svn commit: r294957 - head/sys/dev/filemon

[Bryan Drewery]

Author: bdrewery
Date: Wed Jan 27 21:37:43 2016
New Revision: 294957
URL: https://svnweb.freebsd.org/changeset/base/294957

Log:
  filemon_dtr: Lock the associated filemon handle before writing to it.
  
  Reported by:	mjg
  MFC after:	2 weeks
  Sponsored by:	EMC / Isilon Storage Division

Modified:
  head/sys/dev/filemon/filemon.c

Modified: head/sys/dev/filemon/filemon.c
==============================================================================
--- head/sys/dev/filemon/filemon.c	Wed Jan 27 21:27:05 2016	(r294956)
+++ head/sys/dev/filemon/filemon.c	Wed Jan 27 21:37:43 2016	(r294957)
@@ -126,14 +126,16 @@ filemon_dtr(void *data)
 	struct filemon *filemon = data;
 
 	if (filemon != NULL) {
-		struct file *fp = filemon->fp;
+		struct file *fp;
 
-		/* Get exclusive write access. */
+		/* Follow same locking order as filemon_pid_check. */
 		filemon_lock_write();
+		filemon_filemon_lock(filemon);
 
 		/* Remove from the in-use list. */
 		TAILQ_REMOVE(&filemons_inuse, filemon, link);
 
+		fp = filemon->fp;
 		filemon->fp = NULL;
 		filemon->pid = -1;
 
@@ -141,6 +143,7 @@ filemon_dtr(void *data)
 		TAILQ_INSERT_TAIL(&filemons_free, filemon, link);
 
 		/* Give up write access. */
+		filemon_filemon_unlock(filemon);
 		filemon_unlock_write();
 
 		if (fp != NULL)