Alexandre Julliard : ntdll: Don't restore the %fs register for exceptions happening inside system calls.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 0b3d65f82241aa246e0c8a49c1ec37199f539f5c
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=0b3d65f82241aa246e0c8a49c1ec37199f539f5c

Author: Alexandre Julliard <julliard at winehq.org>
Date:   Wed Dec  8 15:02:42 2021 +0100

ntdll: Don't restore the %fs register for exceptions happening inside system calls.

Signed-off-by: Alexandre Julliard <julliard at winehq.org>

---

 dlls/ntdll/unix/signal_x86_64.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/dlls/ntdll/unix/signal_x86_64.c b/dlls/ntdll/unix/signal_x86_64.c
index 9e9a96db832..d32e38875a4 100644
--- a/dlls/ntdll/unix/signal_x86_64.c
+++ b/dlls/ntdll/unix/signal_x86_64.c
@@ -355,7 +355,7 @@ static inline struct amd64_thread_data *amd64_thread_data(void)
     return (struct amd64_thread_data *)ntdll_get_thread_data()->cpu_data;
 }
 
-static BOOL is_inside_syscall( ucontext_t *sigcontext )
+static BOOL is_inside_syscall( const ucontext_t *sigcontext )
 {
     return ((char *)RSP_sig(sigcontext) >= (char *)ntdll_get_thread_data()->kernel_stack &&
             (char *)RSP_sig(sigcontext) <= (char *)amd64_thread_data()->syscall_frame);
@@ -1544,7 +1544,7 @@ static inline void init_handler( const ucontext_t *sigcontext )
 static inline void leave_handler( const ucontext_t *sigcontext )
 {
 #ifdef __linux__
-    if (fs32_sel && !is_inside_signal_stack( (void *)RSP_sig(sigcontext )))
+    if (fs32_sel && !is_inside_signal_stack( (void *)RSP_sig(sigcontext )) && !is_inside_syscall(sigcontext))
         __asm__ volatile( "movw %0,%%fs" :: "r" (fs32_sel) );
 #endif
 }