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Date: Thu, 21 Dec 2017 16:55:10 +0800
From: Xishi Qiu <qiuxishi@huawei.com>
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Subject: [RFC] does ioremap() cause memory leak?
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To: Toshi Kani <toshi.kani@hp.com>, "H. Peter Anvin" <hpa@zytor.com>, Thomas
 Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>
Cc: LKML <linux-kernel@vger.kernel.org>, Linux MM <linux-mm@kvack.org>, Xishi Qiu <qiuxishi@huawei.com>

When we use iounmap() to free the mapping, it calls unmap_vmap_area() to clear page table,
but do not free the memory of page table, right?

So when use ioremap() to mapping another area(incluce the area before), it may use
large mapping(e.g. ioremap_pmd_enabled()), so the original page table memory(e.g. pte memory)
will be lost, it cause memory leak, right?

Thanks,
Xishi Qiu

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CC: LKML <linux-kernel@vger.kernel.org>, Linux MM <linux-mm@kvack.org>,
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Subject: [RFC] does ioremap() cause memory leak?
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When we use iounmap() to free the mapping, it calls unmap_vmap_area() to clear page table,
but do not free the memory of page table, right?

So when use ioremap() to mapping another area(incluce the area before), it may use
large mapping(e.g. ioremap_pmd_enabled()), so the original page table memory(e.g. pte memory)
will be lost, it cause memory leak, right?

Thanks,
Xishi Qiu