runtime: x_cgo_getstackbound: initialize pthread attr

In glibc versions older than 2.32 (before commit 4721f95058),
pthread_getattr_np does not always initialize the `attr` argument,
and when it fails, it results in a NULL pointer dereference in
pthread_attr_destroy down the road.

This is the simplest way to avoid this, and an alternative to CL 585019.

Updates #65625.

Change-Id: If490fd37020b03eb084ebbdbf9ae0248916426d0
Reviewed-on: https://go-review.googlesource.com/c/go/+/587919
Auto-Submit: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Cherry Mui <cherryyz@google.com>
This commit is contained in:
Kir Kolyshkin 2024-05-23 14:12:10 -07:00 committed by Gopher Robot
parent 2fe2e4d593
commit 35ef4a9f33

View file

@ -18,6 +18,9 @@ x_cgo_getstackbound(uintptr bounds[2])
void *addr;
size_t size;
// Needed before pthread_getattr_np, too, since before glibc 2.32
// it did not call pthread_attr_init in all cases (see #65625).
pthread_attr_init(&attr);
#if defined(__GLIBC__) || (defined(__sun) && !defined(__illumos__))
// pthread_getattr_np is a GNU extension supported in glibc.
// Solaris is not glibc but does support pthread_getattr_np
@ -25,13 +28,11 @@ x_cgo_getstackbound(uintptr bounds[2])
pthread_getattr_np(pthread_self(), &attr); // GNU extension
pthread_attr_getstack(&attr, &addr, &size); // low address
#elif defined(__illumos__)
pthread_attr_init(&attr);
pthread_attr_get_np(pthread_self(), &attr);
pthread_attr_getstack(&attr, &addr, &size); // low address
#else
// We don't know how to get the current stacks, so assume they are the
// same as the default stack bounds.
pthread_attr_init(&attr);
pthread_attr_getstacksize(&attr, &size);
addr = __builtin_frame_address(0) + 4096 - size;
#endif