Revert "arm/syscalls: Check address limit on user-mode return"

This reverts commit 73ac5d6a2b6ac3ae8d1e1818f3e9946f97489bc9.

The work pending loop can call set_fs after addr_limit_user_check
removed the _TIF_FSCHECK flag. This may happen at anytime based on how
ARM handles alignment exceptions. It leads to an infinite loop condition.

After discussion, it has been agreed that the generic approach is not
tailored to the ARM architecture and any fix might not be complete. This
patch will be replaced by an architecture specific implementation. The
work flag approach will be kept for other architectures.

Reported-by: Leonard Crestez <[email protected]>
Signed-off-by: Thomas Garnier <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Pratyush Anand <[email protected]>
Cc: Dave Martin <[email protected]>
Cc: Will Drewry <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Russell King <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: David Howells <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Al Viro <[email protected]>
Cc: [email protected]
Cc: Yonghong Song <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]

1 files changed, 0 insertions, 5 deletions

diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index e2de50bf8742..5814298ef0b7 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -14,7 +14,6 @@
 #include <linux/uaccess.h>
 #include <linux/tracehook.h>
 #include <linux/uprobes.h>
-#include <linux/syscalls.h>
 
 #include <asm/elf.h>
 #include <asm/cacheflush.h>
@@ -614,10 +613,6 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
 	 * Update the trace code with the current status.
 	 */
 	trace_hardirqs_off();
-
-	/* Check valid user FS if needed */
-	addr_limit_user_check();
-
 	do {
 		if (likely(thread_flags & _TIF_NEED_RESCHED)) {
 			schedule();