This bug has been copied from bug #673058 and has been proposed to be backported to 5.6 z-stream (EUS).
in kernel-2.6.18-238.9.1.el5 linux-2.6-md-dm-mpath-fix-null-deref-when-path-parameter-missing.patch linux-2.6-md-dm-mpath-wait-for-pg_init-completion-on-suspend.patch linux-2.6-md-dm-mpath-hold-io-until-all-pg_inits-completed.patch linux-2.6-md-dm-mpath-skip-activate_path-for-failed-paths.patch linux-2.6-md-dm-mpath-pass-struct-pgpath-to-pg-init-done.patch linux-2.6-md-dm-mpath-prevent-io-from-work-queue-while-suspended.patch linux-2.6-md-dm-mpath-add-mutex-to-sync-adding-and-flushing-work.patch linux-2.6-md-dm-mpath-flush-workqueues-before-suspend-completes.patch
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on therefore solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2011-0429.html
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: A race could occur when an internal multipath structure (pgpath) was freed before it was used to signal the path group initialization was complete (via pg_init_done). This update includes a number of fixes that address this issue. multipath is now increasingly robust when multipathd restarts are combined with I/O operations to multipath devices and storage failures.