diff -ru cronie-1.4.11/src/database.c cronie-1.4.11_patched/src/database.c

--- cronie-1.4.11/src/database.c	2018-10-19 15:29:55.630225195 +0200

+++ cronie-1.4.11_patched/src/database.c	2018-10-19 15:32:14.552093860 +0200

@@ -48,6 +48,7 @@

 #include "pathnames.h"

 #define TMAX(a,b) ((a)>(b)?(a):(b))

+#define TMIN(a,b) ((a)<(b)?(a):(b))

 /* size of the event structure, not counting name */

 #define EVENT_SIZE  (sizeof (struct inotify_event))

@@ -237,6 +238,8 @@

 	if ((crontab_fd = check_open(tabname, uname, pw, &mtime)) == -1)

 		goto next_crontab;

+	mtime = TMIN(new_db->mtime, mtime);

+

 	Debug(DLOAD, ("\t%s:", fname));

 	if (old_db != NULL)

@@ -261,7 +264,7 @@

 		 * we finish with the crontab...

 		 */

 		Debug(DLOAD, (" [delete old data]"));

-			unlink_user(old_db, u);

+		unlink_user(old_db, u);

 		free_user(u);

 		log_it(fname, getpid(), "RELOAD", tabname, 0);

 	}

@@ -328,18 +331,18 @@

 	cron_db new_db;

 	DIR_T *dp;

 	DIR *dir;

-	struct timeval time;

+	struct timeval timev;

 	fd_set rfds;

 	int retval;

 	char buf[BUF_LEN];

 	pid_t pid = getpid();

-	time.tv_sec = 0;

-	time.tv_usec = 0;

+	timev.tv_sec = 0;

+	timev.tv_usec = 0;

 	FD_ZERO(&rfds);

 	FD_SET(old_db->ifd, &rfds);

-	retval = select(old_db->ifd + 1, &rfds, NULL, NULL, &time);

+	retval = select(old_db->ifd + 1, &rfds, NULL, NULL, &timev;;

 	if (retval == -1) {

 		if (errno != EINTR)

 			log_it("CRON", pid, "INOTIFY", "select failed", errno);

@@ -348,6 +351,7 @@

 	else if (FD_ISSET(old_db->ifd, &rfds)) {

 		new_db.head = new_db.tail = NULL;

 		new_db.ifd = old_db->ifd;

+		new_db.mtime = time(NULL) - 1;

 		while ((retval = read(old_db->ifd, buf, sizeof (buf))) == -1 &&

 			errno == EINTR) ;

@@ -452,14 +456,17 @@

 	DIR *dir;

 	pid_t pid = getpid();

 	int is_local = 0;

+	time_t now;

 	Debug(DLOAD, ("[%ld] load_database()\n", (long) pid));

-		/* before we start loading any data, do a stat on SPOOL_DIR

-		 * so that if anything changes as of this moment (i.e., before we've

-		 * cached any of the database), we'll see the changes next time.

-		 */

-		if (stat(SPOOL_DIR, &statbuf) < OK) {

+	now = time(NULL);

+

+	/* before we start loading any data, do a stat on SPOOL_DIR

+	 * so that if anything changes as of this moment (i.e., before we've

+	 * cached any of the database), we'll see the changes next time.

+	 */

+	if (stat(SPOOL_DIR, &statbuf) < OK) {

 		log_it("CRON", pid, "STAT FAILED", SPOOL_DIR, errno);

 		statbuf.st_mtime = 0;

 	}

@@ -492,13 +499,17 @@

 	 * Note that old_db->mtime is initialized to 0 in main(), and

 	 * so is guaranteed to be different than the stat() mtime the first

 	 * time this function is called.

+	 *

+	 * We also use now - 1 as the upper bound of timestamp to avoid race,

+	 * when a crontab is updated twice in a single second when we are

+         * just reading it.

 	 */

-	if (old_db->mtime == TMAX(crond_stat.st_mtime,

-			TMAX(statbuf.st_mtime, syscron_stat.st_mtime))

+	if (old_db->mtime == TMIN(now - 1, TMAX(crond_stat.st_mtime,

+			TMAX(statbuf.st_mtime, syscron_stat.st_mtime)))

 		) {

 		Debug(DLOAD, ("[%ld] spool dir mtime unch, no load needed.\n",

 				(long) pid));

-			return 0;

+		return 0;

 	}

 	/* something's different.  make a new database, moving unchanged

@@ -506,8 +517,7 @@

 	 * actually changed.  Whatever is left in the old database when

 	 * we're done is chaff -- crontabs that disappeared.

 	 */

-	new_db.mtime = TMAX(crond_stat.st_mtime,

-		TMAX(statbuf.st_mtime, syscron_stat.st_mtime));

+	new_db.mtime = now - 1;

 	new_db.head = new_db.tail = NULL;

 #if defined WITH_INOTIFY

 	new_db.ifd = old_db->ifd;