linux-kernel - [PATCH AUTOSEL 5.2 59/85] mm/ioremap: check virtual address alignment while creating huge mappings

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Date:   Fri, 26 Jul 2019 09:39:09 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Anshuman Khandual <anshuman.khandual@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Toshi Kani <toshi.kani@....com>,
        Will Deacon <will.deacon@....com>,
        Chintan Pandya <cpandya@...eaurora.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 5.2 59/85] mm/ioremap: check virtual address alignment while creating huge mappings

From: Anshuman Khandual <anshuman.khandual@....com>

[ Upstream commit 6b95ab4218bfa59bc315105127ffe03aef3b5742 ]

Virtual address alignment is essential in ensuring correct clearing for
all intermediate level pgtable entries and freeing associated pgtable
pages.  An unaligned address can end up randomly freeing pgtable page
that potentially still contains valid mappings.  Hence also check it's
alignment along with existing phys_addr check.

Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
Reviewed-by: Catalin Marinas <catalin.marinas@....com>
Cc: Toshi Kani <toshi.kani@....com>
Cc: Will Deacon <will.deacon@....com>
Cc: Chintan Pandya <cpandya@...eaurora.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 lib/ioremap.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/lib/ioremap.c b/lib/ioremap.c
index 063213685563..a95161d9c883 100644
--- a/lib/ioremap.c
+++ b/lib/ioremap.c
@@ -86,6 +86,9 @@ static int ioremap_try_huge_pmd(pmd_t *pmd, unsigned long addr,
 	if ((end - addr) != PMD_SIZE)
 		return 0;
 
+	if (!IS_ALIGNED(addr, PMD_SIZE))
+		return 0;
+
 	if (!IS_ALIGNED(phys_addr, PMD_SIZE))
 		return 0;
 
@@ -126,6 +129,9 @@ static int ioremap_try_huge_pud(pud_t *pud, unsigned long addr,
 	if ((end - addr) != PUD_SIZE)
 		return 0;
 
+	if (!IS_ALIGNED(addr, PUD_SIZE))
+		return 0;
+
 	if (!IS_ALIGNED(phys_addr, PUD_SIZE))
 		return 0;
 
@@ -166,6 +172,9 @@ static int ioremap_try_huge_p4d(p4d_t *p4d, unsigned long addr,
 	if ((end - addr) != P4D_SIZE)
 		return 0;
 
+	if (!IS_ALIGNED(addr, P4D_SIZE))
+		return 0;
+
 	if (!IS_ALIGNED(phys_addr, P4D_SIZE))
 		return 0;
 
-- 
2.20.1