Properly fixed the tracing myself bug on 2.6 hosts.HEADmaster

3 files changed, 26 insertions, 2 deletions

diff --git a/arch/um/kernel/tt/exec_kern.c b/arch/um/kernel/tt/exec_kern.c
index 12fbbd0..644d83b 100644
--- a/arch/um/kernel/tt/exec_kern.c
+++ b/arch/um/kernel/tt/exec_kern.c
@@ -14,6 +14,7 @@
 #include "irq_user.h"
 #include "time_user.h"
 #include "mem_user.h"
+#include "signal_user.h"
 #include "os.h"
 #include "tlb.h"
 #include "mode.h"
@@ -53,7 +54,9 @@ void flush_thread_tt(void)
 	current->thread.request.u.exec.pid = new_pid;
 	unprotect_stack((unsigned long) current);
 	os_usr1_process(os_getpid());
+	change_sig(SIGUSR1, 1);
 
+	change_sig(SIGUSR1, 0);
 	enable_timer();
 	free_page(stack);
 	protect_memory(uml_reserved, high_physmem - uml_reserved, 1, 1, 0, 1);
diff --git a/arch/um/kernel/tt/process_kern.c b/arch/um/kernel/tt/process_kern.c
index dd8a55e..adfd077 100644
--- a/arch/um/kernel/tt/process_kern.c
+++ b/arch/um/kernel/tt/process_kern.c
@@ -142,6 +142,12 @@ static void new_thread_handler(int sig)
 	sti();
 	if(!run_kernel_thread(fn, arg, &current->thread.exec_buf))
 		do_exit(0);
+	
+	/* XXX No set_user_mode here because a newly execed process will
+	 * immediately segfault on its non-existent IP, coming straight back
+	 * to the signal handler, which will call set_user_mode on its way
+	 * out.  This should probably change since it's confusing.
+	 */
 }
 
 static int new_thread_proc(void *stack)
@@ -162,6 +168,7 @@ static int new_thread_proc(void *stack)
 	cli();
 	init_new_thread_stack(stack, new_thread_handler);
 	os_usr1_process(os_getpid());
+	change_sig(SIGUSR1, 1);
 	return(0);
 }
 
@@ -204,6 +211,7 @@ int fork_tramp(void *stack)
 	arch_init_thread();
 	init_new_thread_stack(stack, finish_fork_handler);
 	os_usr1_process(os_getpid());
+	change_sig(SIGUSR1, 1);
 	return(0);
 }
 
@@ -256,6 +264,9 @@ int copy_thread_tt(int nr, unsigned long clone_flags, unsigned long sp,
 	current->thread.request.op = OP_FORK;
 	current->thread.request.u.fork.pid = new_pid;
 	os_usr1_process(os_getpid());
+	change_sig(SIGUSR1, 1);
+
+	change_sig(SIGUSR1, 0);
 	return(0);
 }
 
@@ -263,12 +274,14 @@ void reboot_tt(void)
 {
 	current->thread.request.op = OP_REBOOT;
 	os_usr1_process(os_getpid());
+	change_sig(SIGUSR1, 1);
 }
 
 void halt_tt(void)
 {
 	current->thread.request.op = OP_HALT;
 	os_usr1_process(os_getpid());
+	change_sig(SIGUSR1, 1);
 }
 
 void kill_off_processes_tt(void)
@@ -297,6 +310,9 @@ void initial_thread_cb_tt(void (*proc)(void *), void *arg)
 		current->thread.request.u.cb.proc = proc;
 		current->thread.request.u.cb.arg = arg;
 		os_usr1_process(os_getpid());
+		change_sig(SIGUSR1, 1);
+
+		change_sig(SIGUSR1, 0);
 	}
 }
 
diff --git a/arch/um/kernel/tt/trap_user.c b/arch/um/kernel/tt/trap_user.c
index 7a6dbf5..00bacac 100644
--- a/arch/um/kernel/tt/trap_user.c
+++ b/arch/um/kernel/tt/trap_user.c
@@ -23,6 +23,13 @@ void sig_handler_common_tt(int sig, void *sc_ptr)
 
 	unprotect_kernel_mem();
 
+	/* This is done because to allow SIGSEGV to be delivered inside a SEGV
+	 * handler.  This can happen in copy_user, and if SEGV is disabled,
+	 * the process will die.
+	 */
+	if(sig == SIGSEGV)
+		change_sig(SIGSEGV, 1);
+
 	r = &TASK_REGS(get_current())->tt;
 	save_regs = *r;
 	is_user = user_context(SC_SP(sc));
@@ -30,7 +37,6 @@ void sig_handler_common_tt(int sig, void *sc_ptr)
 	if(sig != SIGUSR2) 
 		r->syscall = -1;
 
-	change_sig(SIGUSR1, 1);
 	info = &sig_info[sig];
 	if(!info->is_irq) unblock_signals();
 
@@ -39,7 +45,6 @@ void sig_handler_common_tt(int sig, void *sc_ptr)
 	if(is_user){
 		interrupt_end();
 		block_signals();
-		change_sig(SIGUSR1, 0);
 		set_user_mode(NULL);
 	}
 	*r = save_regs;