Patch "selftests/x86: Do not rely on "int $0x80" in single_step_syscall.c" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    selftests/x86: Do not rely on "int $0x80" in single_step_syscall.c

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     selftests-x86-do-not-rely-on-int-0x80-in-single_step_syscall.c.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 4105c69703cdeba76f384b901712c9397b04e9c2 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski <linux@dominikbrodowski.net>
Date: Tue, 13 Feb 2018 09:13:21 +0100
Subject: selftests/x86: Do not rely on "int $0x80" in single_step_syscall.c

From: Dominik Brodowski <linux@dominikbrodowski.net>

commit 4105c69703cdeba76f384b901712c9397b04e9c2 upstream.

On 64-bit builds, we should not rely on "int $0x80" working (it only does if
CONFIG_IA32_EMULATION=y is enabled). To keep the "Set TF and check int80"
test running on 64-bit installs with CONFIG_IA32_EMULATION=y enabled, build
this test only if we can also build 32-bit binaries (which should be a
good approximation for that).

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dmitry Safonov <dsafonov@virtuozzo.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kselftest@vger.kernel.org
Cc: shuah@kernel.org
Link: http://lkml.kernel.org/r/20180211111013.16888-5-linux@dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 tools/testing/selftests/x86/Makefile              |    2 ++
 tools/testing/selftests/x86/single_step_syscall.c |    5 ++++-
 2 files changed, 6 insertions(+), 1 deletion(-)

--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -26,11 +26,13 @@ CAN_BUILD_X86_64 := $(shell ./check_cc.s
 ifeq ($(CAN_BUILD_I386),1)
 all: all_32
 TEST_PROGS += $(BINARIES_32)
+EXTRA_CFLAGS += -DCAN_BUILD_32
 endif
 
 ifeq ($(CAN_BUILD_X86_64),1)
 all: all_64
 TEST_PROGS += $(BINARIES_64)
+EXTRA_CFLAGS += -DCAN_BUILD_64
 endif
 
 all_32: $(BINARIES_32)
--- a/tools/testing/selftests/x86/single_step_syscall.c
+++ b/tools/testing/selftests/x86/single_step_syscall.c
@@ -119,7 +119,9 @@ static void check_result(void)
 
 int main()
 {
+#ifdef CAN_BUILD_32
 	int tmp;
+#endif
 
 	sethandler(SIGTRAP, sigtrap, 0);
 
@@ -139,12 +141,13 @@ int main()
 		      : : "c" (post_nop) : "r11");
 	check_result();
 #endif
-
+#ifdef CAN_BUILD_32
 	printf("[RUN]\tSet TF and check int80\n");
 	set_eflags(get_eflags() | X86_EFLAGS_TF);
 	asm volatile ("int $0x80" : "=a" (tmp) : "a" (SYS_getpid)
 			: INT80_CLOBBERS);
 	check_result();
+#endif
 
 	/*
 	 * This test is particularly interesting if fast syscalls use


Patches currently in stable-queue which might be from linux@dominikbrodowski.net are

queue-4.9/selftests-x86-do-not-rely-on-int-0x80-in-single_step_syscall.c.patch
queue-4.9/selftests-x86-do-not-rely-on-int-0x80-in-test_mremap_vdso.c.patch