[patch 1/3] x86/ldt: Free the right LDT memory in write_ldt() error path

From: Thomas Gleixner
Date: Sat Dec 30 2017 - 16:22:46 EST


The error path in write_ldt() frees the already installed LDT memory
instead of the newly allocated which cannot be installed.

Fixes: f55f0501cbf6 ("x86/pti: Put the LDT in its own PGD if PTI is on")
Reported-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/kernel/ldt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -421,7 +421,7 @@ static int write_ldt(void __user *ptr, u
*/
error = map_ldt_struct(mm, new_ldt, old_ldt ? !old_ldt->slot : 0);
if (error) {
- free_ldt_struct(old_ldt);
+ free_ldt_struct(new_ldt);
goto out_unlock;
}