This patch fixes 2 logging bugs:
o multipath command prints unexpected log message like
"libdevmapper: libdm-common.c(303): Created /dev/mapper/<mapname>"
o multipathd doesn't log messages like "--------shut down------"
during the exit path
What is the problem:
o multipath command and multipathd register dm_write_log() using
dm_log_init() and it can be called from libdevmapper codes like
dm_lib_release().
o dm_write_log() references the global "conf" to find the verbosity,
but it is freed before dm_lib_release() calls dm_write_log().
o So dm_write_log() reads garbage value like big vervosity.
What does the patch do:
o multipath command sets NULL to "conf" after freeing it.
This prevents dm_write_log() from reading garbage data.
o multipath command and multipathd free "conf" after all logging
are completed, because the logging functions reference it
to find the verbosity.
Signed-off-by: Kiyoshi Ueda <k-ueda@xxxxxxxxxxxxx>
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
---
multipath/main.c | 10 +++++++++-
multipathd/main.c | 10 ++++++++--
2 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/multipath/main.c b/multipath/main.c
index 0f4b2d2..b6ea6fd 100644
--- a/multipath/main.c
+++ b/multipath/main.c
@@ -429,9 +429,17 @@ main (int argc, char *argv[])
out:
sysfs_cleanup();
- free_config(conf);
dm_lib_release();
dm_lib_exit();
+
+ /*
+ * Freeing config must be done after dm_lib_exit(), because
+ * the logging function (dm_write_log()), which is called there,
+ * references the config.
+ */
+ free_config(conf);
+ conf = NULL;
+
#ifdef _DEBUG_
dbg_free_final(NULL);
#endif
diff --git a/multipathd/main.c b/multipathd/main.c
index 50e7441..385521c 100644
--- a/multipathd/main.c
+++ b/multipathd/main.c
@@ -1373,8 +1373,6 @@ child (void * param)
vecs->lock = NULL;
FREE(vecs);
vecs = NULL;
- free_config(conf);
- conf = NULL;
condlog(2, "--------shut down-------");
@@ -1384,6 +1382,14 @@ child (void * param)
dm_lib_release();
dm_lib_exit();
+ /*
+ * Freeing config must be done after condlog() and dm_lib_exit(),
+ * because logging functions like dlog() and dm_write_log()
+ * reference the config.
+ */
+ free_config(conf);
+ conf = NULL;
+
#ifdef _DEBUG_
dbg_free_final(NULL);
#endif
--
1.5.2.4
--
dm-devel mailing list
dm-devel@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/dm-devel
