From acbebb1ac5f966b6e3fbb9d11fde95408b4bdf52 Mon Sep 17 00:00:00 2001
From: Morris Jette <jette@schedmd.com>
Date: Mon, 9 Jan 2012 11:33:07 -0800
Subject: [PATCH] Explain use of fork() without exec()
---
src/slurmd/slurmd/req.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/src/slurmd/slurmd/req.c b/src/slurmd/slurmd/req.c
index f312f882487..add5e0374b0 100644
--- a/src/slurmd/slurmd/req.c
+++ b/src/slurmd/slurmd/req.c
@@ -2474,7 +2474,16 @@ _rpc_file_bcast(slurm_msg_t *msg)
/* The child actually performs the I/O and exits with
* a return code, do not return! */
- /* set the child's group list */
+ /*********************************************************************\
+ * NOTE: It would be best to do an exec() immediately after the fork()
+ * in order to help prevent a possible deadlock in the child process
+ * due to locks being set at the time of the fork and being freed by
+ * the parent process, but not freed by the child process. Performing
+ * the work inline is done for simplicity. Note that the logging
+ * performed by error() should be safe due to the use of
+ * atfork_install_handlers() as defined in src/common/log.c.
+ * Change the code below with caution.
+ \*********************************************************************/
if (setgroups(ngroups, groups) < 0) {
error("sbcast: uid: %u setgroups: %s", req_uid,
strerror(errno));
--
GitLab