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From: Xishi Qiu <qiuxishi@huawei.com>
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>
Subject: [RFC] does ioremap() cause memory leak?
Date: Thu, 21 Dec 2017 16:55:10 +0800	[thread overview]
Message-ID: <5A3B76EE.8020001@huawei.com> (raw)

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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WARNING: multiple messages have this Message-ID (diff)
From: Xishi Qiu <qiuxishi@huawei.com>
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>
Subject: [RFC] does ioremap() cause memory leak?
Date: Thu, 21 Dec 2017 16:55:10 +0800	[thread overview]
Message-ID: <5A3B76EE.8020001@huawei.com> (raw)

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

             reply	other threads:[~2017-12-21  8:55 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-21  8:55 Xishi Qiu [this message]
2017-12-21  8:55 ` [RFC] does ioremap() cause memory leak? Xishi Qiu
2017-12-23  5:32 ` Xishi Qiu
2017-12-23  5:32   ` Xishi Qiu
2017-12-23  5:32   ` Xishi Qiu
2018-01-02  1:39   ` Hanjun Guo
2018-01-02  1:39     ` Hanjun Guo
2018-01-02  1:39     ` Hanjun Guo

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