[PATCH v2] media: meson: vdec: Fix memory leak in error path of vdec_open

[Nicolas Dufresne]

Hi,

sorry I missed your patch, catching up now.


Le samedi 21 mars 2026 à 12:24 +0530, Anand Moon a écrit :
> The vdec_open and vdec_close functions in the Meson VDEC driver failed
> to release several resources, leading to memory leaks and potential
> use-after-free scenarios.
> 
> This patch addresses:
> - Missing v4l2_ctrl_handler_free() in both the close path and error
>   exit of the open path, preventing control memory leaks.
> - A leak of the M2M context if vdec_init_ctrls() failed.
> 
> The error labels in vdec_open() have been reordered to ensure a proper
> Last-In-First-Out (LIFO) teardown of all initialized resources.
> 
> This was identified via kmemleak:
> unreferenced object 0xffff0000205d6878 (size 8):
>   comm "v4l_id", pid 5289, jiffies 4294938580
>   hex dump (first 8 bytes):
>     40 d2 49 18 00 00 ff ff                          @.I.....
>   backtrace (crc d3204599):
>     kmemleak_alloc+0xc8/0xf0
>     __kvmalloc_node_noprof+0x60c/0x850
>     v4l2_ctrl_handler_init_class+0x1b4/0x2e8 [videodev]
>     vdec_open+0x1f4/0x788 [meson_vdec]
>     v4l2_open+0x144/0x460 [videodev]
>     chrdev_open+0x1ac/0x500
>     do_dentry_open+0x3f0/0xfe8
>     vfs_open+0x68/0x320
>     do_open+0x2d8/0x9a8
>     path_openat+0x1d0/0x4f0
>     do_filp_open+0x190/0x380
>     do_sys_openat2+0xf8/0x1b0
>     __arm64_sys_openat+0x13c/0x1e8
>     invoke_syscall+0xdc/0x268
>     el0_svc_common.constprop.0+0x178/0x258
>     do_el0_svc+0x4c/0x70
> 
> Cc: Nicolas Dufresne <nicolas at ndufresne.ca>
> Fixes: 3e7f51bd9607 ("media: meson: add v4l2 m2m video decoder driver")
> Signed-off-by: Anand Moon <linux.amoon at gmail.com>
> ---
> v1: https://lore.kernel.org/all/20260304100557.126488-1-linux.amoon@gmail.com/
>    tried to address the issue reported by Nicolas
>    improve the commit message.
> ---
>  drivers/staging/media/meson/vdec/vdec.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/staging/media/meson/vdec/vdec.c
> b/drivers/staging/media/meson/vdec/vdec.c
> index 4b77ec1af5a76..3a5e4ebe0b34c 100644
> --- a/drivers/staging/media/meson/vdec/vdec.c
> +++ b/drivers/staging/media/meson/vdec/vdec.c
> @@ -877,7 +877,7 @@ static int vdec_open(struct file *file)
>  	if (IS_ERR(sess->m2m_dev)) {
>  		dev_err(dev, "Fail to v4l2_m2m_init\n");
>  		ret = PTR_ERR(sess->m2m_dev);
> -		goto err_free_sess;
> +		goto err_m2m_release;

If m2m_dev creation failed, why do you want to call v4l2_m2m_release() ?

>  	}
>  
>  	sess->m2m_ctx = v4l2_m2m_ctx_init(sess->m2m_dev, sess,
> m2m_queue_init);
> @@ -889,7 +889,7 @@ static int vdec_open(struct file *file)
>  
>  	ret = vdec_init_ctrls(sess);
>  	if (ret)
> -		goto err_m2m_release;
> +		goto err_m2m_ctx_release;
>  
>  	sess->pixfmt_cap = formats[0].pixfmts_cap[0];
>  	sess->fmt_out = &formats[0];
> @@ -913,9 +913,11 @@ static int vdec_open(struct file *file)
>  
>  	return 0;
>  
> +err_m2m_ctx_release:
> +	v4l2_m2m_ctx_release(sess->m2m_ctx);
>  err_m2m_release:
>  	v4l2_m2m_release(sess->m2m_dev);
> -err_free_sess:
> +	v4l2_ctrl_handler_free(&sess->ctrl_handler);
>  	kfree(sess);
>  	return ret;
>  }
> @@ -926,6 +928,7 @@ static int vdec_close(struct file *file)
>  
>  	v4l2_m2m_ctx_release(sess->m2m_ctx);
>  	v4l2_m2m_release(sess->m2m_dev);
> +	v4l2_ctrl_handler_free(&sess->ctrl_handler);
>  	v4l2_fh_del(&sess->fh, file);
>  	v4l2_fh_exit(&sess->fh);
>  
> 
> base-commit: a0c83177734ab98623795e1ba2cf4b72c23de5e7
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