From: Thomas Veerman <thomas@minix3.org>
Date: Fri, 15 Jul 2011 14:11:34 +0000 (+0000)
Subject: Don't panic if owner has vanished before reply
X-Git-Tag: v3.2.0~457
X-Git-Url: http://zhaoyanbai.com/repos/%22/xml/v3/mem/static/tz-link.htm?a=commitdiff_plain;h=902e0e27e0802c722957153ba3dda0b79b9ec94f;p=minix.git

Don't panic if owner has vanished before reply
---

diff --git a/servers/vfs/select.c b/servers/vfs/select.c
index 705030785..6d84ff35e 100644
--- a/servers/vfs/select.c
+++ b/servers/vfs/select.c
@@ -777,18 +777,18 @@ int status;
 	return;
   }
 
-  /* The filp must be busy waiting for a reply. */
-  assert(f->filp_select_flags & FSF_BUSY);
-  assert(f->filp_count >= 1); /* There should be at least one owner */
-
-  /* Find vnode and check we got a reply from the device we expected */
-  vp = f->filp_vno;
-  assert(vp != NULL);
-  assert((vp->v_mode & I_TYPE) == I_CHAR_SPECIAL); /* Must be char. special */
-  if (vp->v_sdev != dev) {
-	printf("VFS (%s:%d): expected reply from dev %d not %d\n",
-		vp->v_sdev, dev);
-	return;
+  /* Is the filp still in use and busy waiting for a reply? The owner might
+   * have vanished before the driver was able to reply. */
+  if (f->filp_count >= 1 && (f->filp_select_flags & FSF_BUSY)) {
+	/* Find vnode and check we got a reply from the device we expected */
+	vp = f->filp_vno;
+	assert(vp != NULL);
+	assert((vp->v_mode & I_TYPE) == I_CHAR_SPECIAL); /* Must be char. special */
+	if (vp->v_sdev != dev) {
+		printf("VFS (%s:%d): expected reply from dev %d not %d\n",
+			vp->v_sdev, dev);
+		return;
+	}
   }
 
   /* No longer waiting for a reply from this device */