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Cause: A race condition in the internal confdb data storage system would had incorrect mutual exclusion.
Consequence: Corosync would segfault under rare and contrived circumstances.
Fix: The race condition was fixed.
Result: Corosync no longer segfaults.
Created attachment 503906[details]
Patch for first problem
Description of problem:
Problem 1:
in confdb_object_iter result of object_find_create is now properly
checked. object_find_create can return -1 if object doesn't exists.
Without this check, incorrect handle (memory garbage) was directly
passed to object_find_next.
Problem 2:
Following situation could happen:
- process 1 thru confdb creates find handle
- calls find iteration once
- different process 2 deletes object pointed by process 1 iterator
- process 1 calls iteration again ->
object_find_instance->find_child_list is invalid pointer
-> segfault
Now object_find_create creates array of matching object handlers and
object_find_next uses that array together with check for name. This
prevents situation where between steps 2 and 3 new object is created
with different name but sadly with same handler.
Version-Release number of selected component (if applicable):
Corosync master
How reproducible:
Often but it's race so depends on HW, ... Problem 1 is visible in valgrind.
Steps to Reproduce:
One node.
# for i in `seq 1 5`;do (while true;do corosync-objctl -a | grep closed;done)& done
# corosync -f
Actual results:
segfault
Expected results:
no segfault
Additional info:
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: A race condition in the internal confdb data storage system would had incorrect mutual exclusion.
Consequence: Corosync would segfault under rare and contrived circumstances.
Fix: The race condition was fixed.
Result: Corosync no longer segfaults.
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-2011-1515.html
Created attachment 503906 [details] Patch for first problem Description of problem: Problem 1: in confdb_object_iter result of object_find_create is now properly checked. object_find_create can return -1 if object doesn't exists. Without this check, incorrect handle (memory garbage) was directly passed to object_find_next. Problem 2: Following situation could happen: - process 1 thru confdb creates find handle - calls find iteration once - different process 2 deletes object pointed by process 1 iterator - process 1 calls iteration again -> object_find_instance->find_child_list is invalid pointer -> segfault Now object_find_create creates array of matching object handlers and object_find_next uses that array together with check for name. This prevents situation where between steps 2 and 3 new object is created with different name but sadly with same handler. Version-Release number of selected component (if applicable): Corosync master How reproducible: Often but it's race so depends on HW, ... Problem 1 is visible in valgrind. Steps to Reproduce: One node. # for i in `seq 1 5`;do (while true;do corosync-objctl -a | grep closed;done)& done # corosync -f Actual results: segfault Expected results: no segfault Additional info: