MFp4:

Fix reference counting bug, when device unreferenced before then
invalidated. To do it, do not handle validity flag as another
reference, but explicitly modify reference count each time flag is
modified.

Discovered by:	thompsa

4 files changed, 50 insertions, 30 deletions

diff --git a/sys/cam/ata/ata_xpt.c b/sys/cam/ata/ata_xpt.c
index 9e781cd..065f3ee 100644
--- a/sys/cam/ata/ata_xpt.c
+++ b/sys/cam/ata/ata_xpt.c
@@ -733,6 +733,7 @@ noerror:
 	case PROBE_SET_MULTI:
 		if (periph->path->device->flags & CAM_DEV_UNCONFIGURED) {
 			path->device->flags &= ~CAM_DEV_UNCONFIGURED;
+			xpt_acquire_device(path->device);
 			done_ccb->ccb_h.func_code = XPT_GDEV_TYPE;
 			xpt_action(done_ccb);
 			xpt_async(AC_FOUND_DEVICE, done_ccb->ccb_h.path,
@@ -777,6 +778,7 @@ noerror:
 		ata_device_transport(path);
 		if (periph->path->device->flags & CAM_DEV_UNCONFIGURED) {
 			path->device->flags &= ~CAM_DEV_UNCONFIGURED;
+			xpt_acquire_device(path->device);
 			done_ccb->ccb_h.func_code = XPT_GDEV_TYPE;
 			xpt_action(done_ccb);
 			xpt_async(AC_FOUND_DEVICE, done_ccb->ccb_h.path, done_ccb);
@@ -810,6 +812,7 @@ noerror:
 		path->device->flags |= CAM_DEV_IDENTIFY_DATA_VALID;
 		if (periph->path->device->flags & CAM_DEV_UNCONFIGURED) {
 			path->device->flags &= ~CAM_DEV_UNCONFIGURED;
+			xpt_acquire_device(path->device);
 			done_ccb->ccb_h.func_code = XPT_GDEV_TYPE;
 			xpt_action(done_ccb);
 			xpt_async(AC_FOUND_DEVICE, done_ccb->ccb_h.path,
@@ -1485,8 +1488,10 @@ ata_dev_async(u_int32_t async_code, struct cam_eb *bus, struct cam_et *target,
 				     CAM_EXPECT_INQ_CHANGE, NULL);
 		}
 		xpt_release_path(&newpath);
-	} else if (async_code == AC_LOST_DEVICE) {
+	} else if (async_code == AC_LOST_DEVICE &&
+	    (device->flags & CAM_DEV_UNCONFIGURED) == 0) {
 		device->flags |= CAM_DEV_UNCONFIGURED;
+		xpt_release_device(device);
 	} else if (async_code == AC_TRANSFER_NEG) {
 		struct ccb_trans_settings *settings;
 
diff --git a/sys/cam/cam_xpt.c b/sys/cam/cam_xpt.c
index 187683e..700363a 100644
--- a/sys/cam/cam_xpt.c
+++ b/sys/cam/cam_xpt.c
@@ -217,9 +217,7 @@ static void	 xpt_release_devq_device(struct cam_ed *dev, u_int count,
 					 int run_queue);
 static struct cam_et*
 		 xpt_alloc_target(struct cam_eb *bus, target_id_t target_id);
-static void	 xpt_release_target(struct cam_eb *bus, struct cam_et *target);
-static void	 xpt_release_device(struct cam_eb *bus, struct cam_et *target,
-				    struct cam_ed *device);
+static void	 xpt_release_target(struct cam_et *target);
 static struct cam_eb*
 		 xpt_find_bus(path_id_t path_id);
 static struct cam_et*
@@ -3521,9 +3519,9 @@ xpt_compile_path(struct cam_path *new_path, struct cam_periph *perph,
 		CAM_DEBUG(new_path, CAM_DEBUG_TRACE, ("xpt_compile_path\n"));
 	} else {
 		if (device != NULL)
-			xpt_release_device(bus, target, device);
+			xpt_release_device(device);
 		if (target != NULL)
-			xpt_release_target(bus, target);
+			xpt_release_target(target);
 		if (bus != NULL)
 			xpt_release_bus(bus);
 	}
@@ -3535,11 +3533,11 @@ xpt_release_path(struct cam_path *path)
 {
 	CAM_DEBUG(path, CAM_DEBUG_TRACE, ("xpt_release_path\n"));
 	if (path->device != NULL) {
-		xpt_release_device(path->bus, path->target, path->device);
+		xpt_release_device(path->device);
 		path->device = NULL;
 	}
 	if (path->target != NULL) {
-		xpt_release_target(path->bus, path->target);
+		xpt_release_target(path->target);
 		path->target = NULL;
 	}
 	if (path->bus != NULL) {
@@ -4375,15 +4373,15 @@ xpt_alloc_target(struct cam_eb *bus, target_id_t target_id)
 }
 
 static void
-xpt_release_target(struct cam_eb *bus, struct cam_et *target)
+xpt_release_target(struct cam_et *target)
 {
 
 	if ((--target->refcount == 0)
 	 && (TAILQ_FIRST(&target->ed_entries) == NULL)) {
-		TAILQ_REMOVE(&bus->et_entries, target, links);
-		bus->generation++;
+		TAILQ_REMOVE(&target->bus->et_entries, target, links);
+		target->bus->generation++;
+		xpt_release_bus(target->bus);
 		free(target, M_CAMXPT);
-		xpt_release_bus(bus);
 	}
 }
 
@@ -4470,13 +4468,18 @@ xpt_alloc_device(struct cam_eb *bus, struct cam_et *target, lun_id_t lun_id)
 	return (device);
 }
 
-static void
-xpt_release_device(struct cam_eb *bus, struct cam_et *target,
-		   struct cam_ed *device)
+void
+xpt_acquire_device(struct cam_ed *device)
+{
+
+	device->refcount++;
+}
+
+void
+xpt_release_device(struct cam_ed *device)
 {
 
-	if ((--device->refcount == 0)
-	 && ((device->flags & CAM_DEV_UNCONFIGURED) != 0)) {
+	if (--device->refcount == 0) {
 		struct cam_devq *devq;
 
 		if (device->alloc_ccb_entry.pinfo.index != CAM_UNQUEUED_INDEX
@@ -4486,16 +4489,16 @@ xpt_release_device(struct cam_eb *bus, struct cam_et *target,
 		if ((device->flags & CAM_DEV_REL_TIMEOUT_PENDING) != 0)
 				callout_stop(&device->callout);
 
-		TAILQ_REMOVE(&target->ed_entries, device,links);
-		target->generation++;
-		bus->sim->max_ccbs -= device->ccbq.devq_openings;
+		TAILQ_REMOVE(&device->target->ed_entries, device,links);
+		device->target->generation++;
+		device->target->bus->sim->max_ccbs -= device->ccbq.devq_openings;
 		/* Release our slot in the devq */
-		devq = bus->sim->devq;
+		devq = device->target->bus->sim->devq;
 		cam_devq_resize(devq, devq->alloc_queue.array_size - 1);
 		camq_fini(&device->drvq);
 		cam_ccbq_fini(&device->ccbq);
+		xpt_release_target(device->target);
 		free(device, M_CAMXPT);
-		xpt_release_target(bus, target);
 	}
 }
 
diff --git a/sys/cam/cam_xpt_internal.h b/sys/cam/cam_xpt_internal.h
index 9e5e3f1..643ddf1 100644
--- a/sys/cam/cam_xpt_internal.h
+++ b/sys/cam/cam_xpt_internal.h
@@ -37,9 +37,7 @@ struct cam_ed;
 typedef struct cam_ed * (*xpt_alloc_device_func)(struct cam_eb *bus,
 					         struct cam_et *target,
 					         lun_id_t lun_id);
-typedef void (*xpt_release_device_func)(struct cam_eb *bus,
-				        struct cam_et *target,
-				        struct cam_ed *device);
+typedef void (*xpt_release_device_func)(struct cam_ed *device);
 typedef void (*xpt_action_func)(union ccb *start_ccb);
 typedef void (*xpt_dev_async_func)(u_int32_t async_code,
 				   struct cam_eb *bus,
@@ -172,6 +170,8 @@ struct xpt_xport *	ata_get_xport(void);
 struct cam_ed *		xpt_alloc_device(struct cam_eb *bus,
 					 struct cam_et *target,
 					 lun_id_t lun_id);
+void			xpt_acquire_device(struct cam_ed *device);
+void			xpt_release_device(struct cam_ed *device);
 void			xpt_run_dev_sendq(struct cam_eb *bus);
 int			xpt_schedule_dev(struct camq *queue, cam_pinfo *dev_pinfo,
 					 u_int32_t new_priority);
diff --git a/sys/cam/scsi/scsi_xpt.c b/sys/cam/scsi/scsi_xpt.c
index a240db8..d780f9a 100644
--- a/sys/cam/scsi/scsi_xpt.c
+++ b/sys/cam/scsi/scsi_xpt.c
@@ -1076,8 +1076,10 @@ probedone(struct cam_periph *periph, union ccb *done_ccb)
 				else
 					PROBE_SET_ACTION(softc, PROBE_SERIAL_NUM_0);
 
-				path->device->flags &= ~CAM_DEV_UNCONFIGURED;
-
+				if (path->device->flags & CAM_DEV_UNCONFIGURED) {
+					path->device->flags &= ~CAM_DEV_UNCONFIGURED;
+					xpt_acquire_device(path->device);
+				}
 				xpt_release_ccb(done_ccb);
 				xpt_schedule(periph, priority);
 				return;
@@ -1336,8 +1338,12 @@ probedone(struct cam_periph *periph, union ccb *done_ccb)
 			CAM_DEBUG(periph->path, CAM_DEBUG_INFO,
 			    ("Leave Domain Validation\n"));
 		}
+		if (path->device->flags & CAM_DEV_UNCONFIGURED) {
+			path->device->flags &= ~CAM_DEV_UNCONFIGURED;
+			xpt_acquire_device(path->device);
+		}
 		path->device->flags &=
-		    ~(CAM_DEV_UNCONFIGURED|CAM_DEV_IN_DV|CAM_DEV_DV_HIT_BOTTOM);
+		    ~(CAM_DEV_IN_DV|CAM_DEV_DV_HIT_BOTTOM);
 		if ((softc->flags & PROBE_NO_ANNOUNCE) == 0) {
 			/* Inform the XPT that a new device has been found */
 			done_ccb->ccb_h.func_code = XPT_GDEV_TYPE;
@@ -1387,8 +1393,12 @@ probedone(struct cam_periph *periph, union ccb *done_ccb)
 			CAM_DEBUG(periph->path, CAM_DEBUG_INFO,
 			    ("Leave Domain Validation Successfully\n"));
 		}
+		if (path->device->flags & CAM_DEV_UNCONFIGURED) {
+			path->device->flags &= ~CAM_DEV_UNCONFIGURED;
+			xpt_acquire_device(path->device);
+		}
 		path->device->flags &=
-		    ~(CAM_DEV_UNCONFIGURED|CAM_DEV_IN_DV|CAM_DEV_DV_HIT_BOTTOM);
+		    ~(CAM_DEV_IN_DV|CAM_DEV_DV_HIT_BOTTOM);
 		if ((softc->flags & PROBE_NO_ANNOUNCE) == 0) {
 			/* Inform the XPT that a new device has been found */
 			done_ccb->ccb_h.func_code = XPT_GDEV_TYPE;
@@ -2375,8 +2385,10 @@ scsi_dev_async(u_int32_t async_code, struct cam_eb *bus, struct cam_et *target,
 				     CAM_EXPECT_INQ_CHANGE, NULL);
 		}
 		xpt_release_path(&newpath);
-	} else if (async_code == AC_LOST_DEVICE) {
+	} else if (async_code == AC_LOST_DEVICE &&
+	    (device->flags & CAM_DEV_UNCONFIGURED) == 0) {
 		device->flags |= CAM_DEV_UNCONFIGURED;
+		xpt_release_device(device);
 	} else if (async_code == AC_TRANSFER_NEG) {
 		struct ccb_trans_settings *settings;