FAILED: patch "[PATCH] arm64: Update PTE_RDONLY in set_pte_at() for PROT_NONE" failed to apply to 4.4-stable tree

FAILED: patch "[PATCH] arm64: Update PTE_RDONLY in set_pte_at() for PROT_NONE" failed to apply to 4.4-stable tree

[gregkh]

The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From fdc69e7df3cb24f18a93192641786e5b7ecd1dfe Mon Sep 17 00:00:00 2001
From: Catalin Marinas <catalin.marinas@arm.com>
Date: Wed, 9 Mar 2016 16:31:29 +0000
Subject: [PATCH] arm64: Update PTE_RDONLY in set_pte_at() for PROT_NONE
 permission

The set_pte_at() function must update the hardware PTE_RDONLY bit
depending on the state of the PTE_WRITE and PTE_DIRTY bits of the given
entry value. However, it currently only performs this for pte_valid()
entries, ignoring PTE_PROT_NONE. The side-effect is that PROT_NONE
mappings would not have the PTE_RDONLY bit set. Without
CONFIG_ARM64_HW_AFDBM, this is not an issue since such PROT_NONE pages
are not accessible anyway.

With commit 2f4b829c625e ("arm64: Add support for hardware updates of
the access and dirty pte bits"), the ptep_set_wrprotect() function was
re-written to cope with automatic hardware updates of the dirty state.
As an optimisation, only PTE_RDONLY is checked to assess the "dirty"
status. Since set_pte_at() does not set this bit for PROT_NONE mappings,
such pages may be considered "dirty" as a result of
ptep_set_wrprotect().

This patch updates the pte_valid() check to pte_present() in
set_pte_at(). It also adds PTE_PROT_NONE to the swap entry bits comment.

Fixes: 2f4b829c625e ("arm64: Add support for hardware updates of the access and dirty pte bits")
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Ganapatrao Kulkarni <gkulkarni@caviumnetworks.com>
Tested-by: Ganapatrao Kulkarni <gkulkarni@cavium.com>
Cc: <stable@vger.kernel.org>

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 7c73b365fcfa..e308807105e2 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -201,7 +201,7 @@ extern void __sync_icache_dcache(pte_t pteval, unsigned long addr);
 static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
 			      pte_t *ptep, pte_t pte)
 {
-	if (pte_valid(pte)) {
+	if (pte_present(pte)) {
 		if (pte_sw_dirty(pte) && pte_write(pte))
 			pte_val(pte) &= ~PTE_RDONLY;
 		else
@@ -626,6 +626,7 @@ extern pgd_t idmap_pg_dir[PTRS_PER_PGD];
  *	bits 0-1:	present (must be zero)
  *	bits 2-7:	swap type
  *	bits 8-57:	swap offset
+ *	bit  58:	PTE_PROT_NONE (must be zero)
  */
 #define __SWP_TYPE_SHIFT	2
 #define __SWP_TYPE_BITS		6

Re: FAILED: patch "[PATCH] arm64: Update PTE_RDONLY in set_pte_at() for PROT_NONE" failed to apply to 4.4-stable tree

[Catalin Marinas]

Hi Greg,

On Sun, Apr 10, 2016 at 01:53:35AM +0100, gregkh@linuxfoundation.org wrote:
> The patch below does not apply to the 4.4-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.
> 
> thanks,
> 
> greg k-h
> 
> ------------------ original commit in Linus's tree ------------------
> 
> From fdc69e7df3cb24f18a93192641786e5b7ecd1dfe Mon Sep 17 00:00:00 2001
> From: Catalin Marinas <catalin.marinas@arm.com>
> Date: Wed, 9 Mar 2016 16:31:29 +0000
> Subject: [PATCH] arm64: Update PTE_RDONLY in set_pte_at() for PROT_NONE
>  permission
> 
> The set_pte_at() function must update the hardware PTE_RDONLY bit
> depending on the state of the PTE_WRITE and PTE_DIRTY bits of the given
> entry value. However, it currently only performs this for pte_valid()
> entries, ignoring PTE_PROT_NONE. The side-effect is that PROT_NONE
> mappings would not have the PTE_RDONLY bit set. Without
> CONFIG_ARM64_HW_AFDBM, this is not an issue since such PROT_NONE pages
> are not accessible anyway.
> 
> With commit 2f4b829c625e ("arm64: Add support for hardware updates of
> the access and dirty pte bits"), the ptep_set_wrprotect() function was
> re-written to cope with automatic hardware updates of the dirty state.
> As an optimisation, only PTE_RDONLY is checked to assess the "dirty"
> status. Since set_pte_at() does not set this bit for PROT_NONE mappings,
> such pages may be considered "dirty" as a result of
> ptep_set_wrprotect().
> 
> This patch updates the pte_valid() check to pte_present() in
> set_pte_at(). It also adds PTE_PROT_NONE to the swap entry bits comment.
> 
> Fixes: 2f4b829c625e ("arm64: Add support for hardware updates of the access and dirty pte bits")
> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
> Reported-by: Ganapatrao Kulkarni <gkulkarni@caviumnetworks.com>
> Tested-by: Ganapatrao Kulkarni <gkulkarni@cavium.com>
> Cc: <stable@vger.kernel.org>

This patch requires another commit that was merged in 4.5. The actual
"Cc: stable" line above should have been:

Cc: <stable@vger.kernel.org> # 4.4.x: ac15bd63bbb2: arm64: Honour !PTE_WRITE in set_pte_at() for kernel mappings

Shall I re-send commit fdc69e7df3cb ("arm64: Update PTE_RDONLY in
set_pte_at() for PROT_NONE permission") with the amended "Cc: stable"
line or you're OK to cherry-pick the dependency?

Thanks.

-- 
Catalin

Re: FAILED: patch "[PATCH] arm64: Update PTE_RDONLY in set_pte_at() for PROT_NONE" failed to apply to 4.4-stable tree

[gregkh]

On Mon, Apr 11, 2016 at 03:48:40PM +0100, Catalin Marinas wrote:
> Hi Greg,
> 
> On Sun, Apr 10, 2016 at 01:53:35AM +0100, gregkh@linuxfoundation.org wrote:
> > The patch below does not apply to the 4.4-stable tree.
> > If someone wants it applied there, or to any other stable or longterm
> > tree, then please email the backport, including the original git commit
> > id to <stable@vger.kernel.org>.
> > 
> > thanks,
> > 
> > greg k-h
> > 
> > ------------------ original commit in Linus's tree ------------------
> > 
> > From fdc69e7df3cb24f18a93192641786e5b7ecd1dfe Mon Sep 17 00:00:00 2001
> > From: Catalin Marinas <catalin.marinas@arm.com>
> > Date: Wed, 9 Mar 2016 16:31:29 +0000
> > Subject: [PATCH] arm64: Update PTE_RDONLY in set_pte_at() for PROT_NONE
> >  permission
> > 
> > The set_pte_at() function must update the hardware PTE_RDONLY bit
> > depending on the state of the PTE_WRITE and PTE_DIRTY bits of the given
> > entry value. However, it currently only performs this for pte_valid()
> > entries, ignoring PTE_PROT_NONE. The side-effect is that PROT_NONE
> > mappings would not have the PTE_RDONLY bit set. Without
> > CONFIG_ARM64_HW_AFDBM, this is not an issue since such PROT_NONE pages
> > are not accessible anyway.
> > 
> > With commit 2f4b829c625e ("arm64: Add support for hardware updates of
> > the access and dirty pte bits"), the ptep_set_wrprotect() function was
> > re-written to cope with automatic hardware updates of the dirty state.
> > As an optimisation, only PTE_RDONLY is checked to assess the "dirty"
> > status. Since set_pte_at() does not set this bit for PROT_NONE mappings,
> > such pages may be considered "dirty" as a result of
> > ptep_set_wrprotect().
> > 
> > This patch updates the pte_valid() check to pte_present() in
> > set_pte_at(). It also adds PTE_PROT_NONE to the swap entry bits comment.
> > 
> > Fixes: 2f4b829c625e ("arm64: Add support for hardware updates of the access and dirty pte bits")
> > Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
> > Reported-by: Ganapatrao Kulkarni <gkulkarni@caviumnetworks.com>
> > Tested-by: Ganapatrao Kulkarni <gkulkarni@cavium.com>
> > Cc: <stable@vger.kernel.org>
> 
> This patch requires another commit that was merged in 4.5. The actual
> "Cc: stable" line above should have been:
> 
> Cc: <stable@vger.kernel.org> # 4.4.x: ac15bd63bbb2: arm64: Honour !PTE_WRITE in set_pte_at() for kernel mappings
> 
> Shall I re-send commit fdc69e7df3cb ("arm64: Update PTE_RDONLY in
> set_pte_at() for PROT_NONE permission") with the amended "Cc: stable"
> line or you're OK to cherry-pick the dependency?

I can cherry-pick, thanks.

greg k-h

Re: FAILED: patch "[PATCH] arm64: Update PTE_RDONLY in set_pte_at() for PROT_NONE" failed to apply to 4.4-stable tree

[gregkh]

On Mon, Apr 11, 2016 at 10:46:07AM -0700, gregkh@linuxfoundation.org wrote:
> On Mon, Apr 11, 2016 at 03:48:40PM +0100, Catalin Marinas wrote:
> > Hi Greg,
> > 
> > On Sun, Apr 10, 2016 at 01:53:35AM +0100, gregkh@linuxfoundation.org wrote:
> > > The patch below does not apply to the 4.4-stable tree.
> > > If someone wants it applied there, or to any other stable or longterm
> > > tree, then please email the backport, including the original git commit
> > > id to <stable@vger.kernel.org>.
> > > 
> > > thanks,
> > > 
> > > greg k-h
> > > 
> > > ------------------ original commit in Linus's tree ------------------
> > > 
> > > From fdc69e7df3cb24f18a93192641786e5b7ecd1dfe Mon Sep 17 00:00:00 2001
> > > From: Catalin Marinas <catalin.marinas@arm.com>
> > > Date: Wed, 9 Mar 2016 16:31:29 +0000
> > > Subject: [PATCH] arm64: Update PTE_RDONLY in set_pte_at() for PROT_NONE
> > >  permission
> > > 
> > > The set_pte_at() function must update the hardware PTE_RDONLY bit
> > > depending on the state of the PTE_WRITE and PTE_DIRTY bits of the given
> > > entry value. However, it currently only performs this for pte_valid()
> > > entries, ignoring PTE_PROT_NONE. The side-effect is that PROT_NONE
> > > mappings would not have the PTE_RDONLY bit set. Without
> > > CONFIG_ARM64_HW_AFDBM, this is not an issue since such PROT_NONE pages
> > > are not accessible anyway.
> > > 
> > > With commit 2f4b829c625e ("arm64: Add support for hardware updates of
> > > the access and dirty pte bits"), the ptep_set_wrprotect() function was
> > > re-written to cope with automatic hardware updates of the dirty state.
> > > As an optimisation, only PTE_RDONLY is checked to assess the "dirty"
> > > status. Since set_pte_at() does not set this bit for PROT_NONE mappings,
> > > such pages may be considered "dirty" as a result of
> > > ptep_set_wrprotect().
> > > 
> > > This patch updates the pte_valid() check to pte_present() in
> > > set_pte_at(). It also adds PTE_PROT_NONE to the swap entry bits comment.
> > > 
> > > Fixes: 2f4b829c625e ("arm64: Add support for hardware updates of the access and dirty pte bits")
> > > Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
> > > Reported-by: Ganapatrao Kulkarni <gkulkarni@caviumnetworks.com>
> > > Tested-by: Ganapatrao Kulkarni <gkulkarni@cavium.com>
> > > Cc: <stable@vger.kernel.org>
> > 
> > This patch requires another commit that was merged in 4.5. The actual
> > "Cc: stable" line above should have been:
> > 
> > Cc: <stable@vger.kernel.org> # 4.4.x: ac15bd63bbb2: arm64: Honour !PTE_WRITE in set_pte_at() for kernel mappings
> > 
> > Shall I re-send commit fdc69e7df3cb ("arm64: Update PTE_RDONLY in
> > set_pte_at() for PROT_NONE permission") with the amended "Cc: stable"
> > line or you're OK to cherry-pick the dependency?
> 
> I can cherry-pick, thanks.

Ok, I take it back, I need a backported version of fdc69e7df3cb for
4.4-stable as it didn't apply cleanly and I don't know the code at all
to be able to do it myself by hand.

Can you provide that backport?

thanks,

greg k-h

Re: FAILED: patch "[PATCH] arm64: Update PTE_RDONLY in set_pte_at() for PROT_NONE" failed to apply to 4.4-stable tree

[Catalin Marinas]

Hi Greg,

On Mon, Apr 18, 2016 at 10:23:28AM +0900, gregkh@linuxfoundation.org wrote:
> On Mon, Apr 11, 2016 at 10:46:07AM -0700, gregkh@linuxfoundation.org wrote:
> > On Mon, Apr 11, 2016 at 03:48:40PM +0100, Catalin Marinas wrote:
> > > This patch requires another commit that was merged in 4.5. The actual
> > > "Cc: stable" line above should have been:
> > > 
> > > Cc: <stable@vger.kernel.org> # 4.4.x: ac15bd63bbb2: arm64: Honour !PTE_WRITE in set_pte_at() for kernel mappings
> > > 
> > > Shall I re-send commit fdc69e7df3cb ("arm64: Update PTE_RDONLY in
> > > set_pte_at() for PROT_NONE permission") with the amended "Cc: stable"
> > > line or you're OK to cherry-pick the dependency?
> > 
> > I can cherry-pick, thanks.
> 
> Ok, I take it back, I need a backported version of fdc69e7df3cb for
> 4.4-stable as it didn't apply cleanly and I don't know the code at all
> to be able to do it myself by hand.
> 
> Can you provide that backport?

As I mentioned in above, it applies cleanly once commit ac15bd63bbb2
("arm64: Honour !PTE_WRITE in set_pte_at() for kernel mappings") is
cherry-picked.

I'll send both commit ac15bd63bbb2 and fdc69e7df3cb as patches to
stable@vger.kernel.org.

Thanks.

-- 
Catalin