From f98c5f53d4661ec22097d36f5debd195491ec3c6 Mon Sep 17 00:00:00 2001
From: Karel Zak <kzak@redhat.com>
Date: Thu, 15 Dec 2016 14:40:26 +0100
Subject: [PATCH 101/116] more: avoid double free() on exit
On 'q' command more(1) calls end_it() function with _exit(). The
_exit() may suspend program execution due to pending I/O on very
loaded server. In this time SIGINT may be delivered due to impatient
user who will press ^C.
And then end_it() cleanup function may be executed by signal handler
too. The result is double free()...
Upstream: https://github.com/karelzak/util-linux/commit/0ed2a954714992938b35893b70197090a61b3b2e
Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=1403971
Signed-off-by: Karel Zak <kzak@redhat.com>
---
text-utils/more.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/text-utils/more.c b/text-utils/more.c
index 0e9c2bd..f98cb14 100644
--- a/text-utils/more.c
+++ b/text-utils/more.c
@@ -763,6 +763,14 @@ void chgwinsz(int dummy __attribute__((__unused__)))
/* Clean up terminal state and exit. Also come here if interrupt signal received */
void __attribute__((__noreturn__)) end_it(int dummy __attribute__((__unused__)))
{
+ /* May be executed as a signal handler as well as by main process.
+ *
+ * The _exit() may wait for pending I/O for really long time, be sure
+ * that signal handler is not executed in this time to avoid double
+ * de-initialization (free() calls, etc.).
+ */
+ signal(SIGINT, SIG_IGN);
+
reset_tty();
if (clreol) {
putchar('\r');
--
2.9.3