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Message-ID: <a612e9d4560aa3827114339b1ea92f0181550eca.camel@redhat.com>
Date: Wed, 16 Aug 2023 16:47:12 -0400
From: Lyude Paul <lyude@...hat.com>
To: Karol Herbst <kherbst@...hat.com>, linux-kernel@...r.kernel.org
Cc: Ben Skeggs <bskeggs@...hat.com>, dri-devel@...ts.freedesktop.org,
nouveau@...ts.freedesktop.org, Borislav Petkov <bp@...en8.de>,
Takashi Iwai <tiwai@...e.de>
Subject: Re: [PATCH] drm/nouveau/disp: fix use-after-free in error handling
of nouveau_connector_create
Reviewed-by: Lyude Paul <lyude@...hat.com>
On Mon, 2023-08-14 at 16:49 +0200, Karol Herbst wrote:
> We can't simply free the connector after calling drm_connector_init on it.
> We need to clean up the drm side first.
>
> It might not fix all regressions from 2b5d1c29f6c4 ("drm/nouveau/disp:
> PIOR DP uses GPIO for HPD, not PMGR AUX interrupts"), but at least it
> fixes a memory corruption in error handling related to that commit.
>
> Link: https://lore.kernel.org/lkml/20230806213107.GFZNARG6moWpFuSJ9W@fat_crate.local/
> Fixes: 95983aea8003 ("drm/nouveau/disp: add connector class")
> Signed-off-by: Karol Herbst <kherbst@...hat.com>
> ---
> drivers/gpu/drm/nouveau/nouveau_connector.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c
> index a2e0033e8a260..622f6eb9a8bfd 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_connector.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
> @@ -1408,8 +1408,7 @@ nouveau_connector_create(struct drm_device *dev,
> ret = nvif_conn_ctor(&disp->disp, nv_connector->base.name, nv_connector->index,
> &nv_connector->conn);
> if (ret) {
> - kfree(nv_connector);
> - return ERR_PTR(ret);
> + goto drm_conn_err;
> }
>
> ret = nvif_conn_event_ctor(&nv_connector->conn, "kmsHotplug",
> @@ -1426,8 +1425,7 @@ nouveau_connector_create(struct drm_device *dev,
> if (ret) {
> nvif_event_dtor(&nv_connector->hpd);
> nvif_conn_dtor(&nv_connector->conn);
> - kfree(nv_connector);
> - return ERR_PTR(ret);
> + goto drm_conn_err;
> }
> }
> }
> @@ -1475,4 +1473,9 @@ nouveau_connector_create(struct drm_device *dev,
>
> drm_connector_register(connector);
> return connector;
> +
> +drm_conn_err:
> + drm_connector_cleanup(connector);
> + kfree(nv_connector);
> + return ERR_PTR(ret);
> }
--
Cheers,
Lyude Paul (she/her)
Software Engineer at Red Hat
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