From 77f6af778dc23514d897f4fdc7935329285ecb1b Mon Sep 17 00:00:00 2001 From: Jeff Dike Date: Sun, 6 May 2007 14:51:40 -0700 Subject: [PATCH] uml: don't try to handle signals on initial process stack Code running on the initial UML stack can't receive or process signals since current must be valid when IRQs are handled, and there is no current for this stack. So, instead of using UML_LONGJMP and UML_SETJMP, which are careful to save and restore signal state, and, as a side-effect, handle any deferred signals, start_idle_thread must use the bare equivalents, which don't do anything with signals. Signed-off-by: Jeff Dike Cc: Paolo 'Blaisorblade' Giarrusso Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/os-Linux/skas/process.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c index 5b1943dc15..1f39f2bf7c 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) -- 2.20.1