linux-kernel - [PATCH 1/3] pstore: Adjust buffer size for compression for smaller registered buffers

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20130911120639.27730.8671.stgit@aruna-ThinkPad-T420>
Date:	Wed, 11 Sep 2013 17:37:00 +0530
From:	Aruna Balakrishnaiah <aruna@...ux.vnet.ibm.com>
To:	linuxppc-dev@...abs.org, tony.luck@...el.com, seiji.aguchi@....com,
	linux-kernel@...r.kernel.org, keescook@...omium.org
Cc:	jkenisto@...ux.vnet.ibm.com, mahesh@...ux.vnet.ibm.com,
	cbouatmailru@...il.com, ananth@...ibm.com, ccross@...roid.com
Subject: [PATCH 1/3] pstore: Adjust buffer size for compression for smaller
 registered buffers

When backends (ex: efivars) have smaller registered buffers, the big_oops_buf
is quite too big for them as number of repeated occurences in the text captured
will be less. Patch takes care of adjusting the buffer size based on the
registered buffer size. cmpr values has been arrived after doing experiments with
plain text for buffers of size 1k - 4k (Smaller the buffer size repeated occurence
will be less) and with sample crash log for buffers ranging from 4k - 10k.

Reported-by: Seiji Aguchi <seiji.aguchi@....com>
Signed-off-by: Aruna Balakrishnaiah <aruna@...ux.vnet.ibm.com>
---
 fs/pstore/platform.c |   23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 4ffb7ab..4efaa75 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -195,8 +195,29 @@ error:
 static void allocate_buf_for_compression(void)
 {
 	size_t size;
+	size_t cmpr;
+
+	switch (psinfo->bufsize) {
+	/* buffer range for efivars */
+	case 1000 ... 2000:
+		cmpr = 56;
+		break;
+	case 2001 ... 3000:
+		cmpr = 54;
+		break;
+	case 3001 ... 3999:
+		cmpr = 52;
+		break;
+	/* buffer range for nvram, erst */
+	case 4000 ... 10000:
+		cmpr = 48;
+		break;
+	default:
+		cmpr = 60;
+		break;
+	}
 
-	big_oops_buf_sz = (psinfo->bufsize * 100) / 45;
+	big_oops_buf_sz = (psinfo->bufsize * 100) / cmpr;
 	big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
 	if (big_oops_buf) {
 		size = max(zlib_deflate_workspacesize(WINDOW_BITS, MEM_LEVEL),

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/