Re: pinpointed: PANIC caused by dequeue_signal() in current Linus

[Ingo Molnar]

the attached patch fixes the bootup crash. There were two initialization
bugs:

	- INIT_SIGNAL needs to set shared_pending.

	- exec() needs to set up newsig properly.

the second one caused the crash Anton saw.

	Ingo

--- linux/arch/i386/kernel/init_task.c.orig	Mon Sep  9 04:04:01 2002
+++ linux/arch/i386/kernel/init_task.c	Mon Sep  9 04:04:35 2002
@@ -10,7 +10,7 @@
 
 static struct fs_struct init_fs = INIT_FS;
 static struct files_struct init_files = INIT_FILES;
-static struct signal_struct init_signals = INIT_SIGNALS;
+static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
 struct mm_struct init_mm = INIT_MM(init_mm);
 
 /*
--- linux/include/linux/init_task.h.orig	Mon Sep  9 04:02:19 2002
+++ linux/include/linux/init_task.h	Mon Sep  9 04:08:08 2002
@@ -29,10 +29,11 @@
 	.mmlist		= LIST_HEAD_INIT(name.mmlist),	\
 }
 
-#define INIT_SIGNALS {	\
+#define INIT_SIGNALS(sig) {	\
 	.count		= ATOMIC_INIT(1), 		\
 	.action		= { {{0,}}, }, 			\
-	.siglock	= SPIN_LOCK_UNLOCKED 		\
+	.siglock	= SPIN_LOCK_UNLOCKED, 		\
+	.shared_pending	= { NULL, &sig.shared_pending.head, {{0}}}, \
 }
 
 /*
--- linux/fs/exec.c.orig	Mon Sep  9 04:40:49 2002
+++ linux/fs/exec.c	Mon Sep  9 04:41:28 2002
@@ -514,6 +514,8 @@
 	spin_lock_init(&newsig->siglock);
 	atomic_set(&newsig->count, 1);
 	memcpy(newsig->action, current->sig->action, sizeof(newsig->action));
+	init_sigpending(&newsig->shared_pending);
+
 	spin_lock_irq(&current->sigmask_lock);
 	current->sig = newsig;
 	spin_unlock_irq(&current->sigmask_lock);