[tip:x86/asm] x86/arch_prctl/64: Restore accidentally removed put_cpu() in ARCH_SET_GS

[tip-bot for Mateusz Guzik <tipbot@zytor.com>]

Commit-ID:  4afd0565552c87f23834db9121dd9cf6955d0b43
Gitweb:     http://git.kernel.org/tip/4afd0565552c87f23834db9121dd9cf6955d0b43
Author:     Mateusz Guzik <mguzik@redhat.com>
AuthorDate: Tue, 10 May 2016 22:56:43 +0200
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 13 May 2016 13:50:15 +0200

x86/arch_prctl/64: Restore accidentally removed put_cpu() in ARCH_SET_GS

This fixes an oversight in:

	731e33e39a5b95 ("Remove FSBASE/GSBASE < 4G optimization")

Signed-off-by: Mateusz Guzik <mguzik@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1462913803-29634-1-git-send-email-mguzik@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/process_64.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 4285f6a..6b16c36 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -541,6 +541,7 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
 			load_gs_index(0);
 			ret = wrmsrl_safe(MSR_KERNEL_GS_BASE, addr);
 		}
+		put_cpu();
 		break;
 	case ARCH_SET_FS:
 		/* Not strictly needed for fs, but do it for symmetry