Merge tag 'tty-4.15-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

[sfrench/cifs-2.6.git] / arch / x86 / kernel / dumpstack.c

diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index f13b4c00a5de4b7a7b36c40d27311672bcc9d05c..5fa110699ed275fe81dc9d8f678a2a2f8902017e 100644 (file)
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -18,6 +18,7 @@
 #include <linux/nmi.h>
 #include <linux/sysfs.h>
 
+#include <asm/cpu_entry_area.h>
 #include <asm/stacktrace.h>
 #include <asm/unwind.h>
 
@@ -43,6 +44,24 @@ bool in_task_stack(unsigned long *stack, struct task_struct *task,
        return true;
 }
 
+bool in_entry_stack(unsigned long *stack, struct stack_info *info)
+{
+       struct entry_stack *ss = cpu_entry_stack(smp_processor_id());
+
+       void *begin = ss;
+       void *end = ss + 1;
+
+       if ((void *)stack < begin || (void *)stack >= end)
+               return false;
+
+       info->type      = STACK_TYPE_ENTRY;
+       info->begin     = begin;
+       info->end       = end;
+       info->next_sp   = NULL;
+
+       return true;
+}
+
 static void printk_stack_address(unsigned long address, int reliable,
                                 char *log_lvl)
 {
@@ -50,6 +69,28 @@ static void printk_stack_address(unsigned long address, int reliable,
        printk("%s %s%pB\n", log_lvl, reliable ? "" : "? ", (void *)address);
 }
 
+void show_iret_regs(struct pt_regs *regs)
+{
+       printk(KERN_DEFAULT "RIP: %04x:%pS\n", (int)regs->cs, (void *)regs->ip);
+       printk(KERN_DEFAULT "RSP: %04x:%016lx EFLAGS: %08lx", (int)regs->ss,
+               regs->sp, regs->flags);
+}
+
+static void show_regs_safe(struct stack_info *info, struct pt_regs *regs)
+{
+       if (on_stack(info, regs, sizeof(*regs)))
+               __show_regs(regs, 0);
+       else if (on_stack(info, (void *)regs + IRET_FRAME_OFFSET,
+                         IRET_FRAME_SIZE)) {
+               /*
+                * When an interrupt or exception occurs in entry code, the
+                * full pt_regs might not have been saved yet.  In that case
+                * just print the iret frame.
+                */
+               show_iret_regs(regs);
+       }
+}
+
 void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
                        unsigned long *stack, char *log_lvl)
 {
@@ -71,31 +112,35 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
         * - task stack
         * - interrupt stack
         * - HW exception stacks (double fault, nmi, debug, mce)
+        * - entry stack
         *
-        * x86-32 can have up to three stacks:
+        * x86-32 can have up to four stacks:
         * - task stack
         * - softirq stack
         * - hardirq stack
+        * - entry stack
         */
        for (regs = NULL; stack; stack = PTR_ALIGN(stack_info.next_sp, sizeof(long))) {
                const char *stack_name;
 
-               /*
-                * If we overflowed the task stack into a guard page, jump back
-                * to the bottom of the usable stack.
-                */
-               if (task_stack_page(task) - (void *)stack < PAGE_SIZE)
-                       stack = task_stack_page(task);
-
-               if (get_stack_info(stack, task, &stack_info, &visit_mask))
-                       break;
+               if (get_stack_info(stack, task, &stack_info, &visit_mask)) {
+                       /*
+                        * We weren't on a valid stack.  It's possible that
+                        * we overflowed a valid stack into a guard page.
+                        * See if the next page up is valid so that we can
+                        * generate some kind of backtrace if this happens.
+                        */
+                       stack = (unsigned long *)PAGE_ALIGN((unsigned long)stack);
+                       if (get_stack_info(stack, task, &stack_info, &visit_mask))
+                               break;
+               }
 
                stack_name = stack_type_name(stack_info.type);
                if (stack_name)
                        printk("%s <%s>\n", log_lvl, stack_name);
 
-               if (regs && on_stack(&stack_info, regs, sizeof(*regs)))
-                       __show_regs(regs, 0);
+               if (regs)
+                       show_regs_safe(&stack_info, regs);
 
                /*
                 * Scan the stack, printing any text addresses we find.  At the
@@ -119,7 +164,7 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
 
                        /*
                         * Don't print regs->ip again if it was already printed
-                        * by __show_regs() below.
+                        * by show_regs_safe() below.
                         */
                        if (regs && stack == &regs->ip)
                                goto next;
@@ -155,8 +200,8 @@ next:
 
                        /* if the frame has entry regs, print them */
                        regs = unwind_get_entry_regs(&state);
-                       if (regs && on_stack(&stack_info, regs, sizeof(*regs)))
-                               __show_regs(regs, 0);
+                       if (regs)
+                               show_regs_safe(&stack_info, regs);
                }
 
                if (stack_name)
@@ -252,11 +297,13 @@ int __die(const char *str, struct pt_regs *regs, long err)
        unsigned long sp;
 #endif
        printk(KERN_DEFAULT
-              "%s: %04lx [#%d]%s%s%s%s\n", str, err & 0xffff, ++die_counter,
+              "%s: %04lx [#%d]%s%s%s%s%s\n", str, err & 0xffff, ++die_counter,
               IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT"         : "",
               IS_ENABLED(CONFIG_SMP)     ? " SMP"             : "",
               debug_pagealloc_enabled()  ? " DEBUG_PAGEALLOC" : "",
-              IS_ENABLED(CONFIG_KASAN)   ? " KASAN"           : "");
+              IS_ENABLED(CONFIG_KASAN)   ? " KASAN"           : "",
+              IS_ENABLED(CONFIG_PAGE_TABLE_ISOLATION) ?
+              (boot_cpu_has(X86_FEATURE_PTI) ? " PTI" : " NOPTI") : "");
 
        if (notify_die(DIE_OOPS, str, regs, err,
                        current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)