From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Thu, 5 Mar 2020 21:52:32 +0000 (-0500)
Subject: Fix: sessiond: occasional badfd error on repeated SIGTERM
X-Git-Tag: v2.13.0-rc1~720
X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=11f8d2f7f00b61b467bf78518036d7cb96e8b9fc

Fix: sessiond: occasional badfd error on repeated SIGTERM

The session daemon occasionally prints the following messages
when it received multiple SIGTERM signals:

PERROR - 16:50:18.505585257 [49845/49845]: write poll pipe: Bad file
descriptor (in notify_thread_pipe() at utils.c:35)

This is caused by a (somewhat inevitable) race between the teardown of
the daemon and the closing of its quit pipe. This happens more often
when kernel modules take a long time to be unloaded and the user
spams ctrl+c in the hope of convincing the daemon process to close
faster since modules are unloaded after closing the quit pipe.

Setting closed pipe fds to '-1' is safe anyway and is already
handled by the notify_thread_pipe() util.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: If08a455c65055dcb56ffbad3703173e6a45cfba5
---

diff --git a/src/common/utils.c b/src/common/utils.c
index d9bacad0e..646ebbbc7 100644
--- a/src/common/utils.c
+++ b/src/common/utils.c
@@ -537,6 +537,7 @@ void utils_close_pipe(int *src)
 		if (ret) {
 			PERROR("close pipe");
 		}
+		src[i] = -1;
 	}
 }