Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

Pull SCSI fixes from James Bottomley:
 "This is three essential bug fixes for various SCSI parts.

  The only affected users are SCSI multi-path via device handler
  (basically all the enterprise) and mvsas users.  The dh bugs are an
  async entanglement in boot resulting in a serious WARN_ON trip and a
  use after free on remove leading to a crash with strict memory
  accounting.  The mvsas bug manifests as a null deref oops but only on
  abort sequences; however, these can commonly occur with SATA attached
  devices, hence the fix"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi_dh: don't try to load a device handler during async probing
  scsi_dh: fix use-after-free when removing scsi device
  mvsas: Fix NULL pointer dereference in mvs_slot_task_free

4 files changed, 12 insertions, 2 deletions

diff --git a/drivers/scsi/mvsas/mv_sas.c b/drivers/scsi/mvsas/mv_sas.c
index 454536c49315..9c780740fb82 100644
--- a/drivers/scsi/mvsas/mv_sas.c
+++ b/drivers/scsi/mvsas/mv_sas.c
@@ -887,6 +887,8 @@ static void mvs_slot_free(struct mvs_info *mvi, u32 rx_desc)
 static void mvs_slot_task_free(struct mvs_info *mvi, struct sas_task *task,
                           struct mvs_slot_info *slot, u32 slot_idx)
 {
+        if (!slot)
+                return;
         if (!slot->task)
                 return;
         if (!sas_protocol_ata(task->task_proto))
diff --git a/drivers/scsi/scsi_dh.c b/drivers/scsi/scsi_dh.c
index 0a2168e69bbc..e7649ed3f667 100644
--- a/drivers/scsi/scsi_dh.c
+++ b/drivers/scsi/scsi_dh.c
@@ -226,16 +226,20 @@ int scsi_dh_add_device(struct scsi_device *sdev)
 
         drv = scsi_dh_find_driver(sdev);
         if (drv)
-                devinfo = scsi_dh_lookup(drv);
+                devinfo = __scsi_dh_lookup(drv);
         if (devinfo)
                 err = scsi_dh_handler_attach(sdev, devinfo);
         return err;
 }
 
-void scsi_dh_remove_device(struct scsi_device *sdev)
+void scsi_dh_release_device(struct scsi_device *sdev)
 {
         if (sdev->handler)
                 scsi_dh_handler_detach(sdev);
+}
+
+void scsi_dh_remove_device(struct scsi_device *sdev)
+{
         device_remove_file(&sdev->sdev_gendev, &scsi_dh_state_attr);
 }
 
diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h
index 644bb7339b55..4d01cdb1b348 100644
--- a/drivers/scsi/scsi_priv.h
+++ b/drivers/scsi/scsi_priv.h
@@ -173,9 +173,11 @@ extern struct async_domain scsi_sd_probe_domain;
 /* scsi_dh.c */
 #ifdef CONFIG_SCSI_DH
 int scsi_dh_add_device(struct scsi_device *sdev);
+void scsi_dh_release_device(struct scsi_device *sdev);
 void scsi_dh_remove_device(struct scsi_device *sdev);
 #else
 static inline int scsi_dh_add_device(struct scsi_device *sdev) { return 0; }
+static inline void scsi_dh_release_device(struct scsi_device *sdev) { }
 static inline void scsi_dh_remove_device(struct scsi_device *sdev) { }
 #endif
 
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index b333389f248f..dff8fafb741c 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -399,6 +399,8 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work)
 
         sdev = container_of(work, struct scsi_device, ew.work);
 
+        scsi_dh_release_device(sdev);
+
         parent = sdev->sdev_gendev.parent;
 
         spin_lock_irqsave(sdev->host->host_lock, flags);