From a555ad450f973528825201a5fedbe46374f86644 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Mon, 23 Feb 2015 03:21:31 -0500
Subject: [PATCH] whack-a-mole: no need to set_fs(USER_DS) in
 {start,flush}_thread()

flush_old_exec() has already done that.  Back on 2011 a bunch of
instances like that had been kicked out, but that hadn't taken
care of then-out-of-tree architectures, obviously, and they served
as reinfection vector...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/arc/kernel/process.c          | 2 --
 arch/c6x/kernel/process.c          | 1 -
 arch/hexagon/kernel/process.c      | 2 --
 arch/metag/include/asm/processor.h | 1 -
 arch/nios2/kernel/process.c        | 1 -
 arch/openrisc/kernel/process.c     | 1 -
 6 files changed, 8 deletions(-)

diff --git a/arch/arc/kernel/process.c b/arch/arc/kernel/process.c
index 98c00a2d4dd9..f46efd14059d 100644
--- a/arch/arc/kernel/process.c
+++ b/arch/arc/kernel/process.c
@@ -155,8 +155,6 @@ int copy_thread(unsigned long clone_flags,
  */
 void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long usp)
 {
-	set_fs(USER_DS); /* user space */
-
 	regs->sp = usp;
 	regs->ret = pc;
 
diff --git a/arch/c6x/kernel/process.c b/arch/c6x/kernel/process.c
index 57d2ea8d1977..3ae9f5a166a0 100644
--- a/arch/c6x/kernel/process.c
+++ b/arch/c6x/kernel/process.c
@@ -101,7 +101,6 @@ void start_thread(struct pt_regs *regs, unsigned int pc, unsigned long usp)
 	 */
 	usp -= 8;
 
-	set_fs(USER_DS);
 	regs->pc  = pc;
 	regs->sp  = usp;
 	regs->tsr |= 0x40; /* set user mode */
diff --git a/arch/hexagon/kernel/process.c b/arch/hexagon/kernel/process.c
index 0a0dd5c05b46..a9ebd471823a 100644
--- a/arch/hexagon/kernel/process.c
+++ b/arch/hexagon/kernel/process.c
@@ -37,8 +37,6 @@
  */
 void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
 {
-	/* Set to run with user-mode data segmentation */
-	set_fs(USER_DS);
 	/* We want to zero all data-containing registers. Is this overkill? */
 	memset(regs, 0, sizeof(*regs));
 	/* We might want to also zero all Processor registers here */
diff --git a/arch/metag/include/asm/processor.h b/arch/metag/include/asm/processor.h
index 13272fd5a5ba..0838ca699764 100644
--- a/arch/metag/include/asm/processor.h
+++ b/arch/metag/include/asm/processor.h
@@ -111,7 +111,6 @@ struct thread_struct {
  */
 #define start_thread(regs, pc, usp) do {				   \
 	unsigned int *argc = (unsigned int *) bprm->exec;		   \
-	set_fs(USER_DS);						   \
 	current->thread.int_depth = 1;					   \
 	/* Force this process down to user land */			   \
 	regs->ctx.SaveMask = TBICTX_PRIV_BIT;				   \
diff --git a/arch/nios2/kernel/process.c b/arch/nios2/kernel/process.c
index 0e075b5ad2a5..2f8c74f93e70 100644
--- a/arch/nios2/kernel/process.c
+++ b/arch/nios2/kernel/process.c
@@ -94,7 +94,6 @@ void show_regs(struct pt_regs *regs)
 
 void flush_thread(void)
 {
-	set_fs(USER_DS);
 }
 
 int copy_thread(unsigned long clone_flags,
diff --git a/arch/openrisc/kernel/process.c b/arch/openrisc/kernel/process.c
index 386af258591d..7095dfe7666b 100644
--- a/arch/openrisc/kernel/process.c
+++ b/arch/openrisc/kernel/process.c
@@ -197,7 +197,6 @@ void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
 {
 	unsigned long sr = mfspr(SPR_SR) & ~SPR_SR_SM;
 
-	set_fs(USER_DS);
 	memset(regs, 0, sizeof(struct pt_regs));
 
 	regs->pc = pc;