patch "mei: discard messages from not connected client during power down." added to char-misc-linus

[<gregkh@linuxfoundation.org>]

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

    mei: discard messages from not connected client during power down.

to my char-misc git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


>From b7a020bff31318fc8785e6f96b1d38c1625cf1fb Mon Sep 17 00:00:00 2001
From: Alexander Usyskin <alexander.usyskin@intel.com>
Date: Thu, 7 Jun 2018 00:31:48 +0300
Subject: mei: discard messages from not connected client during power down.

This fixes regression introduced by
commit 8d52af6795c0 ("mei: speed up the power down flow")

In power down or suspend flow a message can still be received
from the FW because the clients fake disconnection.
In normal case we interpret messages w/o destination as corrupted
and link reset is performed in order to clean the channel,
but during power down link reset is already in progress resulting
in endless loop. To resolve the issue under power down flow we
discard messages silently.

Cc: <stable@vger.kernel.org> 4.16+
Fixes: 8d52af6795c0 ("mei: speed up the power down flow")
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=199541
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/interrupt.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/mei/interrupt.c b/drivers/misc/mei/interrupt.c
index b0b8f18a85e3..6649f0d56d2f 100644
--- a/drivers/misc/mei/interrupt.c
+++ b/drivers/misc/mei/interrupt.c
@@ -310,8 +310,11 @@ int mei_irq_read_handler(struct mei_device *dev,
 	if (&cl->link == &dev->file_list) {
 		/* A message for not connected fixed address clients
 		 * should be silently discarded
+		 * On power down client may be force cleaned,
+		 * silently discard such messages
 		 */
-		if (hdr_is_fixed(mei_hdr)) {
+		if (hdr_is_fixed(mei_hdr) ||
+		    dev->dev_state == MEI_DEV_POWER_DOWN) {
 			mei_irq_discard_msg(dev, mei_hdr);
 			ret = 0;
 			goto reset_slots;
-- 
2.18.0