Commit 158b67b5 authored May 03, 2016 by Andy Lutomirski Committed by Ingo Molnar May 04, 2016

selftests/sigaltstack: Fix the sigaltstack test on old kernels

The handling for old kernels was wrong, resulting in a segfault.  Fix it.

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
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: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Stas Sergeev <stsp@list.ru>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-api@vger.kernel.org
Link: http://lkml.kernel.org/r/f3e739bf435beeaecbd5f038f1359d2eac6d1e63.1462296606.git.luto@kernel.org

Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent c876eeab

tools/testing/selftests/sigaltstack/sas.c

+14 −7

Original line number	Diff line number	Diff line
		@@ -15,6 +15,7 @@
		#include <alloca.h>
		#include <string.h>
		#include <assert.h>
		#include <errno.h>

		#ifndef SS_AUTODISARM
		#define SS_AUTODISARM (1 << 4)
		@@ -117,14 +118,20 @@ int main(void)
		stk.ss_flags = SS_ONSTACK \| SS_AUTODISARM;
		err = sigaltstack(&stk, NULL);
		if (err) {
		if (errno == EINVAL) {
		printf("[NOTE]\tThe running kernel doesn't support SS_AUTODISARM\n");
		/*
		* If test cases for the !SS_AUTODISARM variant were
		* added, we could still run them. We don't have any
		* test cases like that yet, so just exit and report
		* success.
		*/
		return 0;
		} else {
		perror("[FAIL]\tsigaltstack(SS_ONSTACK \| SS_AUTODISARM)");
		stk.ss_flags = SS_ONSTACK;
		}
		err = sigaltstack(&stk, NULL);
		if (err) {
		perror("[FAIL]\tsigaltstack(SS_ONSTACK)");
		return EXIT_FAILURE;
		}
		}

		ustack = mmap(NULL, SIGSTKSZ, PROT_READ \| PROT_WRITE,
		MAP_PRIVATE \| MAP_ANONYMOUS \| MAP_STACK, -1, 0);