Note: This bug is displayed in read-only format because
the product is no longer active in Red Hat Bugzilla.
RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.
Cause
Using EVT service from OpenAIS.
Consequence
Sometimes (it's race so really depend on many things like number of cores, load, scheduler, ...) corosync deadlocks.
Fix
Change order of locking.
Result
Corosync doesn't deadlocks any longer.
Created attachment 526640[details]
Proposed patch
Description of problem:
This patch resolves a deadlock between the serialize lock (in
exec/main.c) and the timer lock (in exec/timer.c). I observed this
deadlock happening fairly quickly on a cluster using the EVT service
from OpenAIS. (OpenAIS 1.1.4, Corosync 1.4.1)
In prioritized_timer_thread(), it was grabbing:
1) timer lock
2) serialize lock
In another thread, you have:
1) grab the serialize lock in deliver_fn() of exec/main.c
2) grab the timer lock in corosync_timer_add_duration().
The patch just swaps the locking order in the timer thread.
Version-Release number of selected component (if applicable):
1.4.1
Technical note added. If any revisions are required, please edit the "Technical Notes" field
accordingly. All revisions will be proofread by the Engineering Content Services team.
New Contents:
Cause
Using EVT service from OpenAIS.
Consequence
Sometimes (it's race so really depend on many things like number of cores, load, scheduler, ...) corosync deadlocks.
Fix
Change order of locking.
Result
Corosync doesn't deadlocks any longer.
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/RHBA-2012-0777.html
Created attachment 526640 [details] Proposed patch Description of problem: This patch resolves a deadlock between the serialize lock (in exec/main.c) and the timer lock (in exec/timer.c). I observed this deadlock happening fairly quickly on a cluster using the EVT service from OpenAIS. (OpenAIS 1.1.4, Corosync 1.4.1) In prioritized_timer_thread(), it was grabbing: 1) timer lock 2) serialize lock In another thread, you have: 1) grab the serialize lock in deliver_fn() of exec/main.c 2) grab the timer lock in corosync_timer_add_duration(). The patch just swaps the locking order in the timer thread. Version-Release number of selected component (if applicable): 1.4.1