From 15e40a45a990d2a6d786ef2282b9eb56b20a9231 Mon Sep 17 00:00:00 2001
From: "Rob Swindell (on macOS)" <rob@synchro.net>
Date: Sat, 23 Nov 2024 16:02:54 -0800
Subject: [PATCH] Fix potential deadlock in getnodedat(), observed on macOS
Upon any node.dab lock or read failure, this code would cause errormsg() which
would often/usually end up claling getnodedat() which would block forever trying
to acquire the ndoefile_mutex (introduced in commit b9633069, I'm not clear why).
Unlock/release the mutex *before* calling errormsg().
---
src/sbbs3/getnode.cpp | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/sbbs3/getnode.cpp b/src/sbbs3/getnode.cpp
index 0864752568..cb789b8101 100644
--- a/src/sbbs3/getnode.cpp
+++ b/src/sbbs3/getnode.cpp
@@ -47,8 +47,8 @@ int sbbs_t::getnodedat(uint number, node_t *node, bool lockit)
pthread_mutex_lock(&nodefile_mutex);
if(nodefile==-1) {
if((nodefile=nopen(str,O_RDWR|O_DENYNONE))==-1) {
- errormsg(WHERE,ERR_OPEN,str,O_RDWR|O_DENYNONE);
pthread_mutex_unlock(&nodefile_mutex);
+ errormsg(WHERE,ERR_OPEN,str,O_RDWR|O_DENYNONE);
return(errno);
}
}
@@ -77,11 +77,11 @@ int sbbs_t::getnodedat(uint number, node_t *node, bool lockit)
}
if(count==LOOP_NODEDAB) {
- errormsg(WHERE,rd==sizeof(node_t) ? ERR_LOCK : ERR_READ,"node.dab",number+1);
if(nodefile!=-1)
close(nodefile);
nodefile=-1;
pthread_mutex_unlock(&nodefile_mutex);
+ errormsg(WHERE,rd==sizeof(node_t) ? ERR_LOCK : ERR_READ,"node.dab",number+1);
return(-2);
}
pthread_mutex_unlock(&nodefile_mutex);
--
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