From: Valentine Krasnobaeva <vkrasnobaeva@haproxy.com>
Date: Fri, 4 Oct 2024 08:59:06 +0000 (+0200)
Subject: MINOR: mworker: mworker_catch_sigchld: use fd_delete instead of close
X-Git-Tag: v3.1-dev10~30
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=9b27f82da3cc406dd3935cb106802c2fa4f5ba9e;p=thirdparty%2Fhaproxy.git

MINOR: mworker: mworker_catch_sigchld: use fd_delete instead of close

If the worker exits due to failure or due to receiving TERM signal, in the
master context, we can't now simply close the master's fd (ipc_fd[0]) of
the inherited master CLI sockpair.

When the worker is created, in the master process context MASTER proxy listener
is bound to ipc_fd[0]. When this worker fails or exits, master process is
always in its polling loop. So, closing some fd in its context immediately
triggers the BUG_ON(fd->owner), as the poller try to reinsert the "freed" fd
into fdtab and try to reuse it. We must call fd_delete in this case. This will
deinitializes fd auxilary data and closes its properly.
---

diff --git a/src/mworker.c b/src/mworker.c
index 967bf7cfae..53aaf4bdb5 100644
--- a/src/mworker.c
+++ b/src/mworker.c
@@ -365,7 +365,6 @@ restart_wait:
 				continue;
 
 			LIST_DELETE(&child->list);
-			close(child->ipc_fd[0]);
 			childfound = 1;
 			break;
 		}
@@ -377,6 +376,7 @@ restart_wait:
 			/* check if exited child is a current child */
 			if (!(child->options & PROC_O_LEAVING)) {
 				if (child->options & PROC_O_TYPE_WORKER) {
+					fd_delete(child->ipc_fd[0]);
 					if (status < 128)
 						ha_warning("Current worker (%d) exited with code %d (%s)\n", exitpid, status, "Exit");
 					else
@@ -399,6 +399,7 @@ restart_wait:
 				if (exitcode < 0 && status != 0 && status != 143)
 					exitcode = status;
 			} else {
+				fd_delete(child->ipc_fd[0]);
 				if (child->options & PROC_O_TYPE_WORKER) {
 					ha_warning("Former worker (%d) exited with code %d (%s)\n", exitpid, status, (status >= 128) ? strsignal(status - 128) : "Exit");
 					delete_oldpid(exitpid);