From 7f414195b0c3612acd12b4611a5fe75995cf10c7 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner <tglx@linutronix.de> Date: Sun, 31 Dec 2017 16:52:15 +0100 Subject: [PATCH] x86/ldt: Make LDT pgtable free conditional Andy prefers to be paranoid about the pagetable free in the error path of write_ldt(). Make it conditional and warn whenever the installment of a secondary LDT fails. Requested-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- arch/x86/kernel/ldt.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c index 500e90e44f86..26d713ecad34 100644 --- a/arch/x86/kernel/ldt.c +++ b/arch/x86/kernel/ldt.c @@ -426,7 +426,8 @@ static int write_ldt(void __user *ptr, unsigned long bytecount, int oldmode) * already installed then the PTE page is already * populated. Mop up a half populated page table. */ - free_ldt_pgtables(mm); + if (!WARN_ON_ONCE(old_ldt)) + free_ldt_pgtables(mm); free_ldt_struct(new_ldt); goto out_unlock; } -- GitLab