Re: [PATCH] alternate stack dump fix.

[Oleg Nesterov <oleg@tv-sign.ru>]

Oleg Nesterov wrote:
>
> > Andrew Morton wrote:
> >
> > But it conflicts in a big way with Kirill's patch.  Could you redo it
> > against 2.6.9-rc3-mm1, or against just
>
> For your convenience, i will post the same patch against mm tree with those
> 3 patches reverted in a separate message.

Against	2.6.9-rc3-mm1 +
	-R fix-of-stack-dump-in-soft-hardirqs-build-fix.patch +
	-R fix-of-stack-dump-in-soft-hardirqs-cleanup.patch +
	-R fix-of-stack-dump-in-soft-hardirqs.patch

Oleg.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>

--- rc3-mm1/arch/i386/kernel/traps.c~	Mon Oct  4 10:46:10 2004
+++ rc3-mm1/arch/i386/kernel/traps.c	Mon Oct  4 10:56:22 2004
@@ -105,15 +105,6 @@ int register_die_notifier(struct notifie
 	return err;
 }
 
-static int valid_stack_ptr(struct task_struct *task, void *p)
-{
-	if (p <= (void *)task->thread_info)
-		return 0;
-	if (kstack_end(p))
-		return 0;
-	return 1;
-}
-
 #ifdef CONFIG_KGDB
 extern void sysenter_past_esp(void);
 #include <asm/kgdb.h>
@@ -147,28 +138,27 @@ void breakpoint(void)
 #define	CHK_REMOTE_DEBUG(trapnr,signr,error_code,regs,after)
 #endif
 
+static int valid_stack_ptr(struct thread_info *tinfo, void *p)
+{
+	return	p > (void *)tinfo &&
+		p < (void *)tinfo + THREAD_SIZE - 3;
+}
 
-#ifdef CONFIG_FRAME_POINTER
-static void print_context_stack(struct task_struct *task, unsigned long *stack,
+static unsigned long print_context_stack(struct thread_info *tinfo, unsigned long *stack,
 			 unsigned long ebp)
 {
 	unsigned long addr;
 
-	while (valid_stack_ptr(task, (void *)ebp)) {
+#ifdef	CONFIG_FRAME_POINTER
+	while (valid_stack_ptr(tinfo, (void *)ebp)) {
 		addr = *(unsigned long *)(ebp + 4);
 		printk(" [<%08lx>] ", addr);
 		print_symbol("%s", addr);
 		printk("\n");
 		ebp = *(unsigned long *)ebp;
 	}
-}
 #else
-static void print_context_stack(struct task_struct *task, unsigned long *stack,
-			 unsigned long ebp)
-{
-	unsigned long addr;
-
-	while (!kstack_end(stack)) {
+	while (valid_stack_ptr(tinfo, stack)) {
 		addr = *stack++;
 		if (__kernel_text_address(addr)) {
 			printk(" [<%08lx>]", addr);
@@ -176,8 +166,9 @@ static void print_context_stack(struct t
 			printk("\n");
 		}
 	}
-}
 #endif
+	return ebp;
+}
 
 void show_trace(struct task_struct *task, unsigned long * stack)
 {
@@ -186,11 +177,6 @@ void show_trace(struct task_struct *task
 	if (!task)
 		task = current;
 
-	if (!valid_stack_ptr(task, stack)) {
-		printk("Stack pointer is garbage, not printing trace\n");
-		return;
-	}
-
 	if (task == current) {
 		/* Grab ebp right from our regs */
 		asm ("movl %%ebp, %0" : "=r" (ebp) : );
@@ -203,7 +189,7 @@ void show_trace(struct task_struct *task
 		struct thread_info *context;
 		context = (struct thread_info *)
 			((unsigned long)stack & (~(THREAD_SIZE - 1)));
-		print_context_stack(task, stack, ebp);
+		ebp = print_context_stack(context, stack, ebp);
 		stack = (unsigned long*)context->previous_esp;
 		if (!stack)
 			break;