From: Bodo Stroesser <bstroesser@fujitsu-siemens.com>

Masking SIGSEGV in stub_segv_handler is bad. If a SIGSEGV happens
while stub_segv_handler is running, the host will force the signal,
so the child is killed. This makes stub_segv_handler hard to
debug.
So, we add SA_NOMASK to the flags in sigaction, to have SIGSEGV
unblocked, ebven while the handler runs.

Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
---


diff -puN arch/um/os-Linux/skas/process.c~fix-SEGV-masking arch/um/os-Linux/skas/process.c
--- linux-2.6.12-rc4/arch/um/os-Linux/skas/process.c~fix-SEGV-masking	2005-07-15 13:33:55.240371787 +0200
+++ linux-2.6.12-rc4-root/arch/um/os-Linux/skas/process.c	2005-07-15 13:35:37.379660671 +0200
@@ -182,7 +182,7 @@ static int userspace_tramp(void *stack)
 				  (unsigned long) &__syscall_stub_start;
 
 		set_sigstack((void *) UML_CONFIG_STUB_DATA, page_size());
-		set_handler(SIGSEGV, (void *) v, SA_ONSTACK,
+		set_handler(SIGSEGV, (void *) v, SA_ONSTACK | SA_NOMASK,
 			    SIGIO, SIGWINCH, SIGALRM, SIGVTALRM,
 			    SIGUSR1, -1);
 	}
_