x86: add the capability to print fuzzy backtraces

For enhancing the 32 bit EBP based backtracer, I need the capability
for the backtracer to tell it's customer that an entry is either
reliable or unreliable, and the backtrace printing code then needs to
print the unreliable ones slightly different.

This patch adds the basic capability, the next patch will add a user
of this capability.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/kernel/pci-gart_64.c b/arch/x86/kernel/pci-gart_64.c
index d2b46b48941226ee5f46b0c7a6faad6f8b9f78b7..04ca5c5221d7b12f3ac15ca8b834ffef37df2ac4 100644 (file)
--- a/arch/x86/kernel/pci-gart_64.c
+++ b/arch/x86/kernel/pci-gart_64.c
@@ -167,7 +167,7 @@ static void dump_leak(void)
               iommu_leak_pages);
        for (i = 0; i < iommu_leak_pages; i += 2) {
                printk(KERN_DEBUG "%lu: ", iommu_pages-i);
-               printk_address((unsigned long) iommu_leak_tab[iommu_pages-i]);
+               printk_address((unsigned long) iommu_leak_tab[iommu_pages-i], 0);
                printk(KERN_CONT "%c", (i+1)%2 == 0 ? '\n' : ' ');
        }
        printk(KERN_DEBUG "\n");

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index a0130eb2fa50a088a20025ffd0c92c72f3f5a26a..383760bfd283bf10bbfbefef486ca9abbe84de1b 100644 (file)
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -329,7 +329,7 @@ void __show_regs(struct pt_regs * regs)
                (int)strcspn(init_utsname()->version, " "),
                init_utsname()->version);
        printk("RIP: %04lx:[<%016lx>] ", regs->cs & 0xffff, regs->ip);
-       printk_address(regs->ip);
+       printk_address(regs->ip, regs->bp);
        printk("RSP: %04lx:%016lx  EFLAGS: %08lx\n", regs->ss, regs->sp,
                regs->flags);
        printk("RAX: %016lx RBX: %016lx RCX: %016lx\n",
@@ -377,7 +377,7 @@ void show_regs(struct pt_regs *regs)
 {
        printk("CPU %d:", smp_processor_id());
        __show_regs(regs);
-       show_trace(NULL, regs, (void *)(regs + 1));
+       show_trace(NULL, regs, (void *)(regs + 1), regs->bp);
 }
 
 /*

diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c
index c571edd11878ba26ebcd91c9908369043db8967f..8c4e4f5bf0403fa0ffaa42e89f9261e2f4fa4fe1 100644 (file)
--- a/arch/x86/kernel/stacktrace.c
+++ b/arch/x86/kernel/stacktrace.c
@@ -22,7 +22,7 @@ static int save_stack_stack(void *data, char *name)
        return -1;
 }
 
-static void save_stack_address(void *data, unsigned long addr)
+static void save_stack_address(void *data, unsigned long addr, int reliable)
 {
        struct stack_trace *trace = (struct stack_trace *)data;
        if (trace->skip > 0) {

diff --git a/arch/x86/kernel/traps_32.c b/arch/x86/kernel/traps_32.c
index acc9af260facc598ae0dcaf833431503a93d815f..8ef8a9ddfec60aceee9b37f2fca29df45c4d7c3d 100644 (file)
--- a/arch/x86/kernel/traps_32.c
+++ b/arch/x86/kernel/traps_32.c
@@ -126,7 +126,7 @@ static inline unsigned long print_context_stack(struct thread_info *tinfo,
 
                addr = frame->return_address;
                if (__kernel_text_address(addr))
-                       ops->address(data, addr);
+                       ops->address(data, addr, 1);
                /*
                 * break out of recursive entries (such as
                 * end_of_stack_stop_unwind_function). Also,
@@ -145,7 +145,7 @@ static inline unsigned long print_context_stack(struct thread_info *tinfo,
 
                addr = *stack++;
                if (__kernel_text_address(addr))
-                       ops->address(data, addr);
+                       ops->address(data, addr, 1);
        }
 #endif
        return bp;
@@ -220,9 +220,11 @@ static int print_trace_stack(void *data, char *name)
 /*
  * Print one address/symbol entries per line.
  */
-static void print_trace_address(void *data, unsigned long addr)
+static void print_trace_address(void *data, unsigned long addr, int reliable)
 {
        printk("%s [<%08lx>] ", (char *)data, addr);
+       if (!reliable)
+               printk("? ");
        print_symbol("%s\n", addr);
        touch_nmi_watchdog();
 }

diff --git a/arch/x86/kernel/traps_64.c b/arch/x86/kernel/traps_64.c
index 37b07d08704b1b787f307400f13ad8b5ce062ecc..62c4d8f46ee9db3770216890e6d09b6f2512fb65 100644 (file)
--- a/arch/x86/kernel/traps_64.c
+++ b/arch/x86/kernel/traps_64.c
@@ -99,13 +99,14 @@ static inline void preempt_conditional_cli(struct pt_regs *regs)
 int kstack_depth_to_print = 12;
 
 #ifdef CONFIG_KALLSYMS
-void printk_address(unsigned long address)
+void printk_address(unsigned long address, int reliable)
 {
        unsigned long offset = 0, symsize;
        const char *symname;
        char *modname;
        char *delim = ":";
        char namebuf[128];
+       char reliab[4] = "";;
 
        symname = kallsyms_lookup(address, &symsize, &offset,
                                        &modname, namebuf);
@@ -113,13 +114,16 @@ void printk_address(unsigned long address)
                printk(" [<%016lx>]\n", address);
                return;
        }
+       if (!reliable)
+               strcpy(reliab, "? ");
+
        if (!modname)
                modname = delim = "";           
-       printk(" [<%016lx>] %s%s%s%s+0x%lx/0x%lx\n",
-               address, delim, modname, delim, symname, offset, symsize);
+       printk(" [<%016lx>] %s%s%s%s%s+0x%lx/0x%lx\n",
+               address, reliab, delim, modname, delim, symname, offset, symsize);
 }
 #else
-void printk_address(unsigned long address)
+void printk_address(unsigned long address, int reliable)
 {
        printk(" [<%016lx>]\n", address);
 }
@@ -215,7 +219,7 @@ static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
 }
 
 void dump_trace(struct task_struct *tsk, struct pt_regs *regs,
-               unsigned long *stack,
+               unsigned long *stack, unsigned long bp,
                const struct stacktrace_ops *ops, void *data)
 {
        const unsigned cpu = get_cpu();
@@ -252,7 +256,7 @@ void dump_trace(struct task_struct *tsk, struct pt_regs *regs,
                         * down the cause of the crash will be able to figure \
                         * out the call path that was taken. \
                         */ \
-                       ops->address(data, addr);   \
+                       ops->address(data, addr, 1);   \
                } \
        } while (0)
 
@@ -331,10 +335,10 @@ static int print_trace_stack(void *data, char *name)
        return 0;
 }
 
-static void print_trace_address(void *data, unsigned long addr)
+static void print_trace_address(void *data, unsigned long addr, int reliable)
 {
        touch_nmi_watchdog();
-       printk_address(addr);
+       printk_address(addr, reliable);
 }
 
 static const struct stacktrace_ops print_trace_ops = {
@@ -345,15 +349,17 @@ static const struct stacktrace_ops print_trace_ops = {
 };
 
 void
-show_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long *stack)
+show_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long *stack,
+               unsigned long bp)
 {
        printk("\nCall Trace:\n");
-       dump_trace(tsk, regs, stack, &print_trace_ops, NULL);
+       dump_trace(tsk, regs, stack, bp, &print_trace_ops, NULL);
        printk("\n");
 }
 
 static void
-_show_stack(struct task_struct *tsk, struct pt_regs *regs, unsigned long *sp)
+_show_stack(struct task_struct *tsk, struct pt_regs *regs, unsigned long *sp,
+                                                       unsigned long bp)
 {
        unsigned long *stack;
        int i;
@@ -387,12 +393,12 @@ _show_stack(struct task_struct *tsk, struct pt_regs *regs, unsigned long *sp)
                printk(" %016lx", *stack++);
                touch_nmi_watchdog();
        }
-       show_trace(tsk, regs, sp);
+       show_trace(tsk, regs, sp, bp);
 }
 
 void show_stack(struct task_struct *tsk, unsigned long * sp)
 {
-       _show_stack(tsk, NULL, sp);
+       _show_stack(tsk, NULL, sp, 0);
 }
 
 /*
@@ -401,13 +407,14 @@ void show_stack(struct task_struct *tsk, unsigned long * sp)
 void dump_stack(void)
 {
        unsigned long dummy;
+       unsigned long bp = 0;
 
        printk("Pid: %d, comm: %.20s %s %s %.*s\n",
                current->pid, current->comm, print_tainted(),
                init_utsname()->release,
                (int)strcspn(init_utsname()->version, " "),
                init_utsname()->version);
-       show_trace(NULL, NULL, &dummy);
+       show_trace(NULL, NULL, &dummy, bp);
 }
 
 EXPORT_SYMBOL(dump_stack);
@@ -432,7 +439,7 @@ void show_registers(struct pt_regs *regs)
         */
        if (in_kernel) {
                printk("Stack: ");
-               _show_stack(NULL, regs, (unsigned long*)sp);
+               _show_stack(NULL, regs, (unsigned long *)sp, regs->bp);
 
                printk("\nCode: ");
                if (regs->ip < PAGE_OFFSET)
@@ -527,7 +534,7 @@ int __kprobes __die(const char * str, struct pt_regs * regs, long err)
        add_taint(TAINT_DIE);
        /* Executive summary in case the oops scrolled away */
        printk(KERN_ALERT "RIP ");
-       printk_address(regs->ip);
+       printk_address(regs->ip, regs->bp);
        printk(" RSP <%016lx>\n", regs->sp);
        if (kexec_should_crash(current))
                crash_kexec(regs);

diff --git a/arch/x86/mm/fault_64.c b/arch/x86/mm/fault_64.c
index e82832961d7246519169ad706f2545f36e4478c6..cf7e99895b91e81f046db10ccb9485a395b174d2 100644 (file)
--- a/arch/x86/mm/fault_64.c
+++ b/arch/x86/mm/fault_64.c
@@ -578,7 +578,7 @@ no_context:
        else
                printk(KERN_ALERT "Unable to handle kernel paging request");
        printk(" at %016lx RIP: \n" KERN_ALERT, address);
-       printk_address(regs->ip);
+       printk_address(regs->ip, regs->bp);
        dump_pagetable(address);
        tsk->thread.cr2 = address;
        tsk->thread.trap_no = 14;

diff --git a/arch/x86/oprofile/backtrace.c b/arch/x86/oprofile/backtrace.c
index cc353a0b183e297d2fd241d145869ee94c542612..671a7ecf11aacbfa5b613f285ae60ec40111dce6 100644 (file)
--- a/arch/x86/oprofile/backtrace.c
+++ b/arch/x86/oprofile/backtrace.c
@@ -32,7 +32,7 @@ static int backtrace_stack(void *data, char *name)
        return 0;
 }
 
-static void backtrace_address(void *data, unsigned long addr)
+static void backtrace_address(void *data, unsigned long addr, int reliable)
 {
        unsigned int *depth = data;
 

diff --git a/include/asm-x86/kdebug.h b/include/asm-x86/kdebug.h
index e9f42d1ac38fb09097957304d3fc4373d11f4731..dd442a1632c00897800700bc6d01bc68c1f71c71 100644 (file)
--- a/include/asm-x86/kdebug.h
+++ b/include/asm-x86/kdebug.h
@@ -22,12 +22,13 @@ enum die_val {
        DIE_PAGE_FAULT,
 };
 
-extern void printk_address(unsigned long address);
+extern void printk_address(unsigned long address, int reliable);
 extern void die(const char *,struct pt_regs *,long);
 extern int __must_check __die(const char *, struct pt_regs *, long);
 extern void show_registers(struct pt_regs *regs);
 extern void __show_registers(struct pt_regs *, int all);
-extern void show_trace(struct task_struct *, struct pt_regs *, unsigned long *);
+extern void show_trace(struct task_struct *t, struct pt_regs *regs,
+                       unsigned long *sp, unsigned long bp);
 extern void __show_regs(struct pt_regs *regs);
 extern void show_regs(struct pt_regs *regs);
 extern void dump_pagetable(unsigned long);

diff --git a/include/asm-x86/stacktrace.h b/include/asm-x86/stacktrace.h
index 70dd5bae32350fbd0c1d90cabdbeda9cf0740818..30f82526a8e285547ea890febb757890d3ad4cde 100644 (file)
--- a/include/asm-x86/stacktrace.h
+++ b/include/asm-x86/stacktrace.h
@@ -9,12 +9,13 @@ struct stacktrace_ops {
        void (*warning)(void *data, char *msg);
        /* msg must contain %s for the symbol */
        void (*warning_symbol)(void *data, char *msg, unsigned long symbol);
-       void (*address)(void *data, unsigned long address);
+       void (*address)(void *data, unsigned long address, int reliable);
        /* On negative return stop dumping */
        int (*stack)(void *data, char *name);
 };
 
-void dump_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long *stack,
+void dump_trace(struct task_struct *tsk, struct pt_regs *regs,
+               unsigned long *stack, unsigned long bp,
                const struct stacktrace_ops *ops, void *data);
 
 #endif