1 files changed, 11 insertions, 3 deletions

diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 5b1943dc15e9..1f39f2bf7ce9 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -494,7 +494,15 @@ int start_idle_thread(void *stack, jmp_buf *switch_buf)
                     SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM,
                     SIGVTALRM, -1);
 
-        n = UML_SETJMP(&initial_jmpbuf);
+        /*
+         * Can't use UML_SETJMP or UML_LONGJMP here because they save
+         * and restore signals, with the possible side-effect of
+         * trying to handle any signals which came when they were
+         * blocked, which can't be done on this stack.
+         * Signals must be blocked when jumping back here and restored
+         * after returning to the jumper.
+         */
+        n = setjmp(initial_jmpbuf);
         switch(n){
         case INIT_JMP_NEW_THREAD:
                 (*switch_buf)[0].JB_IP = (unsigned long) new_thread_handler;
@@ -504,7 +512,7 @@ int start_idle_thread(void *stack, jmp_buf *switch_buf)
                 break;
         case INIT_JMP_CALLBACK:
                 (*cb_proc)(cb_arg);
-                UML_LONGJMP(cb_back, 1);
+                longjmp(*cb_back, 1);
                 break;
         case INIT_JMP_HALT:
                 kmalloc_ok = 0;
@@ -515,7 +523,7 @@ int start_idle_thread(void *stack, jmp_buf *switch_buf)
         default:
                 panic("Bad sigsetjmp return in start_idle_thread - %d\n", n);
         }
-        UML_LONGJMP(switch_buf, 1);
+        longjmp(*switch_buf, 1);
 }
 
 void initial_thread_cb_skas(void (*proc)(void *), void *arg)