Patch "staging: greybus: spilib: fix use-after-free after deregistration" has been added to the 4.9-stable tree

Patch "staging: greybus: spilib: fix use-after-free after deregistration" has been added to the 4.9-stable tree

[gregkh]

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

    staging: greybus: spilib: fix use-after-free after deregistration

to the 4.9-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:
     staging-greybus-spilib-fix-use-after-free-after-deregistration.patch
and it can be found in the queue-4.9 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 770b03c2ca4aa44d226cf248f86aa23e546147d0 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Sun, 29 Oct 2017 13:01:33 +0100
Subject: staging: greybus: spilib: fix use-after-free after deregistration

From: Johan Hovold <johan@kernel.org>

commit 770b03c2ca4aa44d226cf248f86aa23e546147d0 upstream.

Remove erroneous spi_master_put() after controller deregistration which
would access the already freed spi controller.

Note that spi_unregister_master() drops our only controller reference.

Fixes: ba3e67001b42 ("greybus: SPI: convert to a gpbridge driver")
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Rui Miguel Silva <rmfrfs@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/staging/greybus/spilib.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

--- a/drivers/staging/greybus/spilib.c
+++ b/drivers/staging/greybus/spilib.c
@@ -544,12 +544,15 @@ int gb_spilib_master_init(struct gb_conn
 
 	return 0;
 
-exit_spi_unregister:
-	spi_unregister_master(master);
 exit_spi_put:
 	spi_master_put(master);
 
 	return ret;
+
+exit_spi_unregister:
+	spi_unregister_master(master);
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(gb_spilib_master_init);
 
@@ -558,7 +561,6 @@ void gb_spilib_master_exit(struct gb_con
 	struct spi_master *master = gb_connection_get_data(connection);
 
 	spi_unregister_master(master);
-	spi_master_put(master);
 }
 EXPORT_SYMBOL_GPL(gb_spilib_master_exit);
 


Patches currently in stable-queue which might be from johan@kernel.org are

queue-4.9/usb-serial-qcserial-add-pid-vid-for-sierra-wireless-em7355-fw-update.patch
queue-4.9/staging-greybus-add-host-device-function-pointer-checks.patch
queue-4.9/staging-greybus-spilib-fix-use-after-free-after-deregistration.patch
queue-4.9/usb-serial-garmin_gps-fix-i-o-after-failed-probe-and-remove.patch
queue-4.9/usb-serial-garmin_gps-fix-memory-leak-on-probe-errors.patch