EDAC: Fix kernel panic on module unloading

This patch fixes use-after-free and double-free bugs in
edac_mc_sysfs_exit(). mci_pdev has single reference and put_device()
calls mc_attr_release() which calls kfree(). The following
device_del() works with already released memory. An another kfree() in
edac_mc_sysfs_exit() releses the same memory again. Great.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: stable@vger.kernel.org # 3.[67]
Cc: Denis Kirjanov <kirjanov@gmail.com>
Cc: Mauro Carvalho Chehab <mchehab@redhat.com>
Link: http://lkml.kernel.org/r/20121214110310.11019.21098.stgit@zurg
Signed-off-by: Borislav Petkov <bp@alien8.de>

1 files changed, 1 insertions, 2 deletions

diff --git a/drivers/edac/edac_mc_sysfs.c b/drivers/edac/edac_mc_sysfs.c
index de2df92f9c77..a3b0119ecb00 100644
--- a/drivers/edac/edac_mc_sysfs.c
+++ b/drivers/edac/edac_mc_sysfs.c
@@ -1159,8 +1159,7 @@ int __init edac_mc_sysfs_init(void)
 
 void __exit edac_mc_sysfs_exit(void)
 {
-        put_device(mci_pdev);
         device_del(mci_pdev);
+        put_device(mci_pdev);
         edac_put_sysfs_subsys();
-        kfree(mci_pdev);
 }