Patch "mei: amthif: discard not read messages" has been added to the 4.6-stable tree

Patch "mei: amthif: discard not read messages" has been added to the 4.6-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    mei: amthif: discard not read messages

to the 4.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mei-amthif-discard-not-read-messages.patch
and it can be found in the queue-4.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 9d04ee11db7bf0d848266cbfd7db336097a0e239 Mon Sep 17 00:00:00 2001
From: Alexander Usyskin <alexander.usyskin@intel.com>
Date: Sun, 17 Apr 2016 12:16:04 -0400
Subject: mei: amthif: discard not read messages

From: Alexander Usyskin <alexander.usyskin@intel.com>

commit 9d04ee11db7bf0d848266cbfd7db336097a0e239 upstream.

When a message is received and amthif client is not in reading state
the message is ignored and left dangling in the queue. This may happen
after one of the amthif host connections is closed w/o completing the
reading. Another client will pick up a wrong message on next read
attempt which will lead to link reset.
To prevent this the driver has to properly discard the message when
amthif client is not in reading state.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/misc/mei/amthif.c    |    4 +++-
 drivers/misc/mei/interrupt.c |    1 -
 drivers/misc/mei/mei_dev.h   |    2 ++
 3 files changed, 5 insertions(+), 2 deletions(-)

--- a/drivers/misc/mei/amthif.c
+++ b/drivers/misc/mei/amthif.c
@@ -380,8 +380,10 @@ int mei_amthif_irq_read_msg(struct mei_c
 
 	dev = cl->dev;
 
-	if (dev->iamthif_state != MEI_IAMTHIF_READING)
+	if (dev->iamthif_state != MEI_IAMTHIF_READING) {
+		mei_irq_discard_msg(dev, mei_hdr);
 		return 0;
+	}
 
 	ret = mei_cl_irq_read_msg(cl, mei_hdr, cmpl_list);
 	if (ret)
--- a/drivers/misc/mei/interrupt.c
+++ b/drivers/misc/mei/interrupt.c
@@ -76,7 +76,6 @@ static inline int mei_cl_hbm_equal(struc
  * @dev: mei device
  * @hdr: message header
  */
-static inline
 void mei_irq_discard_msg(struct mei_device *dev, struct mei_msg_hdr *hdr)
 {
 	/*
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -704,6 +704,8 @@ bool mei_hbuf_acquire(struct mei_device
 
 bool mei_write_is_idle(struct mei_device *dev);
 
+void mei_irq_discard_msg(struct mei_device *dev, struct mei_msg_hdr *hdr);
+
 #if IS_ENABLED(CONFIG_DEBUG_FS)
 int mei_dbgfs_register(struct mei_device *dev, const char *name);
 void mei_dbgfs_deregister(struct mei_device *dev);


Patches currently in stable-queue which might be from alexander.usyskin@intel.com are

queue-4.6/mei-fix-null-dereferencing-during-fw-initiated-disconnection.patch
queue-4.6/mei-amthif-discard-not-read-messages.patch
queue-4.6/mei-bus-call-mei_cl_read_start-under-device-lock.patch