From 92a7d1343991897f77afe01041f3b77712445e47 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Sun, 23 May 2021 10:25:10 -0700 Subject: x86-64: Align child stack to 16 bytes [BZ #27902] In the x86-64 clone wrapper, align child stack to 16 bytes per the x86-64 psABI. Reviewed-by: Carlos O'Donell --- sysdeps/unix/sysv/linux/Makefile | 2 +- sysdeps/unix/sysv/linux/tst-misalign-clone.c | 96 ++++++++++++++++++++++++++++ sysdeps/unix/sysv/linux/x86_64/clone.S | 9 ++- 3 files changed, 103 insertions(+), 4 deletions(-) create mode 100644 sysdeps/unix/sysv/linux/tst-misalign-clone.c (limited to 'sysdeps') diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile index e9566e028a..bc14f20274 100644 --- a/sysdeps/unix/sysv/linux/Makefile +++ b/sysdeps/unix/sysv/linux/Makefile @@ -109,7 +109,7 @@ tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \ tst-tgkill tst-sysvsem-linux tst-sysvmsg-linux tst-sysvshm-linux \ tst-timerfd tst-ppoll \ tst-clock_adjtime tst-adjtimex tst-ntp_adjtime tst-ntp_gettime \ - tst-ntp_gettimex tst-sigtimedwait + tst-ntp_gettimex tst-sigtimedwait tst-misalign-clone # Test for the symbol version of fcntl that was replaced in glibc 2.28. ifeq ($(have-GLIBC_2.27)$(build-shared),yesyes) diff --git a/sysdeps/unix/sysv/linux/tst-misalign-clone.c b/sysdeps/unix/sysv/linux/tst-misalign-clone.c new file mode 100644 index 0000000000..60f0ed0839 --- /dev/null +++ b/sysdeps/unix/sysv/linux/tst-misalign-clone.c @@ -0,0 +1,96 @@ +/* Verify that the clone wrapper properly aligns the child stack. + Copyright (C) 2021 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static int +check_stack_alignment (void *arg) +{ + bool ok = true; + + puts ("in f"); + + if (TEST_STACK_ALIGN ()) + ok = false; + + return ok ? 0 : 1; +} + +static int +do_test (void) +{ + puts ("in do_test"); + + if (TEST_STACK_ALIGN ()) + FAIL_EXIT1 ("stack isn't aligned\n"); + +#ifdef __ia64__ +# define STACK_SIZE (256 * 1024) +#else +# define STACK_SIZE (128 * 1024) +#endif + + char st[STACK_SIZE + 1]; + /* NB: Align child stack to 1 byte. */ + char *stack = PTR_ALIGN_UP (&st[0], 2) + 1; + +#ifdef __ia64__ + extern int __clone2 (int (*__fn) (void *__arg), void *__child_stack_base, + size_t __child_stack_size, int __flags, + void *__arg, ...); + pid_t p = __clone2 (check_stack_alignment, stack, STACK_SIZE, 0, 0); +#else +# if _STACK_GROWS_DOWN + pid_t p = clone (check_stack_alignment, stack + STACK_SIZE, 0, 0); +# elif _STACK_GROWS_UP + pid_t p = clone (check_stack_alignment, stack, 0, 0); +# else +# error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP" +# endif +#endif + + /* Clone must not fail. */ + TEST_VERIFY_EXIT (p != -1); + + int e; + xwaitpid (p, &e, __WCLONE); + if (!WIFEXITED (e)) + { + if (WIFSIGNALED (e)) + printf ("died from signal %s\n", strsignal (WTERMSIG (e))); + FAIL_EXIT1 ("process did not terminate correctly"); + } + + if (WEXITSTATUS (e) != 0) + FAIL_EXIT1 ("exit code %d", WEXITSTATUS (e)); + + return 0; +} + +#include diff --git a/sysdeps/unix/sysv/linux/x86_64/clone.S b/sysdeps/unix/sysv/linux/x86_64/clone.S index 31ac12da0c..7418154c4b 100644 --- a/sysdeps/unix/sysv/linux/x86_64/clone.S +++ b/sysdeps/unix/sysv/linux/x86_64/clone.S @@ -54,12 +54,15 @@ ENTRY (__clone) movq $-EINVAL,%rax testq %rdi,%rdi /* no NULL function pointers */ jz SYSCALL_ERROR_LABEL - testq %rsi,%rsi /* no NULL stack pointers */ - jz SYSCALL_ERROR_LABEL + + /* Align stack to 16 bytes per the x86-64 psABI. */ + andq $-16, %rsi + jz SYSCALL_ERROR_LABEL /* no NULL stack pointers */ /* Insert the argument onto the new stack. */ + movq %rcx,-8(%rsi) + subq $16,%rsi - movq %rcx,8(%rsi) /* Save the function pointer. It will be popped off in the child. */ -- cgit 1.4.1