[ 187/221] EDAC: Fix kernel panic on module unloading

Greg Kroah-Hartman
2013-01-15T22:35:34Z

From: Konstantin Khlebnikov <khlebnikov@openvz.org>

commit 311bd84247ee0bedae6cdfbfc5e2c3450f9decd1 upstream.

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: 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>
[ a partial 3.7.y backport ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/edac/edac_mc_sysfs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/edac/edac_mc_sysfs.c
+++ b/drivers/edac/edac_mc_sysfs.c
@@ -1145,7 +1145,7 @@ 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();
}