Patch "acpi/nfit: Fix memory corruption/Unregister mce decoder on failure" has been added to the 4.9-stable tree

Patch "acpi/nfit: Fix memory corruption/Unregister mce decoder on failure" 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

    acpi/nfit: Fix memory corruption/Unregister mce decoder on failure

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:
     acpi-nfit-fix-memory-corruption-unregister-mce-decoder-on-failure.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 7e700d2c59e5853c9126642976b4f5768f64c9b3 Mon Sep 17 00:00:00 2001
From: Prarit Bhargava <prarit@redhat.com>
Date: Wed, 31 May 2017 13:32:00 -0400
Subject: acpi/nfit: Fix memory corruption/Unregister mce decoder on failure

From: Prarit Bhargava <prarit@redhat.com>

commit 7e700d2c59e5853c9126642976b4f5768f64c9b3 upstream.

nfit_init() calls nfit_mce_register() on module load.  When the module
load fails the nfit mce decoder is not unregistered.  The module's
memory is freed leaving the decoder chain referencing junk.  This will
cause panics as future registrations will reference the free'd memory.

Unregister the nfit mce decoder on module init failure.

[v2]: register and then unregister mce handler to avoid losing mce events
[v3]: also cleanup nfit workqueue

Fixes: 6839a6d96f4e ("nfit: do an ARS scrub on hitting a latent media error")
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: "Lee, Chun-Yi" <joeyli.kernel@gmail.com>
Cc: Linda Knippers <linda.knippers@hpe.com>
Cc: lszubowi@redhat.com
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/acpi/nfit/core.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -2945,6 +2945,8 @@ static struct acpi_driver acpi_nfit_driv
 
 static __init int nfit_init(void)
 {
+	int ret;
+
 	BUILD_BUG_ON(sizeof(struct acpi_table_nfit) != 40);
 	BUILD_BUG_ON(sizeof(struct acpi_nfit_system_address) != 56);
 	BUILD_BUG_ON(sizeof(struct acpi_nfit_memory_map) != 48);
@@ -2972,8 +2974,14 @@ static __init int nfit_init(void)
 		return -ENOMEM;
 
 	nfit_mce_register();
+	ret = acpi_bus_register_driver(&acpi_nfit_driver);
+	if (ret) {
+		nfit_mce_unregister();
+		destroy_workqueue(nfit_wq);
+	}
+
+	return ret;
 
-	return acpi_bus_register_driver(&acpi_nfit_driver);
 }
 
 static __exit void nfit_exit(void)


Patches currently in stable-queue which might be from prarit@redhat.com are

queue-4.9/acpi-nfit-fix-memory-corruption-unregister-mce-decoder-on-failure.patch