[Bug 235282] Re: Every second number disappears in (tiny) dmesg output (in initrd.img)
This was fixed in Intrepid a while back (before hardy-updates, in fact): klibc (1.5.10-1ubuntu1) intrepid; urgency=low * Merge from debian unstable, remaining changes: - Add lpia to the architecture list for klibc-utils-floppy-udeb. -- Kees Cook [EMAIL PROTECTED] Mon, 09 Jun 2008 10:40:21 -0700 klibc (1.5.10-1) unstable; urgency=low * New upstream release (dmesg, nfsmount) - dmesg: fix the stripping of priority codes (closes: #483186) - ubuntu sync rework 11-klibc-run-init-drop-executable-stack.patch - add git fix 12-klibc-avoid-.gitignore-in-the-include-directory.patch -- maximilian attems [EMAIL PROTECTED] Thu, 05 Jun 2008 22:21:44 +0200 ** Changed in: klibc (Ubuntu) Status: Fix Committed = Fix Released -- Every second number disappears in (tiny) dmesg output (in initrd.img) https://bugs.launchpad.net/bugs/235282 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 235282] Re: Every second number disappears in (tiny) dmesg output (in initrd.img)
Copied to hardy-updates. ** Changed in: klibc (Ubuntu Hardy) Status: Fix Committed = Fix Released -- Every second number disappears in (tiny) dmesg output (in initrd.img) https://bugs.launchpad.net/bugs/235282 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 235282] Re: Every second number disappears in (tiny) dmesg output (in initrd.img)
Needs to be fixed in Intrepid ASAP. ** Changed in: klibc (Ubuntu) Target: None = intrepid-alpha-2 -- Every second number disappears in (tiny) dmesg output (in initrd.img) https://bugs.launchpad.net/bugs/235282 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 235282] Re: Every second number disappears in (tiny) dmesg output (in initrd.img)
I've verified that this behavior exists in klibc-util's dmesg in version
1.5.7-4ubuntu3 released in Hardy, and that it is fixed in version
1.5.7-4ubuntu4 in hardy-proposed. I've not otherwise exercised klibc to
verify that there are no regressions.
** Description changed:
Note: An equivalent bug report is filed as Debian Bug#483186 at
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=483186
Every now and then, we come across a machine which is unable to mount
the root filesystem for whatever reasons, and get stuck at the busybox
initrd environment, from which we can run dmesg to diagnostic what went
wrong.
To our dismay, in recent months (or years?), dmesg result come out like
this, with lots of missing numbers. For example, from a test machine
booting Ubuntu 8.04 hardy (with an upgraded kernel):
[0.000] Linux version 2.6.2-1-generic ([EMAIL PROTECTED]) (gcc
version 4.2.3 (Ubuntu 4.2.3-2ubuntu7)) #1 SMP Thu May 2 0:0:4 UTC 20 (Ubuntu
2.6.2-1.2ubuntu6-generic)
[0.000] BIOS-provided physical RAM map:
[0.000] BIOS-e80: - 00e00 (usable)
[0.000] BIOS-e80: 00e00 - 00a00 (reserved)
But it is supposed to look like this:
[0.00] Linux version 2.6.25-1-generic ([EMAIL PROTECTED]) (gcc
version 4.2.3 (Ubuntu 4.2.3-2ubuntu7)) #1 SMP Thu May 22 05:01:49 UTC 2008
(Ubuntu 2.6.25-1.2ubuntu6-generic)
[0.00] BIOS-provided physical RAM map:
[0.00] BIOS-e820: - 0009e000 (usable)
[0.00] BIOS-e820: 0009e000 - 000a (reserved)
This caused quite a bit of problem when we trying to diagnose kernel
oops or panics since the addresses are all wrong.
Initially, we thought it had something to do with memory corruption from
the kernel Oops. But later, we noticed this phenomenon happens even for
cases without a kernel oops, say, perhaps we just got root=/dev/sda7
written wrong.
So, we decided to investigate, and eventually came to the realization
that the dmesg in initrd.img in Ubuntu (and Debian) nowadays come not
from busybox but klibc-utils, and running /usr/lib/klibc/bin/dmesg on a
fully booted system exhibit the same bug.
Checking the source code, we found the code used to strip out [0-7]
that prefixes every kernel message (See klogd(8)) is somewhat incorrect.
So, with a bit of hacking, we got that fixed. :-) A patch is attached.
Just drop it in debian/patches/20_dmesg_dropped-digits.patch and
repackage! :-)
We have verified the output of this fixed dmesg identical to that of
util-linux dmesg.
Further thoughts:
We checked out klibc source using:
git clone git://git.kernel.org/pub/scm/libs/klibc/klibc.git
And noticed it is an upstream bug since dmesg.c was first added on Mon
Aug 20 19:57:50 2007 +0200 as commit
9c5a7acda064daa7482148b5a45ee3b7ed39356c
As to why this bug wasn't discovered sooner... I don't know. Perhaps
very few people use the tiny dmesg in klibc-utils for diagnostic
purposes? And before that, Ubuntu (and Debian) uses the dmesg module in
busybox, which exhibits no such bug?
Cheers,
Anthony Fok anthony dot fok at thizgroup dot com
ThizLinux Software Co., Ltd. - A member of Thiz Technology Group
Debian GNU/Linux Developer
+
+ TESTCASE
+ - ensure klibc-utils is installed
+ $ /usr/lib/klibc/bin/dmesg /tmp/klibc.dmesg
+ $ /bin/dmesg /tmp/bin.dmesg
+ diff -u /tmp/{klibc,bin}.dmesg should show no differences (except for any
additional messages that were emitted between the dmesg invocations)
--
Every second number disappears in (tiny) dmesg output (in initrd.img)
https://bugs.launchpad.net/bugs/235282
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[Bug 235282] Re: Every second number disappears in (tiny) dmesg output (in initrd.img)
** Tags added: verification-done ** Tags removed: verification-needed -- Every second number disappears in (tiny) dmesg output (in initrd.img) https://bugs.launchpad.net/bugs/235282 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 235282] Re: Every second number disappears in (tiny) dmesg output (in initrd.img)
Anthony - it looks like upstream has committed a fix for this issue 'dmesg: fix the stripping of priority codes'. -- Every second number disappears in (tiny) dmesg output (in initrd.img) https://bugs.launchpad.net/bugs/235282 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 235282] Re: Every second number disappears in (tiny) dmesg output (in initrd.img)
SRU Justification: Impact: The klibc-utils dmesg used by initramfs incorrectly strips priority codes, mangling the output such that every other decimal digit is missing. Patch Description: Sync with upstream git://git.kernel.org/pub/scm/libs/klibc/klibc.git commit 15c8d22886f4355539f7f557b7184ffedc0002b9 Patch: attached TEST CASE: See bug description ** Attachment added: dmesg priority code stripping. http://launchpadlibrarian.net/15143793/klibc_1.5.7-4ubuntu4.patch ** Changed in: klibc (Ubuntu) Importance: Undecided = Medium Status: In Progress = Fix Committed Target: None = ubuntu-8.04.1 -- Every second number disappears in (tiny) dmesg output (in initrd.img) https://bugs.launchpad.net/bugs/235282 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 235282] Re: Every second number disappears in (tiny) dmesg output (in initrd.img)
Accepted into -proposed, please test and give feedback here ** Changed in: klibc (Ubuntu) Target: ubuntu-8.04.1 = None ** Changed in: klibc (Ubuntu Hardy) Status: New = Fix Committed ** Tags added: verification-needed -- Every second number disappears in (tiny) dmesg output (in initrd.img) https://bugs.launchpad.net/bugs/235282 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
Re: [Bug 235282] Re: Every second number disappears in (tiny) dmesg output (in initrd.img)
Hello Tim, Yes, upstream author hpa (H. Peter Anvin) happened to be on #etherboot, and he asked me to post the patch on klibc mailing list: http://www.zytor.com/pipermail/klibc/2008-May/002288.html However, someone dislikes the way I wrote it, saying it is if speghetti code. (That's kind of how dmesg.c in util-linux does it though...) http://www.zytor.com/pipermail/klibc/2008-May/002290.html And the marvellous hpa promptly came up with something better, an easier-to-follow state-machine-like approach: http://www.zytor.com/pipermail/klibc/2008-May/002289.html So yes, I'm very happy that hpa is so responsive, and I'm also very glad that you've already dealt with this issue in Ubuntu too. Many thanks, Tim and Steve! :-) Anthony -- Every second number disappears in (tiny) dmesg output (in initrd.img) https://bugs.launchpad.net/bugs/235282 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
Re: [Bug 235282] Re: Every second number disappears in (tiny) dmesg output (in initrd.img)
However, someone dislikes the way I wrote it, saying it is if speghetti code. (That's kind of how dmesg.c in util-linux does it though...) http://www.zytor.com/pipermail/klibc/2008-May/002290.html My bad. That someone is Maximilian Attems, and I just realized he is the Debian maintainer of the klibc package, and he also promptly uploaded a fix too a few days ago. :-) Thanks to Maximilian's comment, we got hpa's own fix, which is much better. :-) Cheers, Anthony -- Every second number disappears in (tiny) dmesg output (in initrd.img) https://bugs.launchpad.net/bugs/235282 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 235282] Re: Every second number disappears in (tiny) dmesg output (in initrd.img)
** Attachment added: Patch to fix klibc-utils dmesg [0-7] stripping algorithm http://launchpadlibrarian.net/14751275/20_dmesg_dropped-digits.patch ** Description changed: Note: An equivalent bug report is filed as Debian Bug#483186 at http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=483186 Every now and then, we come across a machine which is unable to mount the root filesystem for whatever reasons, and get stuck at the busybox initrd environment, from which we can run dmesg to diagnostic what went wrong. To our dismay, in recent months (or years?), dmesg result come out like this, with lots of missing numbers. For example, from a test machine booting Ubuntu 8.04 hardy (with an upgraded kernel): [0.000] Linux version 2.6.2-1-generic ([EMAIL PROTECTED]) (gcc version 4.2.3 (Ubuntu 4.2.3-2ubuntu7)) #1 SMP Thu May 2 0:0:4 UTC 20 (Ubuntu 2.6.2-1.2ubuntu6-generic) [0.000] BIOS-provided physical RAM map: [0.000] BIOS-e80: - 00e00 (usable) [0.000] BIOS-e80: 00e00 - 00a00 (reserved) But it is supposed to look like this: [0.00] Linux version 2.6.25-1-generic ([EMAIL PROTECTED]) (gcc version 4.2.3 (Ubuntu 4.2.3-2ubuntu7)) #1 SMP Thu May 22 05:01:49 UTC 2008 (Ubuntu 2.6.25-1.2ubuntu6-generic) [0.00] BIOS-provided physical RAM map: [0.00] BIOS-e820: - 0009e000 (usable) [0.00] BIOS-e820: 0009e000 - 000a (reserved) This caused quite a bit of problem when we trying to diagnose kernel oops or panics since the addresses are all wrong. Initially, we thought it had something to do with memory corruption from the kernel Oops. But later, we noticed this phenomenon happens even for cases without a kernel oops, say, perhaps we just got root=/dev/sda7 written wrong. So, we decided to investigate, and eventually came to the realization that the dmesg in initrd.img in Ubuntu (and Debian) nowadays come not from busybox but klibc-utils, and running /usr/lib/klibc/bin/dmesg on a fully booted system exhibit the same bug. - Checking the source code, we found the code used to strip out [0-7] that prefixes every kernel message (See klogd(8)) is somewhat incorrect. So, with a bit of hacking, we got that fixed. :-) A patch is attached. Just drop it in debian/patches/20_dmesg_dropped-digits.patch - and repackage! :-) + Checking the source code, we found the code used to strip out [0-7] + that prefixes every kernel message (See klogd(8)) is somewhat incorrect. + So, with a bit of hacking, we got that fixed. :-) A patch is attached. + Just drop it in debian/patches/20_dmesg_dropped-digits.patch and + repackage! :-) We have verified the output of this fixed dmesg identical to that of util-linux dmesg. Further thoughts: We checked out klibc source using: git clone git://git.kernel.org/pub/scm/libs/klibc/klibc.git - And noticed it is an upstream bug since dmesg.c was first added on (Mon - Aug 20 19:57:50 2007 +0200) commit + And noticed it is an upstream bug since dmesg.c was first added on Mon + Aug 20 19:57:50 2007 +0200 as commit 9c5a7acda064daa7482148b5a45ee3b7ed39356c - As to why this bug wasn't discovered sooner... I don't know. Perhaps very few people use the tiny dmesg in klibc-utils for diagnostic - purposes? And before that, Ubuntu (and Debian) uses the dmesg module in busybox, which exhibits no such bug? + As to why this bug wasn't discovered sooner... I don't know. Perhaps + very few people use the tiny dmesg in klibc-utils for diagnostic + purposes? And before that, Ubuntu (and Debian) uses the dmesg module in + busybox, which exhibits no such bug? Cheers, Anthony Fok anthony dot fok at thizgroup dot com ThizLinux Software Co., Ltd. - A member of Thiz Technology Group Debian GNU/Linux Developer ** Tags added: dmesg initrd klibc -- Every second number disappears in (tiny) dmesg output (in initrd.img) https://bugs.launchpad.net/bugs/235282 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 235282] Re: Every second number disappears in (tiny) dmesg output (in initrd.img)
** Changed in: klibc (Ubuntu) Assignee: (unassigned) = Tim Gardner (timg-tpi) Status: New = In Progress -- Every second number disappears in (tiny) dmesg output (in initrd.img) https://bugs.launchpad.net/bugs/235282 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
