[SRU,Zesty,1/1] pstore: Fix flags to enable dumps on powerpc

From: Ankit Kumar <ankit@linux.vnet.ibm.com>

BugLink: http://bugs.launchpad.net/bugs/1691045

After commit c950fd6f201a kernel registers pstore write based on flag set.
Pstore write for powerpc is broken as flags(PSTORE_FLAGS_DMESG) is not set for
powerpc architecture. On panic, kernel doesn't write message to
/fs/pstore/dmesg*(Entry doesn't gets created at all).

This patch enables pstore write for powerpc architecture by setting
PSTORE_FLAGS_DMESG flag.

Fixes: c950fd6f201a ("pstore: Split pstore fragile flags")
Cc: stable@vger.kernel.org # v4.9+
Signed-off-by: Ankit Kumar <ankit@linux.vnet.ibm.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
(cherry picked from commit 041939c1ec54208b42f5cd819209173d52a29d34)
Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>
---
 arch/powerpc/kernel/nvram_64.c | 1 +
 1 file changed, 1 insertion(+)

On 02/06/17 16:37, Joseph Salisbury wrote:
> From: Ankit Kumar <ankit@linux.vnet.ibm.com>
> 
> BugLink: http://bugs.launchpad.net/bugs/1691045
> 
> After commit c950fd6f201a kernel registers pstore write based on flag set.
> Pstore write for powerpc is broken as flags(PSTORE_FLAGS_DMESG) is not set for
> powerpc architecture. On panic, kernel doesn't write message to
> /fs/pstore/dmesg*(Entry doesn't gets created at all).
> 
> This patch enables pstore write for powerpc architecture by setting
> PSTORE_FLAGS_DMESG flag.
> 
> Fixes: c950fd6f201a ("pstore: Split pstore fragile flags")
> Cc: stable@vger.kernel.org # v4.9+
> Signed-off-by: Ankit Kumar <ankit@linux.vnet.ibm.com>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> (cherry picked from commit 041939c1ec54208b42f5cd819209173d52a29d34)
> Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>
> ---
>  arch/powerpc/kernel/nvram_64.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/powerpc/kernel/nvram_64.c b/arch/powerpc/kernel/nvram_64.c
> index d5e2b83..021db31 100644
> --- a/arch/powerpc/kernel/nvram_64.c
> +++ b/arch/powerpc/kernel/nvram_64.c
> @@ -561,6 +561,7 @@ static ssize_t nvram_pstore_read(u64 *id, enum pstore_type_id *type,
>  static struct pstore_info nvram_pstore_info = {
>  	.owner = THIS_MODULE,
>  	.name = "nvram",
> +	.flags = PSTORE_FLAGS_DMESG,
>  	.open = nvram_pstore_open,
>  	.read = nvram_pstore_read,
>  	.write = nvram_pstore_write,
> 

This is a tested upstream cherry pick that fixes the issue and has
limited scope and hence limited regression potential.

Looks good, thanks Joe,

Acked-by: Colin Ian King <colin.king@canonical.com>

On Fri, Jun 02, 2017 at 11:37:33AM -0400, Joseph Salisbury wrote:
> From: Ankit Kumar <ankit@linux.vnet.ibm.com>
> 
> BugLink: http://bugs.launchpad.net/bugs/1691045
> 
> After commit c950fd6f201a kernel registers pstore write based on flag set.
> Pstore write for powerpc is broken as flags(PSTORE_FLAGS_DMESG) is not set for
> powerpc architecture. On panic, kernel doesn't write message to
> /fs/pstore/dmesg*(Entry doesn't gets created at all).
> 
> This patch enables pstore write for powerpc architecture by setting
> PSTORE_FLAGS_DMESG flag.
> 
> Fixes: c950fd6f201a ("pstore: Split pstore fragile flags")
> Cc: stable@vger.kernel.org # v4.9+
> Signed-off-by: Ankit Kumar <ankit@linux.vnet.ibm.com>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> (cherry picked from commit 041939c1ec54208b42f5cd819209173d52a29d34)
> Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>

Clean cherry pick, simple fix.

Acked-by: Seth Forshee <seth.forshee@canonical.com>

Artful and unstable already have this fix.

Applied on zesty/master-next branch. Thanks.