File 0002-autofs-5.1.9-fix-deadlock-in-remount.patch of Package autofs

From 7189daddda95fef293a32207ad2d86b0158b6f68 Mon Sep 17 00:00:00 2001
From: Ian Kent <raven@themaw.net>
Date: Tue, 5 Dec 2023 13:25:49 +0800
Subject: [PATCH 02/14] autofs-5.1.9 - fix deadlock in remount

If we're starting up or trying to re-connect to an existing direct mount
we could be iterating through the map entries with the cache readlock
held so we can't just take the writelock for direct mounts. But when
trying to re-connect to an existing mount at startup there won't be any
other process updating the map entry cache.

Signed-off-by: Ian Kent <raven@themaw.net>
(cherry picked from commit ad518262e9294ad465120cdb6fd29fdd4ccb179d)
---
 CHANGELOG           |  1 +
 modules/parse_sun.c | 26 ++++++++++++++++++++++++--
 2 files changed, 25 insertions(+), 2 deletions(-)

Index: autofs-5.1.9/CHANGELOG
===================================================================
--- autofs-5.1.9.orig/CHANGELOG
+++ autofs-5.1.9/CHANGELOG
@@ -2,6 +2,7 @@
 =======
 - Fix incompatible function pointer types in cyrus-sasl module.
 - fix get parent multi-mount check in try_remount().
+- fix deadlock in remount.
 
 02/11/2023 autofs-5.1.9
 - fix kernel mount status notification.
Index: autofs-5.1.9/modules/parse_sun.c
===================================================================
--- autofs-5.1.9.orig/modules/parse_sun.c
+++ autofs-5.1.9/modules/parse_sun.c
@@ -889,7 +889,18 @@ update_offset_entry(struct autofs_point
 			strcpy(m_mapent, loc);
 	}
 
-	cache_writelock(mc);
+	/*
+	 * If we're starting up or trying to re-connect to an existing
+	 * direct mount we could be iterating through the map entries
+	 * with the readlock held so we can't just take the writelock
+	 * for direct mounts. But at when trying to re-connect to an
+	 * existing mount at startup there won't be any other process
+	 * updating the map entry cache.
+	 */
+	if (ap->state == ST_INIT && ap->flags & MOUNT_FLAG_REMOUNT)
+		cache_readlock(mc);
+	else
+		cache_writelock(mc);
 	ret = cache_update_offset(mc, name, m_key, m_mapent, age);
 
 	me = cache_lookup_distinct(mc, m_key);
@@ -1582,7 +1593,18 @@ dont_expand:
 			free(myoptions);
 		} while (*p == '/' || (*p == '"' && *(p + 1) == '/'));
 
-		cache_writelock(mc);
+		/*
+		 * If we're starting up or trying to re-connect to an existing
+		 * direct mount we could be iterating through the map entries
+		 * with the readlock held so we can't just take the writelock
+		 * for direct mounts. But at when trying to re-connect to an
+		 * existing mount at startup there won't be any other process
+		 * updating the map entry cache.
+		 */
+		if (ap->state == ST_INIT && ap->flags & MOUNT_FLAG_REMOUNT)
+			cache_readlock(mc);
+		else
+			cache_writelock(mc);
 		me = cache_lookup_distinct(mc, name);
 		if (!me) {
 			cache_unlock(mc);