diff options
| -rw-r--r-- | src/libthread/thread.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/src/libthread/thread.c b/src/libthread/thread.c index 2e654863..f657b5b2 100644 --- a/src/libthread/thread.c +++ b/src/libthread/thread.c @@ -136,10 +136,16 @@ threadalloc(void (*fn)(void*), void *arg, uint stack) sysfatal("threadalloc getcontext: %r"); //print("makecontext sp=%p t=%p startfn=%p\n", (char*)t->stk+t->stksize, t, t->startfn); - /* call makecontext to do the real work. */ - /* leave a few words open on both ends */ - t->context.uc.uc_stack.ss_sp = (void*)(t->stk+8); - t->context.uc.uc_stack.ss_size = t->stksize-64; + /* + * Call makecontext to do the real work. + * To avoid various mistakes on other system software, + * debuggers, and so on, don't get too close to both + * ends of the stack. Just staying away is much easier + * than debugging everything (outside our control) + * that has off-by-one errors. + */ + t->context.uc.uc_stack.ss_sp = (void*)(t->stk+64); + t->context.uc.uc_stack.ss_size = t->stksize-2*64; #if defined(__sun__) && !defined(__MAKECONTEXT_V2_SOURCE) /* sigh */ /* can avoid this with __MAKECONTEXT_V2_SOURCE but only on SunOS 5.9 */ t->context.uc.uc_stack.ss_sp = |