** Description changed:
[impact]
programs using libqb logging exit due to failed assertion on qb log init
[test case]
test program:
#include <qb/qblog.h>
QB_LOG_INIT_DATA(test);
int main(int argc, char* argv[])
{
return 0;
}
compile and run:
$ gcc -flto -D_GNU_SOURCE -o test test.c -lqb -ldl
/usr/bin/ld: warning:
/usr/lib/gcc/x86_64-linux-gnu/9/../../../x86_64-linux-gnu/libqb.so contains
output sections; did you forget -T?
$ ./test
test: test.c:4: test: Assertion `"implicit callsite section is observable,
otherwise target's and/or libqb's build is at fault, preventing reliable
logging" && work_s1 != NULL && work_s2 != NULL' failed.
Aborted (core dumped)
Note the error is slightly different when compiling without lto:
$ gcc -D_GNU_SOURCE -o test test.c -lqb -ldl
/usr/bin/ld: warning:
/usr/lib/gcc/x86_64-linux-gnu/9/../../../x86_64-linux-gnu/libqb.so contains
output sections; did you forget -T?
$ ./test
test: test.c:4: test: Assertion `"implicit callsite section is populated,
otherwise target's build is at fault, preventing reliable logging" &&
QB_ATTR_SECTION_START != QB_ATTR_SECTION_STOP' failed.
Aborted (core dumped)
[regression potential]
any regression would likely involve problems during logging using the
libqb logging functions, which could include failure to log or even
program exit and/or crash.
+
+ additionally, altering of build flags (namely
+ -DQB_KILL_ATTRIBUTE_SECTION) removes some symbols from pacemaker
+ libraries (please see the debdiffs for the full list of them). Those
+ seem to be previously defined by macros (resolved in the end to
+ QB_LOG_INIT_DATA) and used internally by libqb for logging purposes. If
+ there was anything using those symbols build time or runtime missing
+ symbols may be reported.
[scope]
this appears to be needed only for focal; the issue seems to be an
interaction between the focal version of binutils and some linker
"magic" that libqb used in the focal version.
The upstream libqb removed/replaced that linker "magic" after the version in
focal, so this should not affect groovy or later. However, the fix changes the
ABI and thus isn't appropriate for SRUing.
https://github.com/ClusterLabs/libqb/pull/322
The libqb code in bionic does not include the linker "magic" and so does
not have this problem.
[other info]
related debian binutils bug report:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=923246
related gcc bug report:
https://sourceware.org/bugzilla/show_bug.cgi?id=24276
however, those appear to only have changed binutils to ignore the issue
to allow the build to stop failing.
The libqb docs do contain two suggestions to possibly work around this
bug, specifically using either -l:libqb.so.0 or
-DQB_KILL_ATTRIBUTE_SECTION, or both. Either or both approaches do help
with the simple test case, but more testing is needed that actually
exercises the log functionality to make sure nothing else breaks.
$ gcc -flto -D_GNU_SOURCE -o test test.c -lqb -ldl
/usr/bin/ld: warning:
/usr/lib/gcc/x86_64-linux-gnu/9/../../../x86_64-linux-gnu/libqb.so contains
output sections; did you forget -T?
$ ./test
test: test.c:4: test: Assertion `"implicit callsite section is observable,
otherwise target's and/or libqb's build is at fault, preventing reliable
logging" && work_s1 != NULL && work_s2 != NULL' failed.
Aborted (core dumped)
$ gcc -flto -D_GNU_SOURCE -o test test.c -l:libqb.so.0 -ldl
$ ./test
$ gcc -flto -DQB_KILL_ATTRIBUTE_SECTION -D_GNU_SOURCE -o test test.c -lqb -ldl
/usr/bin/ld: warning:
/usr/lib/gcc/x86_64-linux-gnu/9/../../../x86_64-linux-gnu/libqb.so contains
output sections; did you forget -T?
$ ./test
[original description]
When a clustered node is detected as failed the remaining node tries to
fence the resources. When using pacemaker with gfs2 on an lvm2 logical
volume dlm_controld calls out to dlm_stonith to release any locks held.
Due to a build issue with the version of libqb that pacemaker is
compiled against, the call to QB_LOG_INIT_DATA which is #defined to
CRM_TRACE_INIT_DATA, fails with an assertion. This prevents the lock
manager from releasing any held locks on the failed node.
At this point the gfs2 filesystem cannot be accessed and after any
resource timeouts are met, the resource is marked as failed.
Calling dlm_stonith by hand with the data that is passed to it by
dlm_controld shows the assertion.
root@u2004-1:~# /usr/sbin/dlm_stonith -n 2 -t 1612361398
dlm_stonith: utils.c:57: common: Assertion `"implicit callsite section is
observable, otherwise target's and/or libqb's build is at fault, preventing
reliable logging" && work_s1 != NULL && work_s2 != NULL' failed.
It would appear that the code in libqb is over aggressive on the sanity
checking, or assumes that QB_LOG_INIT_DATA will only be called by the
library. External programs such as pacemaker that end up calling
CRM_TRACE_INIT_DATA will suffer the same assertion.
This patch from clusterlabs is an attempt to resolve the assertion, but
is still not sufficient.
https://lists.clusterlabs.org/pipermail/users/2018-February/023614.html
Taking out the assertion in <qb/qblog.h> and recompiling pacemaker
appears to be the only way to allow dlm_stonith to work.
journalctl shows dlm_controld keeps trying to get a successful response
from dlm_stonith
Feb 16 13:11:57 u2004-1 dlm_controld[9344]: 4389 fence result 2 pid 26568
result -1 term signal 6
Feb 16 13:11:57 u2004-1 dlm_controld[9344]: 4389 fence status 2 receive -1
from 1 walltime 1613481117 local 4389
Feb 16 13:11:57 u2004-1 dlm_controld[9344]: 4389 fence request 2 pid 26607
nodedown time 1613481102 fence_all dlm_stonith
Feb 16 13:11:58 u2004-1 dlm_controld[9344]: 4391 fence result 2 pid 26607
result -1 term signal 6
Feb 16 13:11:58 u2004-1 dlm_controld[9344]: 4391 fence status 2 receive -1
from 1 walltime 1613481118 local 4391
Feb 16 13:11:58 u2004-1 dlm_controld[9344]: 4391 fence request 2 pid 26637
nodedown time 1613481102 fence_all dlm_stonith
Feb 16 13:12:00 u2004-1 dlm_controld[9344]: 4392 fence result 2 pid 26637
result -1 term signal 6
Feb 16 13:12:00 u2004-1 dlm_controld[9344]: 4392 fence status 2 receive -1
from 1 walltime 1613481120 local 4392
Feb 16 13:12:00 u2004-1 dlm_controld[9344]: 4392 fence request 2 pid 26693
nodedown time 1613481102 fence_all dlm_stonith
....
Calling 'dlm_tool fence_ack 2' by hand immediately releases the dlm
resource locks.
root@u2004-1:~# lsb_release -rd
Description: Ubuntu 20.04 LTS
Release: 20.04
root@u2004-1:~# apt-cache policy pacemaker
pacemaker:
Installed: 2.0.3-3ubuntu4.1
Candidate: 2.0.3-3ubuntu4.1
Version table:
*** 2.0.3-3ubuntu4.1 500
500 http://gb.archive.ubuntu.com/ubuntu focal-updates/main amd64
Packages
500 http://gb.archive.ubuntu.com/ubuntu focal-security/main amd64
Packages
100 /var/lib/dpkg/status
2.0.3-3ubuntu3 500
500 http://gb.archive.ubuntu.com/ubuntu focal/main amd64 Packages
** Changed in: pacemaker (Ubuntu Groovy)
Importance: Undecided => Medium
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https://bugs.launchpad.net/bugs/1915828
Title:
pacemaker fails to release clustered filesystem dlm locks on failover
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