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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, chen jie <chenjie6@huawei.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Li Zefan <lizefan@huawei.com>, Yang Shi <shy828301@gmail.com>,
        Alexey Dobriyan <adobriyan@gmail.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.4 40/80] mm/memory.c: check return value of ioremap_prot
Date:   Mon,  3 Sep 2018 18:49:18 +0200
Message-Id: <20180903164935.750871255@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: "jie@chenjie6@huwei.com" <jie@chenjie6@huwei.com>

[ Upstream commit 24eee1e4c47977bdfb71d6f15f6011e7b6188d04 ]

ioremap_prot() can return NULL which could lead to an oops.

Link: http://lkml.kernel.org/r/1533195441-58594-1-git-send-email-chenjie6@huawei.com
Signed-off-by: chen jie <chenjie6@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: chenjie <chenjie6@huawei.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 mm/memory.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3701,6 +3701,9 @@ int generic_access_phys(struct vm_area_s
 		return -EINVAL;
 
 	maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot);
+	if (!maddr)
+		return -ENOMEM;
+
 	if (write)
 		memcpy_toio(maddr + offset, buf, len);
 	else