diff mbox series

[V4] mm/ioremap: Check virtual address alignment while creating huge mappings

Message ID 1557887716-17918-1-git-send-email-anshuman.khandual@arm.com (mailing list archive)
State Mainlined
Commit 6b95ab4218bfa59bc315105127ffe03aef3b5742
Headers show
Series [V4] mm/ioremap: Check virtual address alignment while creating huge mappings | expand

Commit Message

Anshuman Khandual May 15, 2019, 2:35 a.m. UTC
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@arm.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Chintan Pandya <cpandya@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
---
Changes in V4:

- Added similar check for ioremap_try_huge_p4d() as per Toshi Kani

 lib/ioremap.c | 9 +++++++++
 1 file changed, 9 insertions(+)

Comments

Will Deacon May 15, 2019, 9:46 a.m. UTC | #1
On Wed, May 15, 2019 at 08:05:16AM +0530, Anshuman Khandual wrote:
> 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@arm.com>
> Cc: Toshi Kani <toshi.kani@hpe.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Chintan Pandya <cpandya@codeaurora.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> ---
> Changes in V4:
> 
> - Added similar check for ioremap_try_huge_p4d() as per Toshi Kani

Sorry to be a pain, but in future please can you just resend the entire
series as a v4 (after giving it a few days for any other comments to come
in) if you make an update? It's a bit fiddly tracking which replies to which
individual patches need to be picked up, although I'm sure this varies
between maintainers.

No need to do anything this time, but just a small ask for future patches.

Will
Anshuman Khandual May 15, 2019, 10:10 a.m. UTC | #2
On 05/15/2019 03:16 PM, Will Deacon wrote:
> On Wed, May 15, 2019 at 08:05:16AM +0530, Anshuman Khandual wrote:
>> 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@arm.com>
>> Cc: Toshi Kani <toshi.kani@hpe.com>
>> Cc: Andrew Morton <akpm@linux-foundation.org>
>> Cc: Will Deacon <will.deacon@arm.com>
>> Cc: Chintan Pandya <cpandya@codeaurora.org>
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Catalin Marinas <catalin.marinas@arm.com>
>> ---
>> Changes in V4:
>>
>> - Added similar check for ioremap_try_huge_p4d() as per Toshi Kani
> 
> Sorry to be a pain, but in future please can you just resend the entire
> series as a v4 (after giving it a few days for any other comments to come
> in) if you make an update? It's a bit fiddly tracking which replies to which
> individual patches need to be picked up, although I'm sure this varies
> between maintainers.

I wondered for some time about both the ways before landing on this side as it was
pretty minor change. I understand the concern and will follow the suggestion next
time around. If this one requires further update, will make it V5 and carry the
change logs from here.

> 
> No need to do anything this time, but just a small ask for future patches.

Sure will do.
Kani, Toshi May 16, 2019, 6:38 p.m. UTC | #3
On Wed, 2019-05-15 at 08:05 +0530, Anshuman Khandual wrote:
> 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@arm.com>
> Cc: Toshi Kani <toshi.kani@hpe.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Chintan Pandya <cpandya@codeaurora.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> ---
> Changes in V4:
> 
> - Added similar check for ioremap_try_huge_p4d() as per Toshi Kani

Thanks for the update. It looks good to me.

Reviewed-by: Toshi Kani <toshi.kani@hpe.com>

-Toshi
Catalin Marinas June 6, 2019, 1:51 p.m. UTC | #4
On Wed, May 15, 2019 at 08:05:16AM +0530, Anshuman Khandual wrote:
> 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@arm.com>
> Cc: Toshi Kani <toshi.kani@hpe.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Chintan Pandya <cpandya@codeaurora.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Catalin Marinas <catalin.marinas@arm.com>

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>

I guess Andrew can pick this up, otherwise I can queue it through arm64
(there are no arm64 dependencies on this).

Thanks.
diff mbox series

Patch

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;