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| author | Russ Cox <rsc@swtch.com> | 2020-01-24 13:09:55 -0500 |
|---|---|---|
| committer | Russ Cox <rsc@swtch.com> | 2020-01-24 13:09:55 -0500 |
| commit | 4197af4122bc06cf4062ca2d1d5bc8f973e37cf1 (patch) | |
| tree | 19601cab718aed75d2d0b9808a0d3241534980a0 /src | |
| parent | 93e2e820a5551ba3d0a1e0f0fbd4c5eb65e18ce6 (diff) | |
| download | plan9port-4197af4122bc06cf4062ca2d1d5bc8f973e37cf1.tar.gz plan9port-4197af4122bc06cf4062ca2d1d5bc8f973e37cf1.tar.bz2 plan9port-4197af4122bc06cf4062ca2d1d5bc8f973e37cf1.zip | |
libthread: comment stack border a bit more
Diffstat (limited to 'src')
| -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 = |