Paul Gofman : ntdll: Respect red zone in usr1_handler() on x64.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 6f55a13169797dd073575c052a6418e3cecbcfad
URL:    https://gitlab.winehq.org/wine/wine/-/commit/6f55a13169797dd073575c052a6418e...

Author: Paul Gofman 
Date:   Mon Mar  4 19:54:54 2024 -0600

ntdll: Respect red zone in usr1_handler() on x64.

Fixes a regression introduced by
efd3d31082645fab83c6a4994705654edafa9163.

---

dlls/ntdll/unix/signal_x86_64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dlls/ntdll/unix/signal_x86_64.c b/dlls/ntdll/unix/signal_x86_64.c
index fb1bca99f3d..d071120af85 100644
--- a/dlls/ntdll/unix/signal_x86_64.c
+++ b/dlls/ntdll/unix/signal_x86_64.c
@@ -2152,7 +2152,7 @@ static void usr1_handler( int signal, siginfo_t *siginfo, void *sigcontext )
         ULONG64 saved_compaction = 0;
         struct xcontext *context;

-        context = (struct xcontext *)(((ULONG_PTR)RSP_sig(ucontext) - sizeof(*context)) & ~15);
+        context = (struct xcontext *)(((ULONG_PTR)RSP_sig(ucontext) - 128 /* red zone */ - sizeof(*context)) & ~15);
         if ((char *)context < (char *)ntdll_get_thread_data()->kernel_stack)
         {
             ERR_(seh)( "kernel stack overflow.\n" );