[PATCH 0/3] CONFIG_DEBUG_SET_MODULE_RONX fixups

[PATCH 0/3] CONFIG_DEBUG_SET_MODULE_RONX fixups

[Laura Abbott]

Hi,

CONFIG_DEBUG_SET_MODULE_RONX is currently non-functional on arm and arm64
because of changes in behavior of is_module_addr. This series fixes
both arm and arm64 to work correctly and corrects a minor bug
related to section alignment in modules.

Laura Abbott (3):
  arm64: Don't use is_module_addr in setting page attributes
  arm: Don't use is_module_addr in setting page attributes
  kernel/module.c: Update debug alignment after symtable generation

 arch/arm/mm/pageattr.c   | 5 ++++-
 arch/arm64/mm/pageattr.c | 5 ++++-
 kernel/module.c          | 2 ++
 3 files changed, 10 insertions(+), 2 deletions(-)

-- 
Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project

[PATCH 0/3] CONFIG_DEBUG_SET_MODULE_RONX fixups

[Laura Abbott]

Hi,

CONFIG_DEBUG_SET_MODULE_RONX is currently non-functional on arm and arm64
because of changes in behavior of is_module_addr. This series fixes
both arm and arm64 to work correctly and corrects a minor bug
related to section alignment in modules.

Laura Abbott (3):
  arm64: Don't use is_module_addr in setting page attributes
  arm: Don't use is_module_addr in setting page attributes
  kernel/module.c: Update debug alignment after symtable generation

 arch/arm/mm/pageattr.c   | 5 ++++-
 arch/arm64/mm/pageattr.c | 5 ++++-
 kernel/module.c          | 2 ++
 3 files changed, 10 insertions(+), 2 deletions(-)

-- 
Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project

[PATCH 1/3] arm64: Don't use is_module_addr in setting page attributes

[Laura Abbott]

The set_memory_* functions currently only support module
addresses. The addresses are validated using is_module_addr.
That function is special though and relies on internal state
in the module subsystem to work properly. At the time of
module initialization and calling set_memory_*, it's too early
for is_module_addr to work properly so it always returns
false. Rather than be subject to the whims of the module state,
just bounds check against the module virtual address range.

Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
---
 arch/arm64/mm/pageattr.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index bb0ea94..1d3ec3d 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -51,7 +51,10 @@ static int change_memory_common(unsigned long addr, int numpages,
 		WARN_ON_ONCE(1);
 	}
 
-	if (!is_module_address(start) || !is_module_address(end - 1))
+	if (start < MODULES_VADDR || start >= MODULES_END)
+		return -EINVAL;
+
+	if (end < MODULES_VADDR || end >= MODULES_END)
 		return -EINVAL;
 
 	data.set_mask = set_mask;
-- 
Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project

[PATCH 1/3] arm64: Don't use is_module_addr in setting page attributes

[Laura Abbott]

The set_memory_* functions currently only support module
addresses. The addresses are validated using is_module_addr.
That function is special though and relies on internal state
in the module subsystem to work properly. At the time of
module initialization and calling set_memory_*, it's too early
for is_module_addr to work properly so it always returns
false. Rather than be subject to the whims of the module state,
just bounds check against the module virtual address range.

Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
---
 arch/arm64/mm/pageattr.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index bb0ea94..1d3ec3d 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -51,7 +51,10 @@ static int change_memory_common(unsigned long addr, int numpages,
 		WARN_ON_ONCE(1);
 	}
 
-	if (!is_module_address(start) || !is_module_address(end - 1))
+	if (start < MODULES_VADDR || start >= MODULES_END)
+		return -EINVAL;
+
+	if (end < MODULES_VADDR || end >= MODULES_END)
 		return -EINVAL;
 
 	data.set_mask = set_mask;
-- 
Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project

Re: [PATCH 1/3] arm64: Don't use is_module_addr in setting page attributes

[Catalin Marinas]

On Wed, Feb 25, 2015 at 02:14:55PM -0800, Laura Abbott wrote:
> 
> The set_memory_* functions currently only support module
> addresses. The addresses are validated using is_module_addr.
> That function is special though and relies on internal state
> in the module subsystem to work properly. At the time of
> module initialization and calling set_memory_*, it's too early
> for is_module_addr to work properly so it always returns
> false. Rather than be subject to the whims of the module state,
> just bounds check against the module virtual address range.
> 
> Signed-off-by: Laura Abbott <lauraa@codeaurora.org>

Not sure which tree this would be merged through, so:

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

I can pick up the arm64 patch and the module.c one with Rusty's ack (as
for the arm one, I think it could go in via rmk's patch system).

-- 
Catalin

[PATCH 1/3] arm64: Don't use is_module_addr in setting page attributes

[Catalin Marinas]

On Wed, Feb 25, 2015 at 02:14:55PM -0800, Laura Abbott wrote:
> 
> The set_memory_* functions currently only support module
> addresses. The addresses are validated using is_module_addr.
> That function is special though and relies on internal state
> in the module subsystem to work properly. At the time of
> module initialization and calling set_memory_*, it's too early
> for is_module_addr to work properly so it always returns
> false. Rather than be subject to the whims of the module state,
> just bounds check against the module virtual address range.
> 
> Signed-off-by: Laura Abbott <lauraa@codeaurora.org>

Not sure which tree this would be merged through, so:

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

I can pick up the arm64 patch and the module.c one with Rusty's ack (as
for the arm one, I think it could go in via rmk's patch system).

-- 
Catalin

[PATCH 2/3] arm: Don't use is_module_addr in setting page attributes

[Laura Abbott]

The set_memory_* functions currently only support module
addresses. The addresses are validated using is_module_addr.
That function is special though and relies on internal state
in the module subsystem to work properly. At the time of
module initialization and calling set_memory_*, it's too early
for is_module_addr to work properly so it always returns
false. Rather than be subject to the whims of the module state,
just bounds check against the module virtual address range.

Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
---
 arch/arm/mm/pageattr.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mm/pageattr.c b/arch/arm/mm/pageattr.c
index 004e35c..cf30daf 100644
--- a/arch/arm/mm/pageattr.c
+++ b/arch/arm/mm/pageattr.c
@@ -49,7 +49,10 @@ static int change_memory_common(unsigned long addr, int numpages,
 		WARN_ON_ONCE(1);
 	}
 
-	if (!is_module_address(start) || !is_module_address(end - 1))
+	if (start < MODULES_VADDR || start >= MODULES_END)
+		return -EINVAL;
+
+	if (end < MODULES_VADDR || start >= MODULES_END)
 		return -EINVAL;
 
 	data.set_mask = set_mask;
-- 
Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project

[PATCH 2/3] arm: Don't use is_module_addr in setting page attributes

[Laura Abbott]

The set_memory_* functions currently only support module
addresses. The addresses are validated using is_module_addr.
That function is special though and relies on internal state
in the module subsystem to work properly. At the time of
module initialization and calling set_memory_*, it's too early
for is_module_addr to work properly so it always returns
false. Rather than be subject to the whims of the module state,
just bounds check against the module virtual address range.

Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
---
 arch/arm/mm/pageattr.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mm/pageattr.c b/arch/arm/mm/pageattr.c
index 004e35c..cf30daf 100644
--- a/arch/arm/mm/pageattr.c
+++ b/arch/arm/mm/pageattr.c
@@ -49,7 +49,10 @@ static int change_memory_common(unsigned long addr, int numpages,
 		WARN_ON_ONCE(1);
 	}
 
-	if (!is_module_address(start) || !is_module_address(end - 1))
+	if (start < MODULES_VADDR || start >= MODULES_END)
+		return -EINVAL;
+
+	if (end < MODULES_VADDR || start >= MODULES_END)
 		return -EINVAL;
 
 	data.set_mask = set_mask;
-- 
Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project

[PATCH 3/3] kernel/module.c: Update debug alignment after symtable generation

[Laura Abbott]

When CONFIG_DEBUG_SET_MODULE_RONX is enabled, the sizes of
module sections are aligned up so appropriate permissions can
be applied. Adjusting for the symbol table may cause them to
become unaligned. Make sure to re-align the sizes afterward.

Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
---
 kernel/module.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/module.c b/kernel/module.c
index b34813f..cc93cf6 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2313,11 +2313,13 @@ static void layout_symtab(struct module *mod, struct load_info *info)
 	info->symoffs = ALIGN(mod->core_size, symsect->sh_addralign ?: 1);
 	info->stroffs = mod->core_size = info->symoffs + ndst * sizeof(Elf_Sym);
 	mod->core_size += strtab_size;
+	mod->core_size = debug_align(mod->core_size);
 
 	/* Put string table section at end of init part of module. */
 	strsect->sh_flags |= SHF_ALLOC;
 	strsect->sh_entsize = get_offset(mod, &mod->init_size, strsect,
 					 info->index.str) | INIT_OFFSET_MASK;
+	mod->init_size = debug_align(mod->init_size);
 	pr_debug("\t%s\n", info->secstrings + strsect->sh_name);
 }
 
-- 
Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project

[PATCH 3/3] kernel/module.c: Update debug alignment after symtable generation

[Laura Abbott]

When CONFIG_DEBUG_SET_MODULE_RONX is enabled, the sizes of
module sections are aligned up so appropriate permissions can
be applied. Adjusting for the symbol table may cause them to
become unaligned. Make sure to re-align the sizes afterward.

Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
---
 kernel/module.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/module.c b/kernel/module.c
index b34813f..cc93cf6 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2313,11 +2313,13 @@ static void layout_symtab(struct module *mod, struct load_info *info)
 	info->symoffs = ALIGN(mod->core_size, symsect->sh_addralign ?: 1);
 	info->stroffs = mod->core_size = info->symoffs + ndst * sizeof(Elf_Sym);
 	mod->core_size += strtab_size;
+	mod->core_size = debug_align(mod->core_size);
 
 	/* Put string table section at end of init part of module. */
 	strsect->sh_flags |= SHF_ALLOC;
 	strsect->sh_entsize = get_offset(mod, &mod->init_size, strsect,
 					 info->index.str) | INIT_OFFSET_MASK;
+	mod->init_size = debug_align(mod->init_size);
 	pr_debug("\t%s\n", info->secstrings + strsect->sh_name);
 }
 
-- 
Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project

Re: [PATCH 3/3] kernel/module.c: Update debug alignment after symtable generation

[Rusty Russell]

Laura Abbott <lauraa@codeaurora.org> writes:
> When CONFIG_DEBUG_SET_MODULE_RONX is enabled, the sizes of
> module sections are aligned up so appropriate permissions can
> be applied. Adjusting for the symbol table may cause them to
> become unaligned. Make sure to re-align the sizes afterward.
>
> Signed-off-by: Laura Abbott <lauraa@codeaurora.org>

Acked-by: Rusty Russell <rusty@rustcorp.com.au>

This won't clash with anything I'm planning, so happy for this to go in
through the arm trees.  CC:stable should be fine if you want too.

Thanks,
Rusty.

> ---
>  kernel/module.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/kernel/module.c b/kernel/module.c
> index b34813f..cc93cf6 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -2313,11 +2313,13 @@ static void layout_symtab(struct module *mod, struct load_info *info)
>  	info->symoffs = ALIGN(mod->core_size, symsect->sh_addralign ?: 1);
>  	info->stroffs = mod->core_size = info->symoffs + ndst * sizeof(Elf_Sym);
>  	mod->core_size += strtab_size;
> +	mod->core_size = debug_align(mod->core_size);
>  
>  	/* Put string table section at end of init part of module. */
>  	strsect->sh_flags |= SHF_ALLOC;
>  	strsect->sh_entsize = get_offset(mod, &mod->init_size, strsect,
>  					 info->index.str) | INIT_OFFSET_MASK;
> +	mod->init_size = debug_align(mod->init_size);
>  	pr_debug("\t%s\n", info->secstrings + strsect->sh_name);
>  }
>  
> -- 
> Qualcomm Innovation Center, Inc.
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/

[PATCH 3/3] kernel/module.c: Update debug alignment after symtable generation

[Rusty Russell]

Laura Abbott <lauraa@codeaurora.org> writes:
> When CONFIG_DEBUG_SET_MODULE_RONX is enabled, the sizes of
> module sections are aligned up so appropriate permissions can
> be applied. Adjusting for the symbol table may cause them to
> become unaligned. Make sure to re-align the sizes afterward.
>
> Signed-off-by: Laura Abbott <lauraa@codeaurora.org>

Acked-by: Rusty Russell <rusty@rustcorp.com.au>

This won't clash with anything I'm planning, so happy for this to go in
through the arm trees.  CC:stable should be fine if you want too.

Thanks,
Rusty.

> ---
>  kernel/module.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/kernel/module.c b/kernel/module.c
> index b34813f..cc93cf6 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -2313,11 +2313,13 @@ static void layout_symtab(struct module *mod, struct load_info *info)
>  	info->symoffs = ALIGN(mod->core_size, symsect->sh_addralign ?: 1);
>  	info->stroffs = mod->core_size = info->symoffs + ndst * sizeof(Elf_Sym);
>  	mod->core_size += strtab_size;
> +	mod->core_size = debug_align(mod->core_size);
>  
>  	/* Put string table section at end of init part of module. */
>  	strsect->sh_flags |= SHF_ALLOC;
>  	strsect->sh_entsize = get_offset(mod, &mod->init_size, strsect,
>  					 info->index.str) | INIT_OFFSET_MASK;
> +	mod->init_size = debug_align(mod->init_size);
>  	pr_debug("\t%s\n", info->secstrings + strsect->sh_name);
>  }
>  
> -- 
> Qualcomm Innovation Center, Inc.
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo at vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH 0/3] CONFIG_DEBUG_SET_MODULE_RONX fixups

[Kees Cook]

On Wed, Feb 25, 2015 at 2:14 PM, Laura Abbott <lauraa@codeaurora.org> wrote:
> Hi,
>
> CONFIG_DEBUG_SET_MODULE_RONX is currently non-functional on arm and arm64
> because of changes in behavior of is_module_addr. This series fixes
> both arm and arm64 to work correctly and corrects a minor bug
> related to section alignment in modules.
>
> Laura Abbott (3):
>   arm64: Don't use is_module_addr in setting page attributes
>   arm: Don't use is_module_addr in setting page attributes
>   kernel/module.c: Update debug alignment after symtable generation
>
>  arch/arm/mm/pageattr.c   | 5 ++++-
>  arch/arm64/mm/pageattr.c | 5 ++++-
>  kernel/module.c          | 2 ++
>  3 files changed, 10 insertions(+), 2 deletions(-)

Thanks for fixing this!

Out of curiosity, which change broke DEBUG_SET_MODULE_RONX ? (i.e.
does this need a CC: stable, and if so, through which release?)

Regardless, consider them:

Reviewed-by: Kees Cook <keescook@chromium.org>

Thanks!

-Kees

-- 
Kees Cook
Chrome OS Security

[PATCH 0/3] CONFIG_DEBUG_SET_MODULE_RONX fixups

[Kees Cook]

On Wed, Feb 25, 2015 at 2:14 PM, Laura Abbott <lauraa@codeaurora.org> wrote:
> Hi,
>
> CONFIG_DEBUG_SET_MODULE_RONX is currently non-functional on arm and arm64
> because of changes in behavior of is_module_addr. This series fixes
> both arm and arm64 to work correctly and corrects a minor bug
> related to section alignment in modules.
>
> Laura Abbott (3):
>   arm64: Don't use is_module_addr in setting page attributes
>   arm: Don't use is_module_addr in setting page attributes
>   kernel/module.c: Update debug alignment after symtable generation
>
>  arch/arm/mm/pageattr.c   | 5 ++++-
>  arch/arm64/mm/pageattr.c | 5 ++++-
>  kernel/module.c          | 2 ++
>  3 files changed, 10 insertions(+), 2 deletions(-)

Thanks for fixing this!

Out of curiosity, which change broke DEBUG_SET_MODULE_RONX ? (i.e.
does this need a CC: stable, and if so, through which release?)

Regardless, consider them:

Reviewed-by: Kees Cook <keescook@chromium.org>

Thanks!

-Kees

-- 
Kees Cook
Chrome OS Security

Re: [PATCH 0/3] CONFIG_DEBUG_SET_MODULE_RONX fixups

[Paolo Pisati]

On Wed, Feb 25, 2015 at 02:17:55PM -0800, Kees Cook wrote:
> On Wed, Feb 25, 2015 at 2:14 PM, Laura Abbott <lauraa@codeaurora.org> wrote:
> > Hi,
> >
> > CONFIG_DEBUG_SET_MODULE_RONX is currently non-functional on arm and arm64
> > because of changes in behavior of is_module_addr. This series fixes
> > both arm and arm64 to work correctly and corrects a minor bug
> > related to section alignment in modules.
> >
> > Laura Abbott (3):
> >   arm64: Don't use is_module_addr in setting page attributes
> >   arm: Don't use is_module_addr in setting page attributes
> >   kernel/module.c: Update debug alignment after symtable generation
> >
> >  arch/arm/mm/pageattr.c   | 5 ++++-
> >  arch/arm64/mm/pageattr.c | 5 ++++-
> >  kernel/module.c          | 2 ++
> >  3 files changed, 10 insertions(+), 2 deletions(-)
> 
> Thanks for fixing this!
> 
> Out of curiosity, which change broke DEBUG_SET_MODULE_RONX ? (i.e.
> does this need a CC: stable, and if so, through which release?)

we need it for 3.19.x too:

without your patches:

root@beaglebone:~# cat /sys/module/bridge/sections/.text
0xbf199000
root@beaglebone:~# cat /sys/module/bridge/sections/.data
0xbf1ae000
root@beaglebone:~# grep -e 0xbf199000 -e 0xbf1ae000 /sys/kernel/debug/kernel_page_tables
0xbf199000-0xbf1b6000         116K     RW x      MEM/CACHED/WBRA

with you patches:

root@beaglebone:~# cat /sys/module/bridge/sections/.text                                                                                   
0xbf191000
root@beaglebone:~# cat /sys/module/bridge/sections/.data
0xbf1a6000
root@beaglebone:~# grep -e 0xbf191000 -e 0xbf1a6000 /sys/kernel/debug/kernel_page_tables                                                   
0xbf191000-0xbf1a2000          68K     ro x      MEM/CACHED/WBRA
0xbf1a2000-0xbf1a6000          16K     ro NX     MEM/CACHED/WBRA
0xbf1a6000-0xbf1ae000          32K     RW NX     MEM/CACHED/WBRA
root@beaglebone:~# uname -a
Linux beaglebone 3.19.0-9-generic #9~RONXFIX SMP Tue Mar 24 10:34:39 UTC 2015
armv7l armv7l armv7l GNU/Linux
root@beaglebone:~#

can you cc: stable@ ?
-- 
bye,
p.

[PATCH 0/3] CONFIG_DEBUG_SET_MODULE_RONX fixups

[Paolo Pisati]

On Wed, Feb 25, 2015 at 02:17:55PM -0800, Kees Cook wrote:
> On Wed, Feb 25, 2015 at 2:14 PM, Laura Abbott <lauraa@codeaurora.org> wrote:
> > Hi,
> >
> > CONFIG_DEBUG_SET_MODULE_RONX is currently non-functional on arm and arm64
> > because of changes in behavior of is_module_addr. This series fixes
> > both arm and arm64 to work correctly and corrects a minor bug
> > related to section alignment in modules.
> >
> > Laura Abbott (3):
> >   arm64: Don't use is_module_addr in setting page attributes
> >   arm: Don't use is_module_addr in setting page attributes
> >   kernel/module.c: Update debug alignment after symtable generation
> >
> >  arch/arm/mm/pageattr.c   | 5 ++++-
> >  arch/arm64/mm/pageattr.c | 5 ++++-
> >  kernel/module.c          | 2 ++
> >  3 files changed, 10 insertions(+), 2 deletions(-)
> 
> Thanks for fixing this!
> 
> Out of curiosity, which change broke DEBUG_SET_MODULE_RONX ? (i.e.
> does this need a CC: stable, and if so, through which release?)

we need it for 3.19.x too:

without your patches:

root at beaglebone:~# cat /sys/module/bridge/sections/.text
0xbf199000
root at beaglebone:~# cat /sys/module/bridge/sections/.data
0xbf1ae000
root at beaglebone:~# grep -e 0xbf199000 -e 0xbf1ae000 /sys/kernel/debug/kernel_page_tables
0xbf199000-0xbf1b6000         116K     RW x      MEM/CACHED/WBRA

with you patches:

root at beaglebone:~# cat /sys/module/bridge/sections/.text                                                                                   
0xbf191000
root at beaglebone:~# cat /sys/module/bridge/sections/.data
0xbf1a6000
root at beaglebone:~# grep -e 0xbf191000 -e 0xbf1a6000 /sys/kernel/debug/kernel_page_tables                                                   
0xbf191000-0xbf1a2000          68K     ro x      MEM/CACHED/WBRA
0xbf1a2000-0xbf1a6000          16K     ro NX     MEM/CACHED/WBRA
0xbf1a6000-0xbf1ae000          32K     RW NX     MEM/CACHED/WBRA
root at beaglebone:~# uname -a
Linux beaglebone 3.19.0-9-generic #9~RONXFIX SMP Tue Mar 24 10:34:39 UTC 2015
armv7l armv7l armv7l GNU/Linux
root at beaglebone:~#

can you cc: stable@ ?
-- 
bye,
p.