[LU-5525] ASSERTION( new_lock->l_readers + new_lock->l_writers == 0 ) failed

• Type: Bug
• Resolution: Duplicate
• Priority: Critical
• Labels: llnl
• Environment: MDS node, Lustre 2.4.2-14chaos, ZFS OBD
• Severity: 3
• Assignee: Bruno Faccini (Inactive)
• Reporter: Christopher Morrone (Inactive)

Description

After upgrading to lustre 2.4.2-14chaos (see github.com/chaos/lustre), we soon hit the following assertion on one of our MDS nodes:

mdt_handler.c:3652:mdt_intent_lock_replace()) ASSERTION( new_lock->l_readers + new_lock->l_writers == 0 ) failed

Perhaps most significantly, this tag of our lustre tree includes the patch entitled:

LU-4584 mdt: ensure orig lock is found in hash upon resend

James Simmons reported this assertion when he tested the LU-4584 patch, but the Bruno made the evaluation that the assertion was unrelated to the patch.

Whether it is related or not, we need to fix the problem.

Issue Links

• is related to: LU-5632 ldlm_lock_addref()) ASSERTION( lock != ((void *)0) )
• is related to: LU-4584 Lock revocation process fails consistently
• is related to: LU-3428 Fix 'uninitialized variables' errors

Comments

[Christopher Morrone (Inactive)]

Looks like a bug. You can work around it by using --with-downstream-release:

$ sh autogen.sh
$ ./configure --with-downstream-release=14chaos --disable-liblustre
$ make rpms

If you are trying to reproduce what we see, we use zfs not ldiskfs.

Also, is reproduction likely to be an effective approach to this problem? What do we know about the code, and how do we intend to reproduce the issue?

[Bruno Faccini (Inactive)]

I 1st cloned the chaos git, then selected the 2.4.2-14chaos tag.
And then I applied the/our usual procedure described at "https://wiki.hpdd.intel.com/pages/viewpage.action?pageId=8126821", to generate a ldiskfs-based (sorry I forgot to mention this ...) Server build, and get these error during the "make rpms" step :

...............

Wrote: /home/bruno.faccini/kernel/rpmbuild/SRPMS/lustre-iokit-1.4.0-1.src.rpm
make[1]: Leaving directory `/home/bruno.faccini/lustre-chaos/lustre-iokit'
rpmbuilddir=`mktemp -t -d lustre-build-$USER-XXXXXXXX`; \
        make  \
                rpmbuilddir="$rpmbuilddir" \
                rpm-local || exit 1; \
        rpmbuild \
                --define "_tmppath $rpmbuilddir/TMP" \
                --define "_topdir $rpmbuilddir" \
                --define "build_src_rpm 1" \
                --define "dist %{nil}" \
        -ts lustre-2.4.2.tar.gz || exit 1; \
        cp $rpmbuilddir/SRPMS/*.src.rpm . || exit 1; \
        rm -f -R $rpmbuilddir
make[1]: Entering directory `/home/bruno.faccini/lustre-chaos'
make[1]: Leaving directory `/home/bruno.faccini/lustre-chaos'
error: Macro %rel_down has empty body
error: Macro %rel_build has empty body
error: line 96: Empty tag: Release:
make: *** [srpm] Error 1

So I suspect I don't use the right procedure for your tree since we don't have such "rpmbuilddir" variable/macro in our build infrastructure, which plays with/changes "_topdir" setting ...

[Christopher Morrone (Inactive)]

But now I encounter issues during the make step, Chris, do you use special tricks to build from your source tree ??

Maybe? Could you be more specific about the commands you issued and the problem that you saw? If you had trouble in the liblustre part, try adding --disable-liblustre to the configure command line.

[Bruno Faccini (Inactive)]

Chris,
Please, can you help+answer me about my previous request and detail any specific/procedure to build from LLNL source tree/git ?

[Bruno Faccini (Inactive)]

James,
It's too bad that at the time of this crash you ran with a Lustre debug mask made of only "D_IOCTL+D_NETERROR+D_WANING+D_ERROR+D_EMERG+D_HA+D_CONFIG+D_CONSOLE" and which did not contain at least "D_RPCTRACE+D_DLMTRACE" in addition ... That would have greatly helped to navigate in the crash-dump.

[Bruno Faccini (Inactive)]

But now I encounter issues during the make step, Chris, do you use special tricks to build from your source tree ??

[Bruno Faccini (Inactive)]

Ok, found that 2.6.32-431.3.1 kernel is compatible with 2.4.2-14chaos kernel patches ...

[Christopher Morrone (Inactive)]

I wanted to ask you if you tried to run your LU-4584 reproducer against it already ?

Yes. The LU-4584 patch did appear to help with the evictions on unlink.

[James A Simmons]

I can report I don't see this issue with 2.5 servers. I see another problem instead.

[Bruno Faccini (Inactive)]

Chris, can you help and tell me the kernel version you use/build with 2.4.2-14chaos, I am having problems when patching the 2.6.32-358.23.2 kernel version we use to build our latest b2_4/2.4.3-RC1 branch/tag.

[James A Simmons]

Oops, you are right. I saw this problem with our 2.4 image which did contain the LU-4584 patch. Sorry for the confusion. I pushed the proper debug rpms this time.