Date: Fri, 16 Sep 2022 20:25:43 GMT
From: Konstantin Belousov <kib@FreeBSD.org>
To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org
Subject: git: e2879ece4314 - main - libc, libthr: use AT_USRSTACK{BASE,LIM} instead of sysctl("kern.usrstack") and get_rlimit(RLIMIT_STACK)
Message-ID: <202209162025.28GKPhmk026462@gitrepo.freebsd.org>
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The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=e2879ece4314eed2d22fe484bd4adfcbb1009685 commit e2879ece4314eed2d22fe484bd4adfcbb1009685 Author: Konstantin Belousov <kib@FreeBSD.org> AuthorDate: 2022-09-12 19:45:21 +0000 Commit: Konstantin Belousov <kib@FreeBSD.org> CommitDate: 2022-09-16 20:24:06 +0000 libc, libthr: use AT_USRSTACK{BASE,LIM} instead of sysctl("kern.usrstack") and get_rlimit(RLIMIT_STACK) Reviewed by: brooks, imp (previous version) Discussed with: markj Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Differential revision: https://reviews.freebsd.org/D36540 --- lib/libc/gen/elf_utils.c | 27 ++++++++++++++++----------- lib/libthr/thread/thr_init.c | 25 +++++++++++++++++-------- lib/libthr/thread/thr_stack.c | 26 ++++++++++++++++---------- 3 files changed, 49 insertions(+), 29 deletions(-) diff --git a/lib/libc/gen/elf_utils.c b/lib/libc/gen/elf_utils.c index ea5cc25f8601..ed3ac843f7c3 100644 --- a/lib/libc/gen/elf_utils.c +++ b/lib/libc/gen/elf_utils.c @@ -29,6 +29,7 @@ */ #include <sys/param.h> +#include <sys/auxv.h> #include <sys/mman.h> #include <sys/resource.h> #include <sys/sysctl.h> @@ -77,19 +78,23 @@ __libc_map_stacks_exec(void) { int mib[2]; struct rlimit rlim; - u_long usrstack; + u_long usrstack, stacksz; size_t len; - mib[0] = CTL_KERN; - mib[1] = KERN_USRSTACK; - len = sizeof(usrstack); - if (sysctl(mib, nitems(mib), &usrstack, &len, NULL, 0) - == -1) - return; - if (getrlimit(RLIMIT_STACK, &rlim) == -1) - return; - mprotect((void *)(uintptr_t)(usrstack - rlim.rlim_cur), - rlim.rlim_cur, _rtld_get_stack_prot()); + if (_elf_aux_info(AT_USRSTACKBASE, &usrstack, sizeof(usrstack)) != 0) { + mib[0] = CTL_KERN; + mib[1] = KERN_USRSTACK; + len = sizeof(usrstack); + if (sysctl(mib, nitems(mib), &usrstack, &len, NULL, 0) == -1) + return; + } + if (_elf_aux_info(AT_USRSTACKLIM, &stacksz, sizeof(stacksz)) != 0) { + if (getrlimit(RLIMIT_STACK, &rlim) == -1) + return; + stacksz = rlim.rlim_cur; + } + mprotect((void *)(uintptr_t)(usrstack - stacksz), stacksz, + _rtld_get_stack_prot()); } #pragma weak __pthread_map_stacks_exec diff --git a/lib/libthr/thread/thr_init.c b/lib/libthr/thread/thr_init.c index 0ab051e57994..b9d3265a05dc 100644 --- a/lib/libthr/thread/thr_init.c +++ b/lib/libthr/thread/thr_init.c @@ -38,6 +38,7 @@ __FBSDID("$FreeBSD$"); #include "namespace.h" #include <sys/param.h> +#include <sys/auxv.h> #include <sys/signalvar.h> #include <sys/ioctl.h> #include <sys/link_elf.h> @@ -462,18 +463,26 @@ init_private(void) if (init_once == 0) { __thr_pshared_init(); __thr_malloc_init(); + /* Find the stack top */ - mib[0] = CTL_KERN; - mib[1] = KERN_USRSTACK; - len = sizeof (_usrstack); - if (sysctl(mib, nitems(mib), &_usrstack, &len, NULL, 0) == -1) - PANIC("Cannot get kern.usrstack from sysctl"); + if (elf_aux_info(AT_USRSTACKBASE, &_usrstack, + sizeof(_usrstack)) != 0) { + mib[0] = CTL_KERN; + mib[1] = KERN_USRSTACK; + len = sizeof (_usrstack); + if (sysctl(mib, nitems(mib), &_usrstack, &len, + NULL, 0) == -1) + PANIC("Cannot get kern.usrstack from sysctl"); + } env_bigstack = getenv("LIBPTHREAD_BIGSTACK_MAIN"); env_splitstack = getenv("LIBPTHREAD_SPLITSTACK_MAIN"); if (env_bigstack != NULL || env_splitstack == NULL) { - if (getrlimit(RLIMIT_STACK, &rlim) == -1) - PANIC("Cannot get stack rlimit"); - _thr_stack_initial = rlim.rlim_cur; + if (elf_aux_info(AT_USRSTACKLIM, &_thr_stack_initial, + sizeof(_thr_stack_initial)) != 0) { + if (getrlimit(RLIMIT_STACK, &rlim) == -1) + PANIC("Cannot get stack rlimit"); + _thr_stack_initial = rlim.rlim_cur; + } } _thr_is_smp = sysconf(_SC_NPROCESSORS_CONF); if (_thr_is_smp == -1) diff --git a/lib/libthr/thread/thr_stack.c b/lib/libthr/thread/thr_stack.c index af396fe2ba93..34536ecfad2e 100644 --- a/lib/libthr/thread/thr_stack.c +++ b/lib/libthr/thread/thr_stack.c @@ -31,6 +31,7 @@ __FBSDID("$FreeBSD$"); #include <sys/param.h> +#include <sys/auxv.h> #include <sys/mman.h> #include <sys/queue.h> #include <sys/resource.h> @@ -149,18 +150,23 @@ singlethread_map_stacks_exec(void) { int mib[2]; struct rlimit rlim; - u_long usrstack; + u_long usrstack, stacksz; size_t len; - mib[0] = CTL_KERN; - mib[1] = KERN_USRSTACK; - len = sizeof(usrstack); - if (sysctl(mib, nitems(mib), &usrstack, &len, NULL, 0) == -1) - return; - if (getrlimit(RLIMIT_STACK, &rlim) == -1) - return; - mprotect((void *)(uintptr_t)(usrstack - rlim.rlim_cur), - rlim.rlim_cur, _rtld_get_stack_prot()); + if (elf_aux_info(AT_USRSTACKBASE, &usrstack, sizeof(usrstack)) != 0) { + mib[0] = CTL_KERN; + mib[1] = KERN_USRSTACK; + len = sizeof(usrstack); + if (sysctl(mib, nitems(mib), &usrstack, &len, NULL, 0) == -1) + return; + } + if (elf_aux_info(AT_USRSTACKLIM, &stacksz, sizeof(stacksz)) != 0) { + if (getrlimit(RLIMIT_STACK, &rlim) == -1) + return; + stacksz = rlim.rlim_cur; + } + mprotect((void *)(uintptr_t)(usrstack - stacksz), stacksz, + _rtld_get_stack_prot()); } void
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