** Description changed:
Binary package hint: multipath-tools
+
+ ==========================================
+ SRU Justification:
+ 1. Impact: segv on multipathd shutdown
+ 2. How bug was addressed: a patch was cherrypicked from upstream which fixes
this
+ 3. Minimal patch: see patch in attached bzr tree
+ 4. TEST CASE: stop multipathd.
+ 5. Regression potential: none, this patch was taken from upstream.
+ ==========================================
I received a coredump from a customer (running a lucid-based system).
Analyzing the core from multipathd shows that we are crashing in
waiter.c::free_waiter().
void free_waiter (void *data)
{
- struct event_thread *wp = (struct event_thread *)data;
+ struct event_thread *wp = (struct event_thread *)data;
- /*
- * indicate in mpp that the wp is already freed storage
- */
- lock(wp->vecs->lock);
+ /*
+ * indicate in mpp that the wp is already freed storage
+ */
+ lock(wp->vecs->lock);
- if (wp->mpp)
- /*
- * be careful, mpp may already be freed -- null if so
- */
- wp->mpp->waiter = NULL;
- else
- condlog(3, "free_waiter, mpp freed before wp=%p,", wp);
+ if (wp->mpp)
+ /*
+ * be careful, mpp may already be freed -- null if so
+ */
+ wp->mpp->waiter = NULL;
+ else
+ condlog(3, "free_waiter, mpp freed before wp=%p,", wp);
- unlock(wp->vecs->lock); <<< Crashing here
+ unlock(wp->vecs->lock); <<< Crashing here
- if (wp->dmt)
- dm_task_destroy(wp->dmt);
+ if (wp->dmt)
+ dm_task_destroy(wp->dmt);
- FREE(wp);
+ FREE(wp);
}
The lock is NULL:
(gdb) print wp->vecs->lock
$3 = (pthread_mutex_t *) 0x0
This appears to be the upstream issue fixed here:
http://git.kernel.org/gitweb.cgi?p=linux/storage/multipath-tools/.git;a=commitdiff;h=a403f57b991f3be7c7ea6250d95fad1554c9d6ca
This fix is currently missing from all versions of multipath-tools in
lucid->natty.
(The original customer issue was filed in the private bug #712875.)
** Also affects: multipath-tools (Ubuntu Lucid)
Importance: Undecided
Status: New
** Also affects: multipath-tools (Ubuntu Maverick)
Importance: Undecided
Status: New
--
You received this bug notification because you are a member of Ubuntu
Server Team, which is subscribed to multipath-tools in Ubuntu.
https://bugs.launchpad.net/bugs/713237
Title:
shutdown segv due to race w/ free_waiter threads
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