From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965223AbcDYVjx (ORCPT ); Mon, 25 Apr 2016 17:39:53 -0400 Received: from mail-oi0-f46.google.com ([209.85.218.46]:34370 "EHLO mail-oi0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965159AbcDYVjv (ORCPT ); Mon, 25 Apr 2016 17:39:51 -0400 MIME-Version: 1.0 In-Reply-To: <1461584223-9418-2-git-send-email-dsafonov@virtuozzo.com> References: <1460388169-13340-1-git-send-email-dsafonov@virtuozzo.com> <1461584223-9418-1-git-send-email-dsafonov@virtuozzo.com> <1461584223-9418-2-git-send-email-dsafonov@virtuozzo.com> From: Andy Lutomirski Date: Mon, 25 Apr 2016 14:39:31 -0700 Message-ID: Subject: Re: [PATCHv8 2/2] selftest/x86: add mremap vdso test To: Dmitry Safonov Cc: "linux-kernel@vger.kernel.org" , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , X86 ML , Andrew Morton , "linux-mm@kvack.org" , Dmitry Safonov <0x7f454c46@gmail.com>, Shuah Khan , linux-kselftest@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 25, 2016 at 4:37 AM, Dmitry Safonov wrote: > Should print on success: > [root@localhost ~]# ./test_mremap_vdso_32 > AT_SYSINFO_EHDR is 0xf773f000 > [NOTE] Moving vDSO: [f773f000, f7740000] -> [a000000, a001000] > [OK] > Or segfault if landing was bad (before patches): > [root@localhost ~]# ./test_mremap_vdso_32 > AT_SYSINFO_EHDR is 0xf774f000 > [NOTE] Moving vDSO: [f774f000, f7750000] -> [a000000, a001000] > Segmentation fault (core dumped) Acked-by: Andy Lutomirski Ingo, can you apply this? > > Cc: Shuah Khan > Cc: linux-kselftest@vger.kernel.org > Suggested-by: Andy Lutomirski > Signed-off-by: Dmitry Safonov > --- > v8: run test for x86_64 too; > removed fixed VDSO_SIZE - check EINVAL mremap return for partial remapping > v5: initial version > > tools/testing/selftests/x86/Makefile | 2 +- > tools/testing/selftests/x86/test_mremap_vdso.c | 99 ++++++++++++++++++++++++++ > 2 files changed, 100 insertions(+), 1 deletion(-) > create mode 100644 tools/testing/selftests/x86/test_mremap_vdso.c > > diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile > index b47ebd170690..ba865f2efcce 100644 > --- a/tools/testing/selftests/x86/Makefile > +++ b/tools/testing/selftests/x86/Makefile > @@ -5,7 +5,7 @@ include ../lib.mk > .PHONY: all all_32 all_64 warn_32bit_failure clean > > TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt ptrace_syscall \ > - check_initial_reg_state sigreturn ldt_gdt iopl > + check_initial_reg_state sigreturn ldt_gdt iopl test_mremap_vdso > TARGETS_C_32BIT_ONLY := entry_from_vm86 syscall_arg_fault test_syscall_vdso unwind_vdso \ > test_FCMOV test_FCOMI test_FISTTP \ > vdso_restorer > diff --git a/tools/testing/selftests/x86/test_mremap_vdso.c b/tools/testing/selftests/x86/test_mremap_vdso.c > new file mode 100644 > index 000000000000..831e2e0107d9 > --- /dev/null > +++ b/tools/testing/selftests/x86/test_mremap_vdso.c > @@ -0,0 +1,99 @@ > +/* > + * 32-bit test to check vdso mremap. > + * > + * Copyright (c) 2016 Dmitry Safonov > + * Suggested-by: Andrew Lutomirski > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms and conditions of the GNU General Public License, > + * version 2, as published by the Free Software Foundation. > + * > + * This program is distributed in the hope it will be useful, but > + * WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + * General Public License for more details. > + */ > +/* > + * Can be built statically: > + * gcc -Os -Wall -static -m32 test_mremap_vdso.c > + */ > +#define _GNU_SOURCE > +#include > +#include > +#include > +#include > + > +#include > +#include > +#include > + > +#define PAGE_SIZE 4096 > + > +static int try_to_remap(void *vdso_addr, unsigned long size) > +{ > + void *dest_addr, *new_addr; > + > + dest_addr = mmap(0, size, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); > + if (dest_addr == MAP_FAILED) { > + printf("[WARN]\tmmap failed (%d): %m\n", errno); > + return 0; > + } > + > + printf("[NOTE]\tMoving vDSO: [%p, %#lx] -> [%p, %#lx]\n", > + vdso_addr, (unsigned long)vdso_addr + size, > + dest_addr, (unsigned long)dest_addr + size); > + fflush(stdout); > + > + new_addr = mremap(vdso_addr, size, size, > + MREMAP_FIXED|MREMAP_MAYMOVE, dest_addr); > + if ((unsigned long)new_addr == (unsigned long)-1) { > + munmap(dest_addr, size); > + if (errno == EINVAL) { > + printf("[NOTE]\tvDSO partial move failed, will try with bigger size\n"); > + return -1; /* retry with larger */ > + } > + printf("[FAIL]\tmremap failed (%d): %m\n", errno); > + return 1; > + } > + > + return 0; > + > +} > + > +int main(int argc, char **argv, char **envp) > +{ > + unsigned long auxval; > + const char *ok_string = "[OK]\n"; > + int ret = -1; > + unsigned long vdso_size = PAGE_SIZE; > + > + auxval = getauxval(AT_SYSINFO_EHDR); > + printf("\tAT_SYSINFO_EHDR is %#lx\n", auxval); > + if (!auxval || auxval == -ENOENT) { > + printf("[WARN]\tgetauxval failed\n"); > + return 0; > + } > + > + /* simpler than parsing ELF header */ > + while(ret < 0) { > + ret = try_to_remap((void *)auxval, vdso_size); > + vdso_size += PAGE_SIZE; > + } > + > + if (!ret) > +#if defined(__i386__) > + asm volatile ("int $0x80" : : > + "a" (__NR_write), "b" (STDOUT_FILENO), > + "c" (ok_string), "d" (strlen(ok_string))); > + > + asm volatile ("int $0x80" : : "a" (__NR_exit), "b" (!!ret)); > +#else > + asm volatile ("syscall" : : > + "a" (__NR_write), "D" (STDOUT_FILENO), > + "S" (ok_string), "d" (strlen(ok_string))); > + > + asm volatile ("syscall" : : "a" (__NR_exit), "D" (!!ret)); > +#endif > + > + return 0; > +} > -- > 2.8.0 > -- Andy Lutomirski AMA Capital Management, LLC