From: Vivek Goyal <vgoyal@redhat.com>
To: linux kernel mailing list <linux-kernel@vger.kernel.org>
Cc: Kay Sievers <kay@vrfy.org>,
Andrew Morton <akpm@linux-foundation.org>,
Kexec Mailing List <kexec@lists.infradead.org>,
"Eric W. Biederman" <ebiederm@xmission.com>
Subject: [PATCH] printk: Export struct log size and member offsets through vmcoreinfo
Date: Wed, 18 Jul 2012 13:18:12 -0400 [thread overview]
Message-ID: <20120718171812.GC21746@redhat.com> (raw)
There are tools like makedumpfile and vmcore-dmesg which can extract
kernel log buffer from vmcore. Since we introduced structured logging,
that functionality is broken. Now user space tools need to know about
"struct log" and offsets of various fields to be able to parse struct
log data and extract text message or dictonary.
This patch exports some of the fields.
Currently I am not exporting log "level" info as that is a bitfield and
offsetof() bitfields can't be calculated. But if people start asking for
log level info in the output then we probably either need to seprate
out "level" or use bit shift operations for flags and level.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
kernel/printk.c | 9 +++++++++
1 file changed, 9 insertions(+)
Index: linux-2.6/kernel/printk.c
===================================================================
--- linux-2.6.orig/kernel/printk.c 2012-07-20 14:02:38.213581253 -0400
+++ linux-2.6/kernel/printk.c 2012-07-20 14:02:42.004581438 -0400
@@ -646,6 +646,15 @@ void log_buf_kexec_setup(void)
VMCOREINFO_SYMBOL(log_buf_len);
VMCOREINFO_SYMBOL(log_first_idx);
VMCOREINFO_SYMBOL(log_next_idx);
+ /*
+ * Export struct log size and field offsets. User space tools can
+ * parse it and detect any changes to structure down the line.
+ */
+ VMCOREINFO_STRUCT_SIZE(log);
+ VMCOREINFO_OFFSET(log, ts_nsec);
+ VMCOREINFO_OFFSET(log, len);
+ VMCOREINFO_OFFSET(log, text_len);
+ VMCOREINFO_OFFSET(log, dict_len);
}
#endif
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
WARNING: multiple messages have this Message-ID (diff)
From: Vivek Goyal <vgoyal@redhat.com>
To: linux kernel mailing list <linux-kernel@vger.kernel.org>
Cc: Kexec Mailing List <kexec@lists.infradead.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Andrew Morton <akpm@linux-foundation.org>,
Kay Sievers <kay@vrfy.org>
Subject: [PATCH] printk: Export struct log size and member offsets through vmcoreinfo
Date: Wed, 18 Jul 2012 13:18:12 -0400 [thread overview]
Message-ID: <20120718171812.GC21746@redhat.com> (raw)
There are tools like makedumpfile and vmcore-dmesg which can extract
kernel log buffer from vmcore. Since we introduced structured logging,
that functionality is broken. Now user space tools need to know about
"struct log" and offsets of various fields to be able to parse struct
log data and extract text message or dictonary.
This patch exports some of the fields.
Currently I am not exporting log "level" info as that is a bitfield and
offsetof() bitfields can't be calculated. But if people start asking for
log level info in the output then we probably either need to seprate
out "level" or use bit shift operations for flags and level.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
kernel/printk.c | 9 +++++++++
1 file changed, 9 insertions(+)
Index: linux-2.6/kernel/printk.c
===================================================================
--- linux-2.6.orig/kernel/printk.c 2012-07-20 14:02:38.213581253 -0400
+++ linux-2.6/kernel/printk.c 2012-07-20 14:02:42.004581438 -0400
@@ -646,6 +646,15 @@ void log_buf_kexec_setup(void)
VMCOREINFO_SYMBOL(log_buf_len);
VMCOREINFO_SYMBOL(log_first_idx);
VMCOREINFO_SYMBOL(log_next_idx);
+ /*
+ * Export struct log size and field offsets. User space tools can
+ * parse it and detect any changes to structure down the line.
+ */
+ VMCOREINFO_STRUCT_SIZE(log);
+ VMCOREINFO_OFFSET(log, ts_nsec);
+ VMCOREINFO_OFFSET(log, len);
+ VMCOREINFO_OFFSET(log, text_len);
+ VMCOREINFO_OFFSET(log, dict_len);
}
#endif
next reply other threads:[~2012-07-18 17:18 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-18 17:18 Vivek Goyal [this message]
2012-07-18 17:18 ` [PATCH] printk: Export struct log size and member offsets through vmcoreinfo Vivek Goyal
2012-07-18 17:27 ` Kay Sievers
2012-07-18 17:27 ` Kay Sievers
2012-07-18 17:56 ` Vivek Goyal
2012-07-18 17:56 ` Vivek Goyal
2012-07-19 9:38 ` Kay Sievers
2012-07-19 9:38 ` Kay Sievers
2012-07-19 13:57 ` Vivek Goyal
2012-07-19 13:57 ` Vivek Goyal
2012-07-19 14:08 ` Vivek Goyal
2012-07-19 14:08 ` Vivek Goyal
2012-07-20 9:23 ` Kay Sievers
2012-07-20 9:23 ` Kay Sievers
2012-07-20 9:50 ` Eric W. Biederman
2012-07-20 9:50 ` Eric W. Biederman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20120718171812.GC21746@redhat.com \
--to=vgoyal@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=ebiederm@xmission.com \
--cc=kay@vrfy.org \
--cc=kexec@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.