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Message-ID: <89ba4c7a-42d2-5412-2367-cc1cffc1117b@gmail.com>
Date: Wed, 24 Mar 2021 22:49:58 +0300
From: Dmitry Osipenko <digetx@...il.com>
To: Minchan Kim <minchan@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>
Cc: linux-mm <linux-mm@...ck.org>, LKML <linux-kernel@...r.kernel.org>,
gregkh@...uxfoundation.org, surenb@...gle.com, joaodias@...gle.com,
jhubbard@...dia.com, willy@...radead.org
Subject: Re: [PATCH] mm: cma: fix corruption cma_sysfs_alloc_pages_count
24.03.2021 22:43, Dmitry Osipenko пишет:
> 24.03.2021 22:20, Minchan Kim пишет:
>> static int __init cma_sysfs_init(void)
>> {
>> - int i = 0;
>> + struct kobject *cma_kobj_root;
>> + struct cma_kobject *cma_kobj;
>> struct cma *cma;
>> + unsigned int i;
>
>> while (--i >= 0) {
>
> Do you realize that this doesn't work anymore?
>
>> cma = &cma_areas[i];
>> - kobject_put(&cma->stat->kobj);
>> - }
>>
>> - kfree(cma_stats);
>> - kobject_put(cma_kobj);
>> + kobject_put(&cma->cma_kobj->kobj);
>> + kfree(cma->cma_kobj);
>
> Freeing a null pointer?
>
>> + cma->cma_kobj = NULL;
>> + }
>> + kobject_put(cma_kobj_root);
>
Please try to simulate the errors and check that error path is working
properly in the next version.
Alternatively, we could remove the cma_kobj_release entirely, like Greg
suggested previously, and then don't care about cleaning up at all.
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