[tip:x86/urgent] x86/ldt: Initialize the context lock for init_mm

[tip-bot for Sebastian Andrzej Siewior]

Commit-ID:  32232b350d7cd93cdc65fe5a453e6a40b539e9f9
Gitweb:     https://git.kernel.org/tip/32232b350d7cd93cdc65fe5a453e6a40b539e9f9
Author:     Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
AuthorDate: Mon, 1 Jul 2019 19:33:54 +0200
Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Wed, 3 Jul 2019 10:25:04 +0200

x86/ldt: Initialize the context lock for init_mm

The mutex mm->context->lock for init_mm is not initialized for init_mm.
This wasn't a problem because it remained unused. This changed however
since commit
	4fc19708b165c ("x86/alternatives: Initialize temporary mm for patching")

Initialize the mutex for init_mm.

Fixes: 4fc19708b165c ("x86/alternatives: Initialize temporary mm for patching")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Nadav Amit <namit@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20190701173354.2pe62hhliok2afea@xxxxxxxxxxxxx

---
 arch/x86/include/asm/mmu.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h
index 5ff3e8af2c20..e78c7db87801 100644
--- a/arch/x86/include/asm/mmu.h
+++ b/arch/x86/include/asm/mmu.h
@@ -59,6 +59,7 @@ typedef struct {
 #define INIT_MM_CONTEXT(mm)						\
 	.context = {							\
 		.ctx_id = 1,						\
+		.lock = __MUTEX_INITIALIZER(mm.context.lock),		\
 	}
 
 void leave_mm(int cpu);