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From:   SeongJae Park <sj38.park@gmail.com>
To:     SeongJae Park <sj38.park@gmail.com>
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Subject: Re: [PATCH v27 07/13] mm/damon: Implement a debugfs-based user space interface
Date:   Mon, 12 Apr 2021 11:22:56 +0000
Message-Id: <20210412112256.880-1-sjpark@amazon.de>
In-Reply-To: <20210408134854.31625-8-sj38.park@gmail.com>
Precedence: bulk

From: SeongJae Park <sjpark@amazon.de>

On Thu,  8 Apr 2021 13:48:48 +0000 SeongJae Park <sj38.park@gmail.com> wrote:

> From: SeongJae Park <sjpark@amazon.de>
> 
> DAMON is designed to be used by kernel space code such as the memory
> management subsystems, and therefore it provides only kernel space API.
> That said, letting the user space control DAMON could provide some
> benefits to them.  For example, it will allow user space to analyze
> their specific workloads and make their own special optimizations.
> 
> For such cases, this commit implements a simple DAMON application kernel
> module, namely 'damon-dbgfs', which merely wraps the DAMON api and
> exports those to the user space via the debugfs.
>
[...]
> +/*
> + * Functions for the initialization
> + */
> +
> +static int __init damon_dbgfs_init(void)
> +{
> +	int rc;
> +
> +	dbgfs_ctxs = kmalloc(sizeof(*dbgfs_ctxs), GFP_KERNEL);
> +	if (!dbgfs_ctxs) {
> +		pr_err("%s: dbgfs ctxs alloc failed\n", __func__);
> +		return -ENOMEM;
> +	}
> +	dbgfs_ctxs[0] = dbgfs_new_ctx();
> +	if (!dbgfs_ctxs[0]) {
> +		pr_err("%s: dbgfs ctx alloc failed\n", __func__);
> +		return -ENOMEM;

My colleague, Stefan found 'dbgfs_ctxs' is not freed here.  Similar in below
'__damon_dbgfs_init()' failure handling.  I will fix these in the next version.

Reported-by: Stefan Nuernberger <snu@amazon.de>


Thanks,
SeongJae Park

> +	}
> +	dbgfs_nr_ctxs = 1;
> +
> +	rc = __damon_dbgfs_init();
> +	if (rc)
> +		pr_err("%s: dbgfs init failed\n", __func__);
> +
> +	return rc;
> +}
> +
> +module_init(damon_dbgfs_init);
> -- 
> 2.17.1
>