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authorThomas Gleixner <tglx@linutronix.de>2017-12-31 16:52:15 +0100
committerThomas Gleixner <tglx@linutronix.de>2017-12-31 16:55:09 +0100
commit7f414195b0c3612acd12b4611a5fe75995cf10c7 (patch)
tree0fb83d6e1283ec3e3963e14d34573c22e474bbdd /arch/x86/kernel/ldt.c
parenta62d69857aab4caa43049e72fe0ed5c4a60518dd (diff)
downloadlinux-7f414195b0c3612acd12b4611a5fe75995cf10c7.tar.gz
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>
Diffstat (limited to 'arch/x86/kernel/ldt.c')
-rw-r--r--arch/x86/kernel/ldt.c3
1 files changed, 2 insertions, 1 deletions
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;
 	}