From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E4970CCA487 for ; Mon, 18 Jul 2022 00:33:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232987AbiGRAdh (ORCPT ); Sun, 17 Jul 2022 20:33:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39082 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233113AbiGRAdJ (ORCPT ); Sun, 17 Jul 2022 20:33:09 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E41831570F for ; Sun, 17 Jul 2022 17:32:56 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 6B17CB80EF2 for ; Mon, 18 Jul 2022 00:32:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 105B3C341C0; Mon, 18 Jul 2022 00:32:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1658104374; bh=qnxZaG8HptYXm2n463/m+1eKZVZZhfx5ubr7qQwBaoY=; h=Date:To:From:Subject:From; b=mrpUhr42XrcpBz7UvPr1vGVcDdizg0VYRCvMsM48DMVZjA8Xi5HKtWwMbVrqnn2NW +M0NdwcHqZsGS9TBDimMJ337jtvmbw19kAfMLcPaEOJiCD/ioUqG0VExiUA+gtcSJ5 ixaDiAMiyzQWOicKuzvIVy3IAL5odbKoF5bEDHU0= Date: Sun, 17 Jul 2022 17:32:53 -0700 To: mm-commits@vger.kernel.org, skhan@linuxfoundation.org, dylanbhatch@google.com, adobriyan@gmail.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-nonmm-stable] proc-fix-test-for-vsyscall=xonly-boot-option.patch removed from -mm tree Message-Id: <20220718003254.105B3C341C0@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The quilt patch titled Subject: proc: fix test for "vsyscall=xonly" boot option has been removed from the -mm tree. Its filename was proc-fix-test-for-vsyscall=xonly-boot-option.patch This patch was dropped because it was merged into the mm-nonmm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Alexey Dobriyan Subject: proc: fix test for "vsyscall=xonly" boot option Date: Tue, 12 Jul 2022 17:51:45 +0300 Booting with vsyscall=xonly results in the following vsyscall VMA: ffffffffff600000-ffffffffff601000 --xp ... [vsyscall] Test does read from fixed vsyscall address to determine if kernel supports vsyscall page but it doesn't work because, well, vsyscall page is execute only. Fix test by trying to execute from the first byte of the page which contains gettimeofday() stub. This should work because vsyscall entry points have stable addresses by design. Alexey, avoiding parsing .config, /proc/config.gz and /proc/cmdline at all costs. Link: https://lkml.kernel.org/r/Ys2KgeiEMboU8Ytu@localhost.localdomain Signed-off-by: Alexey Dobriyan Cc: Shuah Khan Cc: Signed-off-by: Andrew Morton --- tools/testing/selftests/proc/proc-pid-vm.c | 75 +++++++++++++++++-- 1 file changed, 68 insertions(+), 7 deletions(-) --- a/tools/testing/selftests/proc/proc-pid-vm.c~proc-fix-test-for-vsyscall=xonly-boot-option +++ a/tools/testing/selftests/proc/proc-pid-vm.c @@ -211,10 +211,19 @@ static int make_exe(const uint8_t *paylo } #endif -static bool g_vsyscall = false; +/* + * 0: vsyscall VMA doesn't exist vsyscall=none + * 1: vsyscall VMA is r-xp vsyscall=emulate + * 2: vsyscall VMA is --xp vsyscall=xonly + */ +static int g_vsyscall; +static const char *str_vsyscall; -static const char str_vsyscall[] = +static const char str_vsyscall_0[] = ""; +static const char str_vsyscall_1[] = "ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall]\n"; +static const char str_vsyscall_2[] = +"ffffffffff600000-ffffffffff601000 --xp 00000000 00:00 0 [vsyscall]\n"; #ifdef __x86_64__ static void sigaction_SIGSEGV(int _, siginfo_t *__, void *___) @@ -223,7 +232,7 @@ static void sigaction_SIGSEGV(int _, sig } /* - * vsyscall page can't be unmapped, probe it with memory load. + * vsyscall page can't be unmapped, probe it directly. */ static void vsyscall(void) { @@ -246,13 +255,52 @@ static void vsyscall(void) act.sa_sigaction = sigaction_SIGSEGV; (void)sigaction(SIGSEGV, &act, NULL); + /* gettimeofday(NULL, NULL); */ + asm volatile ( + "call %P0" + : + : "i" (0xffffffffff600000), "D" (NULL), "S" (NULL) + : "rax", "rcx", "r11" + ); + exit(0); + } + waitpid(pid, &wstatus, 0); + if (WIFEXITED(wstatus) && WEXITSTATUS(wstatus) == 0) { + /* vsyscall page exists and is executable. */ + } else { + /* vsyscall page doesn't exist. */ + g_vsyscall = 0; + return; + } + + pid = fork(); + if (pid < 0) { + fprintf(stderr, "fork, errno %d\n", errno); + exit(1); + } + if (pid == 0) { + struct rlimit rlim = {0, 0}; + (void)setrlimit(RLIMIT_CORE, &rlim); + + /* Hide "segfault at ffffffffff600000" messages. */ + struct sigaction act; + memset(&act, 0, sizeof(struct sigaction)); + act.sa_flags = SA_SIGINFO; + act.sa_sigaction = sigaction_SIGSEGV; + (void)sigaction(SIGSEGV, &act, NULL); + *(volatile int *)0xffffffffff600000UL; exit(0); } waitpid(pid, &wstatus, 0); if (WIFEXITED(wstatus) && WEXITSTATUS(wstatus) == 0) { - g_vsyscall = true; + /* vsyscall page is readable and executable. */ + g_vsyscall = 1; + return; } + + /* vsyscall page is executable but unreadable. */ + g_vsyscall = 2; } int main(void) @@ -261,6 +309,19 @@ int main(void) int exec_fd; vsyscall(); + switch (g_vsyscall) { + case 0: + str_vsyscall = str_vsyscall_0; + break; + case 1: + str_vsyscall = str_vsyscall_1; + break; + case 2: + str_vsyscall = str_vsyscall_2; + break; + default: + abort(); + } atexit(ate); @@ -314,7 +375,7 @@ int main(void) /* Test /proc/$PID/maps */ { - const size_t len = strlen(buf0) + (g_vsyscall ? strlen(str_vsyscall) : 0); + const size_t len = strlen(buf0) + strlen(str_vsyscall); char buf[256]; ssize_t rv; int fd; @@ -327,7 +388,7 @@ int main(void) rv = read(fd, buf, sizeof(buf)); assert(rv == len); assert(memcmp(buf, buf0, strlen(buf0)) == 0); - if (g_vsyscall) { + if (g_vsyscall > 0) { assert(memcmp(buf + strlen(buf0), str_vsyscall, strlen(str_vsyscall)) == 0); } } @@ -374,7 +435,7 @@ int main(void) assert(memmem(buf, rv, S[i], strlen(S[i]))); } - if (g_vsyscall) { + if (g_vsyscall > 0) { assert(memmem(buf, rv, str_vsyscall, strlen(str_vsyscall))); } } _ Patches currently in -mm which might be from adobriyan@gmail.com are