[patch 6/6] uml: stack dump fix

From: blaisorblade
Date: Mon May 09 2005 - 18:35:20 EST


Copy (and adapt) to UML the stack code dumper used in i386 when
CONFIG_FRAME_POINTER is enabled.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@xxxxxxxx>
---

linux-2.6.12-paolo/arch/um/include/sysrq.h | 3
linux-2.6.12-paolo/arch/um/kernel/sysrq.c | 21 ++++--
linux-2.6.12-paolo/arch/um/sys-i386/sysrq.c | 80 +++++++++++++++++++++++-
linux-2.6.12-paolo/arch/um/sys-ppc/sysrq.c | 14 ----
linux-2.6.12-paolo/arch/um/sys-x86_64/sysrq.c | 11 ---
linux-2.6.12-paolo/include/asm-um/thread_info.h | 7 --
6 files changed, 100 insertions(+), 36 deletions(-)

diff -puN arch/um/kernel/sysrq.c~uml-stack-dump-fix arch/um/kernel/sysrq.c
--- linux-2.6.12/arch/um/kernel/sysrq.c~uml-stack-dump-fix 2005-05-02 15:30:15.000000000 +0200
+++ linux-2.6.12-paolo/arch/um/kernel/sysrq.c 2005-05-02 15:30:15.000000000 +0200
@@ -3,6 +3,7 @@
* Licensed under the GPL
*/

+#include "linux/config.h"
#include "linux/sched.h"
#include "linux/kernel.h"
#include "linux/module.h"
@@ -12,14 +13,14 @@
#include "sysrq.h"
#include "user_util.h"

-void show_trace(unsigned long * stack)
+/* Catch non-i386 SUBARCH's. */
+#if !defined(CONFIG_UML_X86) || defined(CONFIG_64BIT)
+void show_trace(struct task_struct *task, unsigned long * stack)
{
- /* XXX: Copy the CONFIG_FRAME_POINTER stack-walking backtrace from
- * arch/i386/kernel/traps.c, and then move this to sys-i386/sysrq.c.*/
unsigned long addr;

if (!stack) {
- stack = (unsigned long*) &stack;
+ stack = (unsigned long*) &stack;
WARN_ON(1);
}

@@ -35,6 +36,7 @@ void show_trace(unsigned long * stack)
}
printk("\n");
}
+#endif

/*
* stack dumps generator - this is used by arch-independent code.
@@ -44,7 +46,7 @@ void dump_stack(void)
{
unsigned long stack;

- show_trace(&stack);
+ show_trace(current, &stack);
}
EXPORT_SYMBOL(dump_stack);

@@ -59,7 +61,11 @@ void show_stack(struct task_struct *task
int i;

if (esp == NULL) {
- if (task != current) {
+ if (task != current && task != NULL) {
+ /* XXX: Isn't this bogus? I.e. isn't this the
+ * *userspace* stack of this task? If not so, use this
+ * even when task == current (as in i386).
+ */
esp = (unsigned long *) KSTK_ESP(task);
/* Which one? No actual difference - just coding style.*/
//esp = (unsigned long *) PT_REGS_IP(&task->thread.regs);
@@ -77,5 +83,6 @@ void show_stack(struct task_struct *task
printk("%08lx ", *stack++);
}

- show_trace(esp);
+ printk("Call Trace: \n");
+ show_trace(current, esp);
}
diff -puN arch/um/sys-i386/sysrq.c~uml-stack-dump-fix arch/um/sys-i386/sysrq.c
--- linux-2.6.12/arch/um/sys-i386/sysrq.c~uml-stack-dump-fix 2005-05-02 15:30:15.000000000 +0200
+++ linux-2.6.12-paolo/arch/um/sys-i386/sysrq.c 2005-05-02 15:31:07.000000000 +0200
@@ -3,12 +3,15 @@
* Licensed under the GPL
*/

+#include "linux/config.h"
#include "linux/kernel.h"
#include "linux/smp.h"
#include "linux/sched.h"
+#include "linux/kallsyms.h"
#include "asm/ptrace.h"
#include "sysrq.h"

+/* This is declared by <linux/sched.h> */
void show_regs(struct pt_regs *regs)
{
printk("\n");
@@ -31,5 +34,80 @@ void show_regs(struct pt_regs *regs)
0xffff & PT_REGS_DS(regs),
0xffff & PT_REGS_ES(regs));

- show_trace((unsigned long *) &regs);
+ show_trace(NULL, (unsigned long *) &regs);
}
+
+/* Copied from i386. */
+static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
+{
+ return p > (void *)tinfo &&
+ p < (void *)tinfo + THREAD_SIZE - 3;
+}
+
+/* Adapted from i386 (we also print the address we read from). */
+static inline unsigned long print_context_stack(struct thread_info *tinfo,
+ unsigned long *stack, unsigned long ebp)
+{
+ unsigned long addr;
+
+#ifdef CONFIG_FRAME_POINTER
+ while (valid_stack_ptr(tinfo, (void *)ebp)) {
+ addr = *(unsigned long *)(ebp + 4);
+ printk("%08lx: [<%08lx>]", ebp + 4, addr);
+ print_symbol(" %s", addr);
+ printk("\n");
+ ebp = *(unsigned long *)ebp;
+ }
+#else
+ while (valid_stack_ptr(tinfo, stack)) {
+ addr = *stack;
+ if (__kernel_text_address(addr)) {
+ printk("%08lx: [<%08lx>]", (unsigned long) stack, addr);
+ print_symbol(" %s", addr);
+ printk("\n");
+ }
+ stack++;
+ }
+#endif
+ return ebp;
+}
+
+void show_trace(struct task_struct* task, unsigned long * stack)
+{
+ unsigned long ebp;
+ struct thread_info *context;
+
+ /* Turn this into BUG_ON if possible. */
+ if (!stack) {
+ stack = (unsigned long*) &stack;
+ printk("show_trace: got NULL stack, implicit assumption task == current");
+ WARN_ON(1);
+ }
+
+ if (!task)
+ task = current;
+
+ if (task != current) {
+ //ebp = (unsigned long) KSTK_EBP(task);
+ /* Which one? No actual difference - just coding style.*/
+ ebp = (unsigned long) PT_REGS_EBP(&task->thread.regs);
+ } else {
+ asm ("movl %%ebp, %0" : "=r" (ebp) : );
+ }
+
+ context = (struct thread_info *)
+ ((unsigned long)stack & (~(THREAD_SIZE - 1)));
+ print_context_stack(context, stack, ebp);
+
+ /*while (((long) stack & (THREAD_SIZE-1)) != 0) {
+ addr = *stack;
+ if (__kernel_text_address(addr)) {
+ printk("%08lx: [<%08lx>]", (unsigned long) stack, addr);
+ print_symbol(" %s", addr);
+ printk("\n");
+ }
+ stack++;
+ }*/
+ printk("\n");
+}
+
diff -puN include/asm-um/thread_info.h~uml-stack-dump-fix include/asm-um/thread_info.h
--- linux-2.6.12/include/asm-um/thread_info.h~uml-stack-dump-fix 2005-05-02 15:30:15.000000000 +0200
+++ linux-2.6.12-paolo/include/asm-um/thread_info.h 2005-05-02 15:30:15.000000000 +0200
@@ -41,18 +41,17 @@ struct thread_info {
#define init_thread_info (init_thread_union.thread_info)
#define init_stack (init_thread_union.stack)

+#define THREAD_SIZE ((1 << CONFIG_KERNEL_STACK_ORDER) * PAGE_SIZE)
/* how to get the thread information struct from C */
static inline struct thread_info *current_thread_info(void)
{
struct thread_info *ti;
- unsigned long mask = PAGE_SIZE *
- (1 << CONFIG_KERNEL_STACK_ORDER) - 1;
- ti = (struct thread_info *) (((unsigned long) &ti) & ~mask);
+ unsigned long mask = THREAD_SIZE - 1;
+ ti = (struct thread_info *) (((unsigned long) &ti) & ~mask);
return ti;
}

/* thread information allocation */
-#define THREAD_SIZE ((1 << CONFIG_KERNEL_STACK_ORDER) * PAGE_SIZE)
#define alloc_thread_info(tsk) \
((struct thread_info *) kmalloc(THREAD_SIZE, GFP_KERNEL))
#define free_thread_info(ti) kfree(ti)
diff -puN arch/um/sys-x86_64/sysrq.c~uml-stack-dump-fix arch/um/sys-x86_64/sysrq.c
--- linux-2.6.12/arch/um/sys-x86_64/sysrq.c~uml-stack-dump-fix 2005-05-02 15:30:15.000000000 +0200
+++ linux-2.6.12-paolo/arch/um/sys-x86_64/sysrq.c 2005-05-02 15:30:15.000000000 +0200
@@ -36,14 +36,5 @@ void __show_regs(struct pt_regs * regs)
void show_regs(struct pt_regs *regs)
{
__show_regs(regs);
- show_trace((unsigned long *) &regs);
+ show_trace(current, (unsigned long *) &regs);
}
-
-/* Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only. This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
diff -puN arch/um/include/sysrq.h~uml-stack-dump-fix arch/um/include/sysrq.h
--- linux-2.6.12/arch/um/include/sysrq.h~uml-stack-dump-fix 2005-05-02 15:30:15.000000000 +0200
+++ linux-2.6.12-paolo/arch/um/include/sysrq.h 2005-05-02 15:30:15.000000000 +0200
@@ -1,6 +1,7 @@
#ifndef __UM_SYSRQ_H
#define __UM_SYSRQ_H

-extern void show_trace(unsigned long *stack);
+struct task_struct;
+extern void show_trace(struct task_struct* task, unsigned long *stack);

#endif
diff -puN arch/um/sys-ppc/sysrq.c~uml-stack-dump-fix arch/um/sys-ppc/sysrq.c
--- linux-2.6.12/arch/um/sys-ppc/sysrq.c~uml-stack-dump-fix 2005-05-02 15:30:15.000000000 +0200
+++ linux-2.6.12-paolo/arch/um/sys-ppc/sysrq.c 2005-05-02 15:30:15.000000000 +0200
@@ -27,17 +27,5 @@ void show_regs(struct pt_regs_subarch *r
0xffff & regs->xds, 0xffff & regs->xes);
#endif

- show_trace(&regs->gpr[1]);
+ show_trace(current, &regs->gpr[1]);
}
-
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only. This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
_
-
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