Re: [PATCH] alternate stack dump fix.

From: Oleg Nesterov
Date: Mon Oct 04 2004 - 03:21:35 EST


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@xxxxxxxxxx>

--- 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;
-
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