Red Hat Bugzilla – Bug 1247851
Glusterfsd crashes because of thread-unsafe code in gf_authenticate
Last modified: 2018-01-30 02:57:39 EST
+++ This bug was initially created as a clone of Bug #1247765 +++
This caused a failure on a regression test for an unrelated patch.
The relevant part of the stack trace looks like this.
#2 0x00007f3f84194d18 in dict_get (this=0x7f3f680023ec
#3 0x00007f3f744a4a45 in gf_auth (input_params=0x7f3f680023ec
#4 0x00007f3f748d9894 in map (this=0x7f3f70031dec
#5 0x00007f3f84196885 in dict_foreach_match (dict=0x7f3f70031dec
#6 0x00007f3f8419675d in dict_foreach (dict=0x7f3f70031dec
#7 0x00007f3f748d99d5 in gf_authenticate
In frame 2, "this" looks like a valid pointer, but the structure it points to seems to contain garbage. The problem becomes evident when we look at frame 7.
(gdb) p input_params
$3 = (dict_t *) 0x7f3f700665ac
(gdb) p __input_params
$4 = (dict_t *) 0x7f3f680023ec
So the value we're using is from the global __input_params. This should match the parameter input_params (which looks OK) but that's not the case. Apparently some other thread came in and stomped the unprotected global variable while we were still using it. This concurrency issue was actually reported - and fixed! - on September 13, 2013.
Unfortunately, since most people weren't running multiple network threads, they never saw the problem, didn't take it seriously, and bikeshedded the patch to death. Now that we have multi-threaded epoll, it's going to keep biting everyone until it's fixed.
--- Additional comment from Anand Avati on 2015-07-28 16:27:49 EDT ---
REVIEW: http://review.gluster.org/11780 (rpc: fix concurrency bug in gf_authenticate) posted (#1) for review on master by Jeff Darcy (firstname.lastname@example.org)
As part of rebases, this patch is already in RHGS releases 3.2 +