linux-kernel - Re: [PATCH 2/2] ubi: ubi_init: Fix missed ubiblock cleanup in error handling path

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Date: Thu, 11 Apr 2024 00:10:55 +0100
From: Daniel Golle <daniel@...rotopia.org>
To: Zhihao Cheng <chengzhihao1@...wei.com>
Cc: richard@....at, linux-mtd@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] ubi: ubi_init: Fix missed ubiblock cleanup in error
 handling path

Hi!

On Wed, Apr 10, 2024 at 03:40:33PM +0800, Zhihao Cheng wrote:
> The ubiblock_init called by ubi_init will register device number, but
> device number is not released in error handling path of ubi_init when
> ubi is loaded by inserting module (eg. attaching failure), which leads
> to subsequent ubi_init calls failed by running out of device number
> (dmesg shows that "__register_blkdev: failed to get major for ubiblock").
> Fix it by invoking ubiblock_exit() in corresponding error handling path.

Thank you for taking care of this issue.

See my comment inline below:

> 
> Fixes: 927c145208b0 ("mtd: ubi: attach from device tree")
> Signed-off-by: Zhihao Cheng <chengzhihao1@...wei.com>
> ---
>  drivers/mtd/ubi/build.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
> index 7f95fd7968a8..354517194099 100644
> --- a/drivers/mtd/ubi/build.c
> +++ b/drivers/mtd/ubi/build.c
> @@ -1380,12 +1380,13 @@ static int __init ubi_init(void)
>  	if (ubi_is_module()) {
>  		err = ubi_init_attach();
>  		if (err)
> -			goto out_mtd_notifier;
> +			goto out_block_exit;
>  	}
>  
>  	return 0;
>  
> -out_mtd_notifier:
> +out_block_exit:
> +	ubiblock_exit();

I believe that this call is the reason for the section mismatch we
are seeing on Intel's kernel test builds:

https://lore.kernel.org/oe-kbuild-all/202404110656.wLLc5mHR-lkp@intel.com/

Also note that Ben Hutchings has supplied a more complete and imho
better solution for this problem, which yet still suffers from the
same problem (calling __exit function from __init function which
results in section mismatch).


>  	unregister_mtd_user(&ubi_mtd_notifier);
>  out_debugfs:
>  	ubi_debugfs_exit();
> -- 
> 2.39.2
>