From 45617b727e280cac384a28ae3d96145e066e6197 Mon Sep 17 00:00:00 2001
From: Reid Wahl <nrwahl@protonmail.com>
Date: Fri, 3 Feb 2023 12:08:57 -0800
Subject: [PATCH] Fix: fencer: Prevent double g_source_remove of op_timer_one

QE observed a rarely reproducible core dump in the fencer during
Pacemaker shutdown, in which we try to g_source_remove() an op timer
that's already been removed.

free_stonith_remote_op_list()
-> g_hash_table_destroy()
-> g_hash_table_remove_all_nodes()
-> clear_remote_op_timers()
-> g_source_remove()
-> crm_glib_handler()
-> "Source ID 190 was not found when attempting to remove it"

The likely cause is that request_peer_fencing() doesn't set
op->op_timer_one to 0 after calling g_source_remove() on it, so if that
op is still in the stonith_remote_op_list at shutdown with the same
timer, clear_remote_op_timers() tries to remove the source for
op_timer_one again.

There are only five locations that call g_source_remove() on a
remote_fencing_op_t timer.
* Three of them are in clear_remote_op_timers(), which first 0-checks
  the timer and then sets it to 0 after g_source_remove().
* One is in remote_op_query_timeout(), which does the same.
* The last is the one we fix here in request_peer_fencing().

I don't know all the conditions of QE's test scenario at this point.
What I do know:
* have-watchdog=true
* stonith-watchdog-timeout=10
* no explicit topology
* fence agent script is missing for the configured fence device
* requested fencing of one node
* cluster shutdown

Fixes RHBZ2166967

Signed-off-by: Reid Wahl <nrwahl@protonmail.com>
---
 daemons/fenced/fenced_remote.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/daemons/fenced/fenced_remote.c b/daemons/fenced/fenced_remote.c
index d61b5bd..b7426ff 100644
--- a/daemons/fenced/fenced_remote.c
+++ b/daemons/fenced/fenced_remote.c
@@ -1825,6 +1825,7 @@ request_peer_fencing(remote_fencing_op_t *op, peer_device_info_t *peer)
         op->state = st_exec;
         if (op->op_timer_one) {
             g_source_remove(op->op_timer_one);
+            op->op_timer_one = 0;
         }
 
         if (!((stonith_watchdog_timeout_ms > 0)
-- 
2.31.1