct drm_gem_object *obj) > { > struct qaic_bo *bo = to_qaic_bo(obj); > + struct dma_buf *dmabuf;
Maybe move that variable into the if.
> > if (obj->import_attach) { > /* DMABUF/PRIME Path */ > + dmabuf = obj->import_attach->dmabuf; > dma_buf_detach(obj->import_attach->dmabuf, obj->import_attach); > - dma_buf_put(obj->import_attach->dmabuf); > + dma_buf_put(dmabuf);
I strongly assume you are not using the GEM prime helpers for this?
Christian.
> } else { > /* Private buffer allocation path */ > qaic_free_sgt(bo->sgt);
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