[PATCH 1/1 linux-next] ACPI / extlog: avoid null pointer dereference

[Fabian Frederick]

extlog_l1_addr was checked after assigning flags attribute.

Signed-off-by: Fabian Frederick <f...@skynet.be>
---
 drivers/acpi/acpi_extlog.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/acpi_extlog.c b/drivers/acpi/acpi_extlog.c
index b3842ff..183b7b2 100644
--- a/drivers/acpi/acpi_extlog.c
+++ b/drivers/acpi/acpi_extlog.c
@@ -309,9 +309,10 @@ static void __exit extlog_exit(void)
 {
        set_edac_report_status(old_edac_report_status);
        mce_unregister_decode_chain(&extlog_mce_dec);
-       ((struct extlog_l1_head *)extlog_l1_addr)->flags &= ~FLAG_OS_OPTIN;
-       if (extlog_l1_addr)
+       if (extlog_l1_addr) {
+               ((struct extlog_l1_head *)extlog_l1_addr)->flags &= 
~FLAG_OS_OPTIN;
                acpi_os_unmap_iomem(extlog_l1_addr, l1_size);
+       }
        if (elog_addr)
                acpi_os_unmap_iomem(elog_addr, elog_size);
        release_mem_region(elog_base, elog_size);
-- 
2.1.4