3:40 p.m.
Hi Dave,
on some distributions (e.g. Ubuntu) crash cannot find the live kernel image
because of a slight mismatch between kt->proc_version and 'strings' output
from namelist file (e.g. /boot/vmlinux-debug-2.6.22-14-generic)
Namely, kt->proc_version is LF-terminated, but there is no LF in 'strings
vmlinux' output.
If I strip LF from the end of kt->proc_version, everything works fine
--- filesys.c.orig 2008-02-28 11:09:10.000000000 -0500
+++ filesys.c 2008-03-13 16:33:02.000000000 -0400
@@ -3689,7 +3689,10 @@
int found;
char command[BUFSIZE];
FILE *pipe;
+ int slen = strlen(string);
+ if (slen && string[slen-1] == '\n')
+ string[slen-1] = '\0';
sprintf(command, "/usr/bin/strings %s", filename);
if ((pipe = popen(command, "r")) == NULL) {
=====================================================================
Regards,
Alex
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------------------------------------------------------------------
Alexandre Sidorenko email: alexs(a)hplinux.canada.hp.com
Global Solutions Engineering: Unix Networking
Hewlett-Packard (Canada)
------------------------------------------------------------------
4:23 p.m.
Alex Sidorenko wrote:
Hi Dave,
on some distributions (e.g. Ubuntu) crash cannot find the live kernel image
because of a slight mismatch between kt->proc_version and 'strings' output
from namelist file (e.g. /boot/vmlinux-debug-2.6.22-14-generic)
Namely, kt->proc_version is LF-terminated, but there is no LF in 'strings
vmlinux' output.
If I strip LF from the end of kt->proc_version, everything works fine
--- filesys.c.orig 2008-02-28 11:09:10.000000000 -0500
+++ filesys.c 2008-03-13 16:33:02.000000000 -0400
@@ -3689,7 +3689,10 @@
int found;
char command[BUFSIZE];
FILE *pipe;
+ int slen = strlen(string);
+ if (slen && string[slen-1] == '\n')
+ string[slen-1] = '\0';
sprintf(command, "/usr/bin/strings %s", filename);
if ((pipe = popen(command, "r")) == NULL) {
=====================================================================
Regards,
Alex
Hi Alex,
Help me out here -- when I run it, both kt->proc_version and the buffer
read from the strings output read by fgets() both have linefeeds.
Are you saying that the fgets() call is stripping the linefeed from
the strings output? The "strings vmlinux" output has to have linefeeds
or else it would be a huge mash of characters.
What am I missing?
Dave
8:11 a.m.
On March 13, 2008 05:23:58 pm Dave Anderson wrote:
Hi Dave,
even though my fix works, explanation was incorrect :-(
Yes, both strings are LF-terminated, but on Ubuntu the string in 'strings'
output has extra information appended at the end.
/proc/version:
Linux version 2.6.22-14-generic (buildd@terranova) (gcc version 4.1.3 20070929
(prerelease) (Ubuntu 4.1.2-16ubuntu2)) #1 SMP Tue Feb 12 07:42:25 UTC 2008
'strings' output:
Linux version 2.6.22-14-generic (buildd@terranova) (gcc version 4.1.3 20070929
(prerelease) (Ubuntu 4.1.2-16ubuntu2)) #1 SMP Tue Feb 12 07:42:25 UTC 2008
(Ubuntu 2.6.22-14.52-generic)
So on Ubuntu there is additional '(Ubuntu 2.6.22-14.52-generic)' after the
string itself.
This is more of the problem we discussed and fixed in
http://www.mail-archive.com/crash-utility%40redhat.com/msg00442.html
Now match_file_string() is used in two places to compare with
kt->proc_version and in one place with
if (!match_file_string(system_map, "D system_utsname", buffer))
Stripping LF makes strstr() find a partial match. This should be OK for
comparisons with /proc/version and I think it's OK for "D system_utsname"
either.
Regards,
Alex
Alex Sidorenko wrote:
> Hi Dave,
>
> on some distributions (e.g. Ubuntu) crash cannot find the live kernel
> image because of a slight mismatch between kt->proc_version and
'strings'
> output from namelist file (e.g. /boot/vmlinux-debug-2.6.22-14-generic)
>
> Namely, kt->proc_version is LF-terminated, but there is no LF in 'strings
> vmlinux' output.
>
> If I strip LF from the end of kt->proc_version, everything works fine
>
> --- filesys.c.orig 2008-02-28 11:09:10.000000000 -0500
> +++ filesys.c 2008-03-13 16:33:02.000000000 -0400
> @@ -3689,7 +3689,10 @@
> int found;
> char command[BUFSIZE];
> FILE *pipe;
> + int slen = strlen(string);
>
> + if (slen && string[slen-1] == '\n')
> + string[slen-1] = '\0';
>
> sprintf(command, "/usr/bin/strings %s", filename);
> if ((pipe = popen(command, "r")) == NULL) {
>
> =====================================================================
>
> Regards,
> Alex
Hi Alex,
Help me out here -- when I run it, both kt->proc_version and the buffer
read from the strings output read by fgets() both have linefeeds.
Are you saying that the fgets() call is stripping the linefeed from
the strings output? The "strings vmlinux" output has to have linefeeds
or else it would be a huge mash of characters.
What am I missing?
Dave
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Global Solutions Engineering: Unix Networking
Hewlett-Packard (Canada)
------------------------------------------------------------------
8:35 a.m.
Alex Sidorenko wrote:
On March 13, 2008 05:23:58 pm Dave Anderson wrote:
Hi Dave,
even though my fix works, explanation was incorrect :-(
Yes, both strings are LF-terminated, but on Ubuntu the string in 'strings'
output has extra information appended at the end.
/proc/version:
Linux version 2.6.22-14-generic (buildd@terranova) (gcc version 4.1.3 20070929
(prerelease) (Ubuntu 4.1.2-16ubuntu2)) #1 SMP Tue Feb 12 07:42:25 UTC 2008
'strings' output:
Linux version 2.6.22-14-generic (buildd@terranova) (gcc version 4.1.3 20070929
(prerelease) (Ubuntu 4.1.2-16ubuntu2)) #1 SMP Tue Feb 12 07:42:25 UTC 2008
(Ubuntu 2.6.22-14.52-generic)
So on Ubuntu there is additional '(Ubuntu 2.6.22-14.52-generic)' after the
string itself.
This is more of the problem we discussed and fixed in
http://www.mail-archive.com/crash-utility%40redhat.com/msg00442.html
Now match_file_string() is used in two places to compare with
kt->proc_version and in one place with
if (!match_file_string(system_map, "D system_utsname", buffer))
Stripping LF makes strstr() find a partial match. This should be OK for
comparisons with /proc/version and I think it's OK for "D system_utsname"
either.
Regards,
Alex
After refreshing my memory banks, I remembered the earlier Ubuntu
inspired patch -- thanks for pulling out the post.
Anyway, since match_file_string() is used by multiple entities, and in
the future a caller may actually want to include the linefeed, it doesn't
seem appropriate to make the change there.
Can you test the attached patch on both a live system and a dumpfile?
It strips the linefeed from the version string when it's initialized,
and makes a couple other minor adjustments, including to the first Ubuntu
patch, which shouldn't be required any more.
Thanks,
Dave
8:58 a.m.
On March 14, 2008 09:35:59 am Dave Anderson wrote:
Anyway, since match_file_string() is used by multiple entities, and
in
the future a caller may actually want to include the linefeed, it doesn't
seem appropriate to make the change there.
Can you test the attached patch on both a live system and a dumpfile?
It strips the linefeed from the version string when it's initialized,
and makes a couple other minor adjustments, including to the first Ubuntu
patch, which shouldn't be required any more.
Hi Dave,
your patch works fine. I agree it is safer to strip directly kt->procversion
as match_file_string() is a general-purpose function and can be eventually
used for something very different.
Regards,
Alex
--
------------------------------------------------------------------
Alexandre Sidorenko email: alexs(a)hplinux.canada.hp.com
Global Solutions Engineering: Unix Networking
Hewlett-Packard (Canada)
------------------------------------------------------------------
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