um: Make stack trace reliable against kernel mode faults

[sfrench/cifs-2.6.git] / arch / um / os-Linux / signal.c

diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c
index 905924b773d345b8f49de2905e62a546f6461cd9..7b605e4dfffa91305e763e7698832edcbf80d3bd 100644 (file)
--- a/arch/um/os-Linux/signal.c
+++ b/arch/um/os-Linux/signal.c
@@ -304,3 +304,11 @@ int set_signals(int enable)
 
        return ret;
 }
+
+int os_is_signal_stack(void)
+{
+       stack_t ss;
+       sigaltstack(NULL, &ss);
+
+       return ss.ss_flags & SS_ONSTACK;
+}