Bug 851269
| Summary: | kernel-debug: enable CONFIG_JBD_DEBUG | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 6 | Reporter: | Thorsten Schlichting <schlichting> |
| Component: | kernel | Assignee: | Eric Sandeen <esandeen> |
| Status: | CLOSED ERRATA | QA Contact: | Eryu Guan <eguan> |
| Severity: | low | Docs Contact: | |
| Priority: | low | ||
| Version: | 6.3 | CC: | bfoster, dchinner, eguan, esandeen, lczerner, rwheeler, zab |
| Target Milestone: | rc | Keywords: | Reopened |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | kernel-2.6.32-395.el6 | Doc Type: | Bug Fix |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2013-11-21 13:29:00 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
This is not a mistake, adding kernel DEBUG config options is not something we do for production kernels. Thanks! Sorry, you misunderstood. I did not ask for the production kernel package, I asked for the kernel-debug package. For example kernel-debug-2.6.32-279.5.1.el6.x86_64.rpm From the package description: ... This variant of the kernel has numerous debugging options enabled. It should only be installed when trying to gather additional information on kernel bugs, as some of these options impact performance noticably. Thorsten, we don't turn on every debug option even in kernel-debug. Can you describe how this option was useful to you? ISTR this generates quite a bit of system log traffic, that may be one reason we left it off. I'm guessing this is related to bug # 850803 / case # 00676179 ? Hi Eric, they didn't tell me the BZ number and I do not have access to 850803, but yes, it's related to case # 00676179. AFAIR there were no extra log messages until enabled by /sys/kernel/debug/jbd/jbd-debug. Shall I check this? Sorry, you are right - jbd_debug doesn't do anything by default unless /sys/kernel/debug/jbd/jbd-debug is set to some threshold. We'll have to consider this one a bit more I think. Since CONFIG_JBD[2]_DEBUG isn't run too often, I want to be sure there is no possibility of regressions if it gets enabled. I'll go ahead & put it back into ASSIGNED for now. This request was evaluated by Red Hat Product Management for inclusion in a Red Hat Enterprise Linux release. Product Management has requested further review of this request by Red Hat Engineering, for potential inclusion in a Red Hat Enterprise Linux release for currently deployed products. This request is not yet committed for inclusion in a release. Patch(es) available on kernel-2.6.32-395.el6 Confirmed CONFIG_JBD_DEBUG and CONFIG_JBD2_DEBUG are "y" on kernel-2.6.32-422.el6, and regression tests on debug kernel show no issues # egrep "JBD.?_DEBUG" /boot/config-2.6.32-422.el6.x86_64.debug CONFIG_JBD_DEBUG=y CONFIG_JBD2_DEBUG=y Set to VERIFIED. Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. http://rhn.redhat.com/errata/RHSA-2013-1645.html |
The kernel-debug package does not contain debug code for ext3 journal replay. grep CONFIG_JBD_DEBUG /boot/config-2.6.32-279.5.1.el6.x86_64.debug # CONFIG_JBD_DEBUG is not set If this is a mistake, please include it in one of the future updates if it doesn't make too much difficulties. It's great to have a kernel quick by hand with debug options enabled, compiling took me several hours. From fs/jbd/Kconfig: config JBD_DEBUG bool "JBD (ext3) debugging support" depends on JBD && DEBUG_FS help If you are using the ext3 journaled file system (or potentially any other file system/device using JBD), this option allows you to enable debugging output while the system is running, in order to help track down any problems you are having. By default the debugging output will be turned off. If you select Y here, then you will be able to turn on debugging with "echo N > /sys/kernel/debug/jbd/jbd-debug", where N is a number between 1 and 5, the higher the number, the more debugging output is generated. To turn debugging off again, do "echo 0 > /sys/kernel/debug/jbd/jbd-debug". BTW: CONFIG_JBD2_DEBUG (for ext4) is also not set....