From: Florian Weimer Date: Mon, 18 May 2020 16:25:18 +0000 (+0200) Subject: nptl: Change type of __default_pthread_attr X-Git-Tag: glibc-2.32~271 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c2322a561f74b8fa41b9d9c6b8eb57e28de46f3e;p=thirdparty%2Fglibc.git nptl: Change type of __default_pthread_attr union pthread_attr_transparent has always the correct size, even if pthread_attr_t has padding that is not present in struct pthread_attr. This should not result in an observable behavioral change. The existing code appears to have been correct, but it was brittle because it was not clear which functions were allowed to write to an entire pthread_attr_t argument (e.g., by copying it). Reviewed-by: Carlos O'Donell --- diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c index c94980c21c8..d16f3d71f81 100644 --- a/nptl/allocatestack.c +++ b/nptl/allocatestack.c @@ -425,7 +425,7 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp, else { lll_lock (__default_pthread_attr_lock, LLL_PRIVATE); - size = __default_pthread_attr.stacksize; + size = __default_pthread_attr.internal.stacksize; lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE); } diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c index 96b1444a01b..d4cf20e3d1b 100644 --- a/nptl/nptl-init.c +++ b/nptl/nptl-init.c @@ -318,8 +318,8 @@ __pthread_initialize_minimal_internal (void) /* Round the resource limit up to page size. */ limit.rlim_cur = ALIGN_UP (limit.rlim_cur, pagesz); lll_lock (__default_pthread_attr_lock, LLL_PRIVATE); - __default_pthread_attr.stacksize = limit.rlim_cur; - __default_pthread_attr.guardsize = GLRO (dl_pagesize); + __default_pthread_attr.internal.stacksize = limit.rlim_cur; + __default_pthread_attr.internal.guardsize = GLRO (dl_pagesize); lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE); #ifdef SHARED diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h index 9c6dd41b7c2..acc8e88e4a2 100644 --- a/nptl/pthreadP.h +++ b/nptl/pthreadP.h @@ -199,7 +199,7 @@ enum /* Default pthread attributes. */ -extern struct pthread_attr __default_pthread_attr attribute_hidden; +extern union pthread_attr_transparent __default_pthread_attr attribute_hidden; extern int __default_pthread_attr_lock attribute_hidden; /* Size and alignment of static TLS block. */ diff --git a/nptl/pthread_attr_getstacksize.c b/nptl/pthread_attr_getstacksize.c index 346b375690d..9830a635a6a 100644 --- a/nptl/pthread_attr_getstacksize.c +++ b/nptl/pthread_attr_getstacksize.c @@ -33,7 +33,7 @@ __pthread_attr_getstacksize (const pthread_attr_t *attr, size_t *stacksize) if (size == 0) { lll_lock (__default_pthread_attr_lock, LLL_PRIVATE); - size = __default_pthread_attr.stacksize; + size = __default_pthread_attr.internal.stacksize; lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE); } *stacksize = size; diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c index 347d5107074..86fbeb52184 100644 --- a/nptl/pthread_create.c +++ b/nptl/pthread_create.c @@ -612,16 +612,16 @@ __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr, STACK_VARIABLES; const struct pthread_attr *iattr = (struct pthread_attr *) attr; - struct pthread_attr default_attr; + union pthread_attr_transparent default_attr; bool destroy_default_attr = false; bool c11 = (attr == ATTR_C11_THREAD); if (iattr == NULL || c11) { - int ret = __pthread_getattr_default_np ((pthread_attr_t *) &default_attr); + int ret = __pthread_getattr_default_np (&default_attr.external); if (ret != 0) return ret; destroy_default_attr = true; - iattr = &default_attr; + iattr = &default_attr.internal; } struct pthread *pd = NULL; @@ -852,7 +852,7 @@ __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr, out: if (destroy_default_attr) - __pthread_attr_destroy ((pthread_attr_t *) &default_attr); + __pthread_attr_destroy (&default_attr.external); return retval; } diff --git a/nptl/pthread_getattr_default_np.c b/nptl/pthread_getattr_default_np.c index 5c99f980e21..f3ce1c2885a 100644 --- a/nptl/pthread_getattr_default_np.c +++ b/nptl/pthread_getattr_default_np.c @@ -22,8 +22,7 @@ int __pthread_getattr_default_np (pthread_attr_t *out) { lll_lock (__default_pthread_attr_lock, LLL_PRIVATE); - int ret = __pthread_attr_copy (out, - (pthread_attr_t *) &__default_pthread_attr); + int ret = __pthread_attr_copy (out, &__default_pthread_attr.external); lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE); return ret; } diff --git a/nptl/pthread_setattr_default_np.c b/nptl/pthread_setattr_default_np.c index eb5d24d3bde..c4cfb4e8efa 100644 --- a/nptl/pthread_setattr_default_np.c +++ b/nptl/pthread_setattr_default_np.c @@ -68,15 +68,15 @@ pthread_setattr_default_np (const pthread_attr_t *in) /* Preserve the previous stack size (see above). */ if (temp.internal.stacksize == 0) - temp.internal.stacksize = __default_pthread_attr.stacksize; + temp.internal.stacksize = __default_pthread_attr.internal.stacksize; /* Destroy the old attribute structure because it will be overwritten. */ - __pthread_attr_destroy ((pthread_attr_t *) &__default_pthread_attr); + __pthread_attr_destroy (&__default_pthread_attr.external); /* __default_pthread_attr takes ownership, so do not free attrs.internal after this point. */ - __default_pthread_attr = temp.internal; + __default_pthread_attr = temp; lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE); return ret; diff --git a/nptl/vars.c b/nptl/vars.c index b88300d9b48..36960201450 100644 --- a/nptl/vars.c +++ b/nptl/vars.c @@ -22,7 +22,7 @@ /* Default thread attributes for the case when the user does not provide any. */ -struct pthread_attr __default_pthread_attr attribute_hidden; +union pthread_attr_transparent __default_pthread_attr attribute_hidden; /* Mutex protecting __default_pthread_attr. */ int __default_pthread_attr_lock = LLL_LOCK_INITIALIZER;