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Pull up following revision(s) (requested by riastradh in ticket #1924): 

tests/lib/libpthread/Makefile: revision 1.16
	lib/libpthread/pthread.c: revision 1.184
	distrib/sets/lists/debug/mi: revision 1.424
	distrib/sets/lists/tests/mi: revision 1.1297
	tests/lib/libpthread/t_stack.c: revision 1.1
	tests/lib/libpthread/t_stack.c: revision 1.2
	tests/lib/libpthread/t_stack.c: revision 1.3
	tests/lib/libpthread/t_stack.c: revision 1.4
	tests/lib/libpthread/t_stack.c: revision 1.5
	tests/lib/libpthread/t_stack.c: revision 1.6

pthread: Add tests for pthread user stack allocation.
PR lib/57721

libpthread/t_stack: Make this more robust to the guard size bug.
Make sure to allocate enough space for the thread's stack for a guard
even though there shouldn't be one, so that when we run the thread,
it doesn't start with the stack pointer pointing into someone else's
allocation (like malloc) causing stack frames to trash another data
structure -- or causing the user of that data structure to trash the
stack frames.
PR lib/57721

libpthread/t_stack: Omit needless cast in previous.
Arose from an earlier draft of the change.
PR lib/57721

libpthread/t_stack: Appease gcc12 maybe-uninitialized warning.
The jmp_buf is not, in fact, uninitialized at the point of use, but
it doesn't hurt to narrow the scope a bit to between when the jmp_buf
is initialized by setjmp, and when the signal handler might be called
after sigaction.
Noted by prlw1.
PR lib/57721

libpthread/t_stack: Fix format string for size_t.
Tested this on i386 since that had been crashing before, but i386
doesn't see %zu for unsigned int as a problem.
PR lib/57721

pthread: Don't adjust user-allocated stack addresses by guardsize.
PR lib/57721
This commit is contained in:
martin 2023-12-09 13:36:02 +00:00
parent b5e98a79d9
commit 31521c7e79
5 changed files with 503 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
distrib/sets/lists/debug/mi
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@ -1,4 +1,4 @@
# $NetBSD: mi,v 1.216.2.10 2023/08/09 16:16:40 martin Exp $
# $NetBSD: mi,v 1.216.2.11 2023/12/09 13:36:03 martin Exp $
./etc/mtree/set.debug comp-sys-root
./usr/lib comp-sys-usr compatdir
./usr/lib/i18n/libBIG5_g.a comp-c-debuglib debuglib,compatfile
@ -2219,6 +2219,7 @@
./usr/libdata/debug/usr/tests/lib/libpthread/t_sigmask.debug tests-lib-tests debug,atf,compattestfile
./usr/libdata/debug/usr/tests/lib/libpthread/t_sigsuspend.debug tests-lib-tests debug,atf,compattestfile
./usr/libdata/debug/usr/tests/lib/libpthread/t_sleep.debug tests-lib-tests debug,atf,compattestfile
./usr/libdata/debug/usr/tests/lib/libpthread/t_stack.debug tests-lib-tests debug,atf,compattestfile
./usr/libdata/debug/usr/tests/lib/libpthread/t_status.debug tests-obsolete obsolete,compattestfile
./usr/libdata/debug/usr/tests/lib/libpthread/t_swapcontext.debug tests-lib-tests debug,atf,compattestfile
./usr/libdata/debug/usr/tests/lib/libpthread/t_timedmutex.debug tests-lib-tests debug,atf,compattestfile

3
distrib/sets/lists/tests/mi
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@ -1,4 +1,4 @@
# $NetBSD: mi,v 1.752.2.11 2023/08/09 16:16:40 martin Exp $
# $NetBSD: mi,v 1.752.2.12 2023/12/09 13:36:03 martin Exp $
#
# Note: don't delete entries from here - mark them as "obsolete" instead.
#
@ -3070,6 +3070,7 @@
./usr/tests/lib/libpthread/t_sigmask tests-lib-tests compattestfile,atf
./usr/tests/lib/libpthread/t_sigsuspend tests-lib-tests compattestfile,atf
./usr/tests/lib/libpthread/t_sleep tests-lib-tests compattestfile,atf
./usr/tests/lib/libpthread/t_stack tests-lib-tests compattestfile,atf
./usr/tests/lib/libpthread/t_status tests-obsolete obsolete
./usr/tests/lib/libpthread/t_swapcontext tests-lib-tests compattestfile,atf
./usr/tests/lib/libpthread/t_thread_local_dtor tests-lib-tests compattestfile,atf

9
lib/libpthread/pthread.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: pthread.c,v 1.147.8.3 2017/08/31 08:32:39 bouyer Exp $ */
/* $NetBSD: pthread.c,v 1.147.8.4 2023/12/09 13:36:03 martin Exp $ */
/*-
* Copyright (c) 2001, 2002, 2003, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: pthread.c,v 1.147.8.3 2017/08/31 08:32:39 bouyer Exp $");
__RCSID("$NetBSD: pthread.c,v 1.147.8.4 2023/12/09 13:36:03 martin Exp $");
#define __EXPOSE_STACK 1
@ -350,7 +350,10 @@ pthread__getstack(pthread_t newthread, const pthread_attr_t *attr)
if (attr != NULL) {
pthread_attr_getstack(attr, &stackbase, &stacksize);
pthread_attr_getguardsize(attr, &guardsize);
if (stackbase == NULL)
pthread_attr_getguardsize(attr, &guardsize);
else
guardsize = 0;
} else {
stackbase = NULL;
stacksize = 0;

3
tests/lib/libpthread/Makefile
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@ -1,4 +1,4 @@
# $NetBSD: Makefile,v 1.12.6.1 2017/08/29 09:43:18 bouyer Exp $
# $NetBSD: Makefile,v 1.12.6.2 2023/12/09 13:36:02 martin Exp $
NOMAN= # defined
@ -37,6 +37,7 @@ TESTS_C+= t_sigmask
TESTS_C+= t_sigsuspend
TESTS_C+= t_siglongjmp
TESTS_C+= t_sleep
TESTS_C+= t_stack
TESTS_C+= t_swapcontext
TESTS_SH+= t_thread_local_dtor
TESTS_C+= t_timedmutex

491
tests/lib/libpthread/t_stack.c Normal file
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@ -0,0 +1,491 @@
/* $NetBSD: t_stack.c,v 1.6.6.2 2023/12/09 13:36:02 martin Exp $ */
/*-
* Copyright (c) 2023 The NetBSD Foundation, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#define _KMEMUSER /* __MACHINE_STACK_GROWS_UP */
#include <sys/cdefs.h>
__RCSID("$NetBSD: t_stack.c,v 1.6.6.2 2023/12/09 13:36:02 martin Exp $");
#include <sys/mman.h>
#include <sys/param.h>
#include <sys/sysctl.h>
#include <sys/types.h>
#include <uvm/uvm_param.h> /* VM_THREAD_GUARD_SIZE */
#include <atf-c.h>
#include <pthread.h>
#include <setjmp.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#include "h_macros.h"
struct jmp_ctx {
jmp_buf buf;
};
/*
* State used by various tests.
*/
struct ctx {
size_t size; /* default stack size */
size_t guardsize; /* default guard size */
void *addr; /* user-allocated stack */
pthread_key_t jmp_key; /* jmp_ctx to return from SIGSEGV handler */
} ctx, *C = &ctx;
/*
* getdefaultstacksize()
*
* Return the default stack size for threads created with
* pthread_create.
*/
static size_t
getdefaultstacksize(void)
{
pthread_attr_t attr;
size_t stacksize;
/*
* When called from the main thread, this returns the default
* stack size (pthread__stacksize) used for pthreads.
*/
RZ(pthread_getattr_np(pthread_self(), &attr));
RZ(pthread_attr_getstacksize(&attr, &stacksize));
RZ(pthread_attr_destroy(&attr));
/*
* Verify that the assumption above holds.
*/
extern size_t pthread__stacksize; /* pthread_int.h */
ATF_CHECK_EQ_MSG(stacksize, pthread__stacksize,
"stacksize=%zu pthread__stacksize=%zu",
stacksize, pthread__stacksize);
return stacksize;
}
/*
* getnondefaultstacksize()
*
* Return a stack size that is not the default stack size for
* threads created with pthread_create.
*/
static size_t
getnondefaultstacksize(void)
{
return getdefaultstacksize() + sysconf(_SC_PAGESIZE);
}
/*
* getdefaultguardsize()
*
* Return the default guard size for threads created with
* pthread_create.
*/
static size_t
getdefaultguardsize(void)
{
const int mib[2] = { CTL_VM, VM_THREAD_GUARD_SIZE };
unsigned guardsize;
size_t len = sizeof(guardsize);
RL(sysctl(mib, __arraycount(mib), &guardsize, &len, NULL, 0));
ATF_REQUIRE_EQ_MSG(len, sizeof(guardsize),
"len=%zu sizeof(guardsize)=%zu", len, sizeof(guardsize));
/*
* Verify this matches what libpthread determined.
*/
extern size_t pthread__guardsize; /* pthread_int.h */
ATF_CHECK_EQ_MSG(guardsize, pthread__guardsize,
"guardsize=%u pthread__guardsize=%zu",
guardsize, pthread__guardsize);
return guardsize;
}
/*
* alloc(nbytes)
*
* Allocate an nbytes-long page-aligned read/write region and
* return a pointer to it. Abort the test if allocation fails, so
* if this function returns it succeeds.
*/
static void *
alloc(size_t nbytes)
{
void *ptr;
REQUIRE_LIBC((ptr = mmap(/*hint*/NULL, nbytes,
PROT_READ|PROT_WRITE, MAP_ANON, /*fd*/-1, /*offset*/0)),
MAP_FAILED);
return ptr;
}
/*
* init(stacksize)
*
* Initialize state used by various tests with the specified
* stacksize.
*
* Make sure to allocate enough space that even if there shouldn't
* be a stack guard (i.e., it should be empty), adjusting the
* requested bounds by the default stack guard size will leave us
* inside allocated memory.
*/
static void
init(size_t stacksize)
{
C->size = stacksize;
C->guardsize = getdefaultguardsize();
C->addr = alloc(C->size + C->guardsize);
RZ(pthread_key_create(&C->jmp_key, NULL));
}
/*
* stack_pointer()
*
* Return the stack pointer. This is used to verify whether the
* stack pointer lie within a certain address range.
*/
static __noinline void *
stack_pointer(void)
{
return __builtin_frame_address(0);
}
/*
* sigsegv_ok(signo)
*
* Signal handler for SIGSEGV to return to the jmp ctx, to verify
* that SIGSEGV happened without crashing.
*/
static void
sigsegv_ok(int signo)
{
struct jmp_ctx *j = pthread_getspecific(C->jmp_key);
longjmp(j->buf, 1);
}
/*
* checksigsegv(p)
*
* Verify that reading *p triggers SIGSEGV. Fails test nonfatally
* if SIGSEGV doesn't happen.
*/
static void
checksigsegv(const char *p)
{
struct jmp_ctx j;
struct sigaction act, oact;
volatile struct sigaction oactsave;
volatile char v;
memset(&act, 0, sizeof(act));
act.sa_handler = &sigsegv_ok;
if (setjmp(j.buf) == 0) {
pthread_setspecific(C->jmp_key, &j);
RL(sigaction(SIGSEGV, &act, &oact));
oactsave = oact;
v = *p; /* trigger SIGSEGV */
atf_tc_fail_nonfatal("failed to trigger SIGSEGV at %p", p);
} else {
/* return from SIGSEGV handler */
oact = oactsave;
}
RL(sigaction(SIGSEGV, &oact, NULL));
pthread_setspecific(C->jmp_key, NULL);
(void)v; /* suppress unused variable warnings */
}
/*
* checknosigsegv(p)
*
* Verify that reading *p does not trigger SIGSEGV. Fails test
* nonfatally if SIGSEGV happens.
*/
static void
checknosigsegv(const char *p)
{
struct jmp_ctx j;
struct sigaction act, oact;
volatile struct sigaction oactsave;
volatile char v;
memset(&act, 0, sizeof(act));
act.sa_handler = &sigsegv_ok;
if (setjmp(j.buf) == 0) {
pthread_setspecific(C->jmp_key, &j);
RL(sigaction(SIGSEGV, &act, &oact));
oactsave = oact;
v = *p; /* better not trigger SIGSEGV */
} else {
/* return from SIGSEGV handler */
atf_tc_fail_nonfatal("spuriously triggered SIGSEGV at %p", p);
oact = oactsave;
}
RL(sigaction(SIGSEGV, &oact, NULL));
pthread_setspecific(C->jmp_key, NULL);
(void)v; /* suppress unused variable warnings */
}
/*
* checkguardaccessthread(cookie)
*
* Thread start routine that verifies it has access to the start
* and end of its stack, according to pthread_attr_getstack, and
* _does not_ have access to the start or end of its stack guard,
* above the stack (in stack growth direction) by
* pthread_attr_getguardsize bytes.
*/
static void *
checkguardaccessthread(void *cookie)
{
pthread_t t = pthread_self();
pthread_attr_t attr;
void *addr, *guard;
size_t size, guardsize;
/*
* Get the the stack and stack guard parameters.
*/
RZ(pthread_getattr_np(t, &attr));
RZ(pthread_attr_getstack(&attr, &addr, &size));
RZ(pthread_attr_getguardsize(&attr, &guardsize));
/*
* Determine where the guard starts in virtual address space
* (not in stack growth direction).
*/
#ifdef __MACHINE_STACK_GROWS_UP
guard = (char *)addr + size;
#else
guard = (char *)addr - guardsize;
#endif
/*
* Verify access to the start and end of the stack itself.
*/
checknosigsegv(addr);
checknosigsegv((char *)addr + size - 1);
/*
* Verify no access to the start or end of the stack guard.
*/
checksigsegv(guard);
checksigsegv((char *)guard + guardsize - 1);
return NULL;
}
/*
* checkaddraccessthread(cookie)
*
* Thread start routine that verifies its stack is [C->addr,
* C->addr + C->size), according to pthread_attr_getstack and
* pthread_addr_getstacksize, and verifies it has access to that
* whole range.
*/
static void *
checkaddraccessthread(void *cookie)
{
pthread_t t = pthread_self();
pthread_attr_t attr;
void *sp;
void *addr;
size_t size, size0;
/*
* Verify the stack pointer lies somewhere in the allocated
* range.
*/
sp = stack_pointer();
ATF_CHECK_MSG(C->addr <= sp, "sp=%p not in [%p,%p + 0x%zu) = [%p,%p)",
sp, C->addr, C->addr, C->size, C->addr, (char *)C->addr + C->size);
ATF_CHECK_MSG(sp <= (void *)((char *)C->addr + C->size),
"sp=%p not in [%p,%p + 0x%zu) = [%p,%p)",
sp, C->addr, C->addr, C->size, C->addr, (char *)C->addr + C->size);
/*
* Verify, if not that, then the stack pointer at least lies
* within the extra buffer we allocated for slop to address a
* bug NetBSD libpthread used to have of spuriously adding the
* guard size to a user-allocated stack address. This is
* ATF_REQUIRE, not ATF_CHECK, because if this doesn't hold, we
* might be clobbering some other memory like malloc pages,
* causing the whole test to crash with useless diagnostics.
*/
ATF_REQUIRE_MSG(sp <= (void *)((char *)C->addr + C->size +
C->guardsize),
"sp=%p not even in buffer [%p,%p + 0x%zu + 0x%zu) = [%p,%p)",
sp, C->addr, C->addr, C->size, C->guardsize,
C->addr, (char *)C->addr + C->size + C->guardsize);
/*
* Get the stack parameters -- both via pthread_attr_getstack
* and via pthread_attr_getstacksize, to make sure they agree
* -- and verify that they are what we expect from the caller.
*/
RZ(pthread_getattr_np(t, &attr));
RZ(pthread_attr_getstack(&attr, &addr, &size));
RZ(pthread_attr_getstacksize(&attr, &size0));
ATF_CHECK_EQ_MSG(C->addr, addr, "expected %p actual %p",
C->addr, addr);
ATF_CHECK_EQ_MSG(C->size, size, "expected %zu actual %zu",
C->size, size);
ATF_CHECK_EQ_MSG(C->size, size0, "expected %zu actual %zu",
C->size, size0);
/*
* Verify that we have access to what we expect the stack to
* be.
*/
checknosigsegv(C->addr);
checknosigsegv((char *)C->addr + C->size - 1);
return NULL;
}
ATF_TC(stack1);
ATF_TC_HEAD(stack1, tc)
{
atf_tc_set_md_var(tc, "descr",
"Test allocating and reallocating a thread with a user stack");
}
ATF_TC_BODY(stack1, tc)
{
pthread_attr_t attr;
pthread_t t, t2;
/*
* Allocate a stack with a non-default size to verify
* libpthread didn't choose the stack size for us.
*/
init(getnondefaultstacksize());
/*
* Create a thread with user-allocated stack of a non-default
* size to verify the stack size and access.
*/
RZ(pthread_attr_init(&attr));
RZ(pthread_attr_setstack(&attr, C->addr, C->size));
RZ(pthread_create(&t, &attr, &checkaddraccessthread, C));
RZ(pthread_join(t, NULL));
/*
* Create another thread with the same parameters, and verify
* that (a) it was recycled, and (b) it works the same way.
*/
RZ(pthread_create(&t2, &attr, &checkaddraccessthread, C));
ATF_CHECK_EQ_MSG(t, t2, "t=%p t2=%p", t, t2); /* NetBSD recycles */
RZ(pthread_join(t2, NULL));
}
ATF_TC(stack2);
ATF_TC_HEAD(stack2, tc)
{
atf_tc_set_md_var(tc, "descr",
"Test reallocating a thread with a newly self-allocated stack");
}
ATF_TC_BODY(stack2, tc)
{
pthread_attr_t attr, attr2;
size_t size, size2;
pthread_t t, t2;
/*
* Allocate a stack with the default size so that we verify
* when libpthread reuses the thread, it doesn't inadvertently
* reuse the libpthread-allocated stack too and instead
* correctly uses our user-allocated stack.
*/
init(getdefaultstacksize());
/*
* Create a thread with a libpthread-allocated stack that
* verifies
* (a) access to its own stack, and
* (b) no access to its own guard pages;
* then get its attributes and wait for it to complete.
*/
RZ(pthread_create(&t, NULL, &checkguardaccessthread, C));
RZ(pthread_getattr_np(t, &attr));
RZ(pthread_join(t, NULL));
/*
* Create a thread with a user-allocated stack that verifies
* (a) stack addr/size match request, and
* (b) access to the requested stack,
* and confirm that the first thread was recycled -- not part
* of POSIX semantics, but part of NetBSD's implementation;
* this way, we verify that, even though the thread is
* recycled, the thread's stack is set to the user-allocated
* stack and access to it works as expected. Then wait for it
* to complete.
*/
RZ(pthread_attr_init(&attr2));
RZ(pthread_attr_setstack(&attr2, C->addr, C->size));
RZ(pthread_create(&t2, &attr2, &checkaddraccessthread, C));
ATF_CHECK_EQ_MSG(t, t2, "t=%p t2=%p", t, t2); /* NetBSD recycles */
RZ(pthread_join(t2, NULL));
/*
* Verify that the libpthread-allocated stack and
* user-allocated stack had the same size, since we chose the
* default size.
*
* Note: We can't say anything about the guard size, because
* with pthread_attr_setstack, the guard size is ignored, and
* it's not clear from POSIX whether any meaningful guard size
* is stored for retrieval with pthread_attr_getguardsize in
* attributes with pthread_attr_setstack.
*/
RZ(pthread_attr_getstacksize(&attr, &size));
RZ(pthread_attr_getstacksize(&attr2, &size2));
ATF_CHECK_EQ_MSG(size, size2, "size=%zu size2=%zu", size, size2);
}
ATF_TP_ADD_TCS(tp)
{
ATF_TP_ADD_TC(tp, stack1);
ATF_TP_ADD_TC(tp, stack2);
return atf_no_error();
}