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

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: 71edf4932b91 ("nfit: do an ARS scrub on hitting a latent media error")
Cc: <stable@vger.kernel.org>
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>

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index b75b734ee73addc621c26710d8dfed1cbbe05fba..19182d091587382e0b94e9354f9c442ea90624a3 100644 (file)
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -3160,6 +3160,8 @@ static struct acpi_driver acpi_nfit_driver = {
 
 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);
@@ -3187,8 +3189,14 @@ 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)