GNU C Library master sources branch master updated. glibc-2.26.9000-1097-g630f4cc

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http://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=630f4cc3aa019ede55976ea561f1a7af2f068639

commit 630f4cc3aa019ede55976ea561f1a7af2f068639
Author: Szabolcs Nagy <szabolcs.nagy@arm.com>
Date:   Wed Dec 6 13:05:50 2017 +0000

    [BZ #22637] Fix stack guard size accounting
    
    Previously if user requested S stack and G guard when creating a
    thread, the total mapping was S and the actual available stack was
    S - G - static_tls, which is not what the user requested.
    
    This patch fixes the guard size accounting by pretending the user
    requested S+G stack.  This way all later logic works out except
    when reporting the user requested stack size (pthread_getattr_np)
    or when computing the minimal stack size (__pthread_get_minstack).
    
    Normally this will increase thread stack allocations by one page.
    TLS accounting is not affected, that will require a separate fix.
    
    	[BZ #22637]
    	* nptl/descr.h (stackblock, stackblock_size): Update comments.
    	* nptl/allocatestack.c (allocate_stack): Add guardsize to stacksize.
    	* nptl/nptl-init.c (__pthread_get_minstack): Remove guardsize from
    	stacksize.
    	* nptl/pthread_getattr_np.c (pthread_getattr_np): Likewise.

diff --git a/ChangeLog b/ChangeLog
index ad0641e..8824881 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2018-01-08  Szabolcs Nagy  <szabolcs.nagy@arm.com>
+
+	[BZ #22637]
+	* nptl/descr.h (stackblock, stackblock_size): Update comments.
+	* nptl/allocatestack.c (allocate_stack): Add guardsize to stacksize.
+	* nptl/nptl-init.c (__pthread_get_minstack): Remove guardsize from
+	stacksize.
+	* nptl/pthread_getattr_np.c (pthread_getattr_np): Likewise.
+
 2018-01-08  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* sysdeps/x86_64/fpu/multiarch/Makefile (libm-sysdep_routines):
diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c
index 05b8ed3..b374f47 100644
--- a/nptl/allocatestack.c
+++ b/nptl/allocatestack.c
@@ -532,6 +532,10 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp,
       /* Make sure the size of the stack is enough for the guard and
 	 eventually the thread descriptor.  */
       guardsize = (attr->guardsize + pagesize_m1) & ~pagesize_m1;
+      if (guardsize < attr->guardsize || size + guardsize < guardsize)
+	/* Arithmetic overflow.  */
+	return EINVAL;
+      size += guardsize;
       if (__builtin_expect (size < ((guardsize + __static_tls_size
 				     + MINIMAL_REST_STACK + pagesize_m1)
 				    & ~pagesize_m1),
diff --git a/nptl/descr.h b/nptl/descr.h
index da9c567..1cc6b09 100644
--- a/nptl/descr.h
+++ b/nptl/descr.h
@@ -383,9 +383,9 @@ struct pthread
   /* Machine-specific unwind info.  */
   struct _Unwind_Exception exc;
 
-  /* If nonzero pointer to area allocated for the stack and its
-     size.  */
+  /* If nonzero, pointer to the area allocated for the stack and guard. */
   void *stackblock;
+  /* Size of the stackblock area including the guard.  */
   size_t stackblock_size;
   /* Size of the included guard area.  */
   size_t guardsize;
diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c
index c237a36..5a4b524 100644
--- a/nptl/nptl-init.c
+++ b/nptl/nptl-init.c
@@ -472,8 +472,5 @@ strong_alias (__pthread_initialize_minimal_internal,
 size_t
 __pthread_get_minstack (const pthread_attr_t *attr)
 {
-  struct pthread_attr *iattr = (struct pthread_attr *) attr;
-
-  return (GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN
-	  + iattr->guardsize);
+  return GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN;
 }
diff --git a/nptl/pthread_getattr_np.c b/nptl/pthread_getattr_np.c
index 961d711..ae12592 100644
--- a/nptl/pthread_getattr_np.c
+++ b/nptl/pthread_getattr_np.c
@@ -57,9 +57,12 @@ pthread_getattr_np (pthread_t thread_id, pthread_attr_t *attr)
   /* The sizes are subject to alignment.  */
   if (__glibc_likely (thread->stackblock != NULL))
     {
-      iattr->stacksize = thread->stackblock_size;
+      /* The stack size reported to the user should not include the
+	 guard size.  */
+      iattr->stacksize = thread->stackblock_size - thread->guardsize;
 #if _STACK_GROWS_DOWN
-      iattr->stackaddr = (char *) thread->stackblock + iattr->stacksize;
+      iattr->stackaddr = (char *) thread->stackblock
+			 + thread->stackblock_size;
 #else
       iattr->stackaddr = (char *) thread->stackblock;
 #endif

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog                 |    9 +++++++++
 nptl/allocatestack.c      |    4 ++++
 nptl/descr.h              |    4 ++--
 nptl/nptl-init.c          |    5 +----
 nptl/pthread_getattr_np.c |    7 +++++--
 5 files changed, 21 insertions(+), 8 deletions(-)


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