MdeModulePkg PartitionDxe: Add Re-entry handling logic for BindingStop

There are scenario when the BindingStop service of PartitionDxe driver be
re-entered.

An example will be ejecting a DVD from a SATA DVDROM and then run
"reconnect -r" under shell. In this specific case, part of the calling
stack will be:

PartitionDriverBindingStop() (PartitionDxe) ->
Stop first child handle (PartitionDxe) ->
ScsiDiskFlushBlocksEx() (ScsiDiskDxe) ->
A media change is detected (ScsiDiskDxe) ->
Reinstall of BlockIO(2) protocols (ScsiDiskDxe) ->
Entering PartitionDriverBindingStop() again (PartitionDxe) ->
Potential risk of referencing already stopped child handle (PartitionDxe)
...

The current code has potential issue of referencing of already stopped
child handle. This commit adds re-entry handling logic to resolve such
issue.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>

2 files changed, 110 insertions, 21 deletions

diff --git a/MdeModulePkg/Universal/Disk/PartitionDxe/Partition.c b/MdeModulePkg/Universal/Disk/PartitionDxe/Partition.c
index 89cc540..1c53bf0 100644
--- a/MdeModulePkg/Universal/Disk/PartitionDxe/Partition.c
+++ b/MdeModulePkg/Universal/Disk/PartitionDxe/Partition.c
@@ -408,6 +408,16 @@ PartitionDriverBindingStop (
 

   if (NumberOfChildren == 0) {

     //

+    // In the case of re-entry of the PartitionDriverBindingStop, the

+    // NumberOfChildren may not reflect the actual number of children on the

+    // bus driver. Hence, additional check is needed here.

+    //

+    if (HasChildren (ControllerHandle)) {

+      DEBUG((EFI_D_ERROR, "PartitionDriverBindingStop: Still has child.\n"));

+      return EFI_DEVICE_ERROR;

+    }

+

+    //

     // Close the bus driver

     //

     gBS->CloseProtocol (

@@ -459,35 +469,57 @@ PartitionDriverBindingStop (
 

 

     Private = PARTITION_DEVICE_FROM_BLOCK_IO_THIS (BlockIo);

+    if (Private->InStop) {

+      //

+      // If the child handle is going to be stopped again during the re-entry

+      // of DriverBindingStop, just do nothing.

+      //

+      break;

+    }

+    Private->InStop = TRUE;

 

-    Status = gBS->CloseProtocol (

-                    ControllerHandle,

-                    &gEfiDiskIoProtocolGuid,

-                    This->DriverBindingHandle,

-                    ChildHandleBuffer[Index]

-                    );

+    BlockIo->FlushBlocks (BlockIo);

+

+    if (BlockIo2 != NULL) {

+      Status = BlockIo2->FlushBlocksEx (BlockIo2, NULL);

+      DEBUG((EFI_D_ERROR, "PartitionDriverBindingStop: FlushBlocksEx returned with %r\n", Status));

+    } else {

+      Status = EFI_SUCCESS;

+    }

+

+    gBS->CloseProtocol (

+           ControllerHandle,

+           &gEfiDiskIoProtocolGuid,

+           This->DriverBindingHandle,

+           ChildHandleBuffer[Index]

+           );

     //

     // All Software protocols have be freed from the handle so remove it.

     // Remove the BlockIo Protocol if has.

     // Remove the BlockIo2 Protocol if has.

     //

     if (BlockIo2 != NULL) {

-      BlockIo->FlushBlocks (BlockIo);

-      BlockIo2->FlushBlocksEx (BlockIo2, NULL);

-      Status = gBS->UninstallMultipleProtocolInterfaces (

-                       ChildHandleBuffer[Index],

-                       &gEfiDevicePathProtocolGuid,

-                       Private->DevicePath,

-                       &gEfiBlockIoProtocolGuid,

-                       &Private->BlockIo,

-                       &gEfiBlockIo2ProtocolGuid,

-                       &Private->BlockIo2,

-                       Private->EspGuid,

-                       NULL,

-                       NULL

-                       );

+      //

+      // Some device drivers might re-install the BlockIO(2) protocols for a

+      // media change condition. Therefore, if the FlushBlocksEx returned with

+      // EFI_MEDIA_CHANGED, just let the BindingStop fail to avoid potential

+      // reference of already stopped child handle.

+      //

+      if (Status != EFI_MEDIA_CHANGED) {

+        Status = gBS->UninstallMultipleProtocolInterfaces (

+                         ChildHandleBuffer[Index],

+                         &gEfiDevicePathProtocolGuid,

+                         Private->DevicePath,

+                         &gEfiBlockIoProtocolGuid,

+                         &Private->BlockIo,

+                         &gEfiBlockIo2ProtocolGuid,

+                         &Private->BlockIo2,

+                         Private->EspGuid,

+                         NULL,

+                         NULL

+                         );

+      }

     } else {

-      BlockIo->FlushBlocks (BlockIo);

       Status = gBS->UninstallMultipleProtocolInterfaces (

                        ChildHandleBuffer[Index],

                        &gEfiDevicePathProtocolGuid,

@@ -501,6 +533,7 @@ PartitionDriverBindingStop (
     }

 

     if (EFI_ERROR (Status)) {

+      Private->InStop = FALSE;

       gBS->OpenProtocol (

              ControllerHandle,

              &gEfiDiskIoProtocolGuid,

@@ -516,6 +549,9 @@ PartitionDriverBindingStop (
 

     if (EFI_ERROR (Status)) {

       AllChildrenStopped = FALSE;

+      if (Status == EFI_MEDIA_CHANGED) {

+        break;

+      }

     }

   }

 

@@ -1263,3 +1299,41 @@ InitializePartition (
   return Status;

 }

 

+

+/**

+  Test to see if there is any child on ControllerHandle.

+

+  @param[in]  ControllerHandle    Handle of device to test.

+

+  @retval TRUE                    There are children on the ControllerHandle.

+  @retval FALSE                   No child is on the ControllerHandle.

+

+**/

+BOOLEAN

+HasChildren (

+  IN EFI_HANDLE           ControllerHandle

+  )

+{

+  EFI_OPEN_PROTOCOL_INFORMATION_ENTRY  *OpenInfoBuffer;

+  UINTN                                EntryCount;

+  EFI_STATUS                           Status;

+  UINTN                                Index;

+

+  Status = gBS->OpenProtocolInformation (

+                  ControllerHandle,

+                  &gEfiDiskIoProtocolGuid,

+                  &OpenInfoBuffer,

+                  &EntryCount

+                  );

+  ASSERT_EFI_ERROR (Status);

+

+  for (Index = 0; Index < EntryCount; Index++) {

+    if ((OpenInfoBuffer[Index].Attributes & EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER) != 0) {

+      break;

+    }

+  }

+  FreePool (OpenInfoBuffer);

+

+  return (BOOLEAN) (Index < EntryCount);

+}

+

diff --git a/MdeModulePkg/Universal/Disk/PartitionDxe/Partition.h b/MdeModulePkg/Universal/Disk/PartitionDxe/Partition.h
index 06470f6..7cb1988 100644
--- a/MdeModulePkg/Universal/Disk/PartitionDxe/Partition.h
+++ b/MdeModulePkg/Universal/Disk/PartitionDxe/Partition.h
@@ -61,6 +61,7 @@ typedef struct {
   UINT64                    Start;

   UINT64                    End;

   UINT32                    BlockSize;

+  BOOLEAN                   InStop;

 

   EFI_GUID                  *EspGuid;

 

@@ -346,6 +347,20 @@ PartitionInstallChildHandle (
   );

 

 /**

+  Test to see if there is any child on ControllerHandle.

+

+  @param[in]  ControllerHandle    Handle of device to test.

+

+  @retval TRUE                    There are children on the ControllerHandle.

+  @retval FALSE                   No child is on the ControllerHandle.

+

+**/

+BOOLEAN

+HasChildren (

+  IN EFI_HANDLE           ControllerHandle

+  );

+

+/**

   Install child handles if the Handle supports GPT partition structure.

 

   @param[in]  This       Calling context.