[{"id":3678657,"web_url":"http://patchwork.ozlabs.org/comment/3678657/","msgid":"","list_archive_url":null,"date":"2026-04-17T10:44:52","subject":"Re: [RFC PATCH] hw/display: don't accidentally autofree existing\n virgl resources","submitter":{"id":86526,"url":"http://patchwork.ozlabs.org/api/people/86526/","name":"Manos Pitsidianakis","email":"manos.pitsidianakis@linaro.org"},"content":"On Fri, Apr 17, 2026 at 12:44 PM Alex Bennée wrote:\n>\n> While sanity checking a create blob operation the use of the auto\n> freed res variable could lead to inadvertently freeing an existing\n> blob.\n>\n> Avoid this by in-lining the virtio_gpu_virgl_find_resource() check as\n> the value is not needed anyway.\n>\n> While at it add a comment to the end and use g_steal_pointer to make\n> it clearer the object lifetime exceeds the function bounds if we pass\n> all the checks.\n>\n> Fixes: 7c092f17cce (virtio-gpu: Handle resource blob commands)\n> Signed-off-by: Alex Bennée \n> Cc: qemu-stable@nongnu.org\n> ---\n> hw/display/virtio-gpu-virgl.c | 6 +++---\n> 1 file changed, 3 insertions(+), 3 deletions(-)\n>\n> diff --git a/hw/display/virtio-gpu-virgl.c b/hw/display/virtio-gpu-virgl.c\n> index b7a2d160ddd..add85bd4e61 100644\n> --- a/hw/display/virtio-gpu-virgl.c\n> +++ b/hw/display/virtio-gpu-virgl.c\n> @@ -830,8 +830,7 @@ static void virgl_cmd_resource_create_blob(VirtIOGPU *g,\n> return;\n> }\n>\n> - res = virtio_gpu_virgl_find_resource(g, cblob.resource_id);\n> - if (res) {\n> + if (virtio_gpu_virgl_find_resource(g, cblob.resource_id)) {\n> qemu_log_mask(LOG_GUEST_ERROR, \"%s: resource already exists %d\\n\",\n> __func__, cblob.resource_id);\n> cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_RESOURCE_ID;\n> @@ -884,8 +883,9 @@ static void virgl_cmd_resource_create_blob(VirtIOGPU *g,\n>\n> res->base.dmabuf_fd = info.fd;\n>\n> + /* Now live, cleaned up in virtio_gpu_virgl_resource_unref */\n> QTAILQ_INSERT_HEAD(&g->reslist, &res->base, next);\n> - res = NULL;\n> + g_steal_pointer(&res);\n> }\n>\n> static void virgl_cmd_resource_map_blob(VirtIOGPU *g,\n> --\n> 2.47.3\n>\n\nReviewed-by: Manos Pitsidianakis ","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=linaro.org header.i=@linaro.org header.a=rsa-sha256\n header.s=google header.b=SrE9Qc8S;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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Fri, 17 Apr 2026\n 03:45:19 -0700 (PDT)","MIME-Version":"1.0","References":"<20260417094443.785462-1-alex.bennee@linaro.org>","In-Reply-To":"<20260417094443.785462-1-alex.bennee@linaro.org>","From":"Manos Pitsidianakis ","Date":"Fri, 17 Apr 2026 13:44:52 +0300","X-Gm-Features":"AQROBzDBXmqNyAbsgRoTHa-RBKdXx8C4Gc2zLvKSycMWFoaVsnlaGQV7i0vJYfk","Message-ID":"\n ","Subject":"Re: [RFC PATCH] hw/display: don't accidentally autofree existing\n virgl resources","To":"=?utf-8?q?Alex_Benn=C3=A9e?= ","Cc":"qemu-devel@nongnu.org, qemu-stable@nongnu.org,\n \"Michael S. Tsirkin\" ,\n Akihiko Odaki ,\n Dmitry Osipenko ","Content-Type":"text/plain; charset=\"UTF-8\"","Content-Transfer-Encoding":"quoted-printable","Received-SPF":"pass client-ip=2a00:1450:4864:20::333;\n envelope-from=manos.pitsidianakis@linaro.org; helo=mail-wm1-x333.google.com","X-Spam_score_int":"-20","X-Spam_score":"-2.1","X-Spam_bar":"--","X-Spam_report":"(-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1,\n DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001,\n SPF_PASS=-0.001 autolearn=ham autolearn_force=no","X-Spam_action":"no action","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"qemu development ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"}},{"id":3679156,"web_url":"http://patchwork.ozlabs.org/comment/3679156/","msgid":"","list_archive_url":null,"date":"2026-04-19T23:27:46","subject":"Re: [RFC PATCH] hw/display: don't accidentally autofree existing\n virgl resources","submitter":{"id":83453,"url":"http://patchwork.ozlabs.org/api/people/83453/","name":"Dmitry Osipenko","email":"dmitry.osipenko@collabora.com"},"content":"On 4/17/26 12:44, Alex Bennée wrote:\n> While sanity checking a create blob operation the use of the auto\n> freed res variable could lead to inadvertently freeing an existing\n> blob.\n> \n> Avoid this by in-lining the virtio_gpu_virgl_find_resource() check as\n> the value is not needed anyway.\n> \n> While at it add a comment to the end and use g_steal_pointer to make\n> it clearer the object lifetime exceeds the function bounds if we pass\n> all the checks.\n> \n> Fixes: 7c092f17cce (virtio-gpu: Handle resource blob commands)\n> Signed-off-by: Alex Bennée \n> Cc: qemu-stable@nongnu.org\n> ---\n> hw/display/virtio-gpu-virgl.c | 6 +++---\n> 1 file changed, 3 insertions(+), 3 deletions(-)\n> \n> diff --git a/hw/display/virtio-gpu-virgl.c b/hw/display/virtio-gpu-virgl.c\n> index b7a2d160ddd..add85bd4e61 100644\n> --- a/hw/display/virtio-gpu-virgl.c\n> +++ b/hw/display/virtio-gpu-virgl.c\n> @@ -830,8 +830,7 @@ static void virgl_cmd_resource_create_blob(VirtIOGPU *g,\n> return;\n> }\n> \n> - res = virtio_gpu_virgl_find_resource(g, cblob.resource_id);\n> - if (res) {\n> + if (virtio_gpu_virgl_find_resource(g, cblob.resource_id)) {\n> qemu_log_mask(LOG_GUEST_ERROR, \"%s: resource already exists %d\\n\",\n> __func__, cblob.resource_id);\n> cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_RESOURCE_ID;\n> @@ -884,8 +883,9 @@ static void virgl_cmd_resource_create_blob(VirtIOGPU *g,\n> \n> res->base.dmabuf_fd = info.fd;\n> \n> + /* Now live, cleaned up in virtio_gpu_virgl_resource_unref */\n> QTAILQ_INSERT_HEAD(&g->reslist, &res->base, next);\n> - res = NULL;\n> + g_steal_pointer(&res);\n> }\n> \n> static void virgl_cmd_resource_map_blob(VirtIOGPU *g,\n\nReviewed-by: Dmitry Osipenko ","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=collabora.com header.i=dmitry.osipenko@collabora.com\n header.a=rsa-sha256 header.s=zohomail header.b=MvBKK7BJ;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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Tsirkin\" ,\n Akihiko Odaki ","References":"<20260417094443.785462-1-alex.bennee@linaro.org>","Content-Language":"en-US","From":"Dmitry Osipenko ","In-Reply-To":"<20260417094443.785462-1-alex.bennee@linaro.org>","Content-Type":"text/plain; charset=UTF-8","Content-Transfer-Encoding":"8bit","X-ZohoMailClient":"External","Received-SPF":"pass client-ip=136.143.188.112;\n envelope-from=dmitry.osipenko@collabora.com; helo=sender4-pp-f112.zoho.com","X-Spam_score_int":"-20","X-Spam_score":"-2.1","X-Spam_bar":"--","X-Spam_report":"(-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1,\n DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=-0.01, RCVD_IN_MSPIKE_WL=-0.01,\n SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no","X-Spam_action":"no action","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"qemu development ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"}}]