[PATCH]pstore: Don't warn if data is uncompressed and type is not PSTORE_TYPE_DMESG

[PATCH]pstore: Don't warn if data is uncompressed and type is not PSTORE_TYPE_DMESG

[Ankit Kumar]

commit 9abdcccc3d5f ("pstore: Extract common arguments into structure") moved
record decompression to function. decompress_record() gets called without
checking type and compressed flag. Warning will be reported if data is
uncompressed. Pstore type PSTORE_TYPE_PPC_OPAL, PSTORE_TYPE_PPC_COMMON doesn't
contain compressed data and warning get printed part of dmesg.

Partial dmesg log:
[   35.848914] pstore: ignored compressed record type 6
[   35.848927] pstore: ignored compressed record type 8

Above warning should not get printed as it is known that data won't be
compressed for above type and it is valid condition.

This patch returns if data is not compressed and print warning only if data is
compressed and type is not PSTORE_TYPE_DMESG.

Reported-by: Anton Blanchard <anton@au1.ibm.com>
Signed-off-by: Ankit Kumar <ankit@linux.vnet.ibm.com>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
---
 fs/pstore/platform.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index d468eec..b304553 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -770,8 +770,11 @@ static void decompress_record(struct pstore_record *record)
 	int unzipped_len;
 	char *decompressed;
 
+	if (!record->compressed)
+		return;
+
 	/* Only PSTORE_TYPE_DMESG support compression. */
-	if (!record->compressed || record->type != PSTORE_TYPE_DMESG) {
+	if (record->type != PSTORE_TYPE_DMESG) {
 		pr_warn("ignored compressed record type %d\n", record->type);
 		return;
 	}
-- 
2.7.4

Re: [PATCH]pstore: Don't warn if data is uncompressed and type is not PSTORE_TYPE_DMESG

[Kees Cook]

On Mon, May 22, 2017 at 10:46 PM, Ankit Kumar <ankit@linux.vnet.ibm.com> wrote:
> commit 9abdcccc3d5f ("pstore: Extract common arguments into structure") moved
> record decompression to function. decompress_record() gets called without
> checking type and compressed flag. Warning will be reported if data is
> uncompressed. Pstore type PSTORE_TYPE_PPC_OPAL, PSTORE_TYPE_PPC_COMMON doesn't
> contain compressed data and warning get printed part of dmesg.
>
> Partial dmesg log:
> [   35.848914] pstore: ignored compressed record type 6
> [   35.848927] pstore: ignored compressed record type 8
>
> Above warning should not get printed as it is known that data won't be
> compressed for above type and it is valid condition.
>
> This patch returns if data is not compressed and print warning only if data is
> compressed and type is not PSTORE_TYPE_DMESG.

Ah, thanks for catching that! Applied for -next.

-Kees

>
> Reported-by: Anton Blanchard <anton@au1.ibm.com>
> Signed-off-by: Ankit Kumar <ankit@linux.vnet.ibm.com>
> Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
> ---
>  fs/pstore/platform.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
> index d468eec..b304553 100644
> --- a/fs/pstore/platform.c
> +++ b/fs/pstore/platform.c
> @@ -770,8 +770,11 @@ static void decompress_record(struct pstore_record *record)
>         int unzipped_len;
>         char *decompressed;
>
> +       if (!record->compressed)
> +               return;
> +
>         /* Only PSTORE_TYPE_DMESG support compression. */
> -       if (!record->compressed || record->type != PSTORE_TYPE_DMESG) {
> +       if (record->type != PSTORE_TYPE_DMESG) {
>                 pr_warn("ignored compressed record type %d\n", record->type);
>                 return;
>         }
> --
> 2.7.4
>



-- 
Kees Cook
Pixel Security