x86/dumpstack: Save first regs set for the executive summary

Save the regs set when __die() is onvoked for the first time and print it
in oops_end().

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Link: https://lkml.kernel.org/r/20180417161124.5294-9-bp@alien8.de

1 files changed, 12 insertions, 20 deletions

diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index 82da808b5c36..ee344030fd0a 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -28,6 +28,8 @@ int panic_on_unrecovered_nmi;
 int panic_on_io_nmi;
 static int die_counter;
 
+static struct pt_regs exec_summary_regs;
+
 bool in_task_stack(unsigned long *stack, struct task_struct *task,
                    struct stack_info *info)
 {
@@ -321,6 +323,9 @@ void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
         raw_local_irq_restore(flags);
         oops_exit();
 
+        /* Executive summary in case the oops scrolled away */
+        __show_regs(&exec_summary_regs, true);
+
         if (!signr)
                 return;
         if (in_interrupt())
@@ -339,10 +344,10 @@ NOKPROBE_SYMBOL(oops_end);
 
 int __die(const char *str, struct pt_regs *regs, long err)
 {
-#ifdef CONFIG_X86_32
-        unsigned short ss;
-        unsigned long sp;
-#endif
+        /* Save the regs of the first oops for the executive summary later. */
+        if (!die_counter)
+                exec_summary_regs = *regs;
+
         printk(KERN_DEFAULT
                "%s: %04lx [#%d]%s%s%s%s%s\n", str, err & 0xffff, ++die_counter,
                IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT"         : "",
@@ -352,26 +357,13 @@ int __die(const char *str, struct pt_regs *regs, long err)
                IS_ENABLED(CONFIG_PAGE_TABLE_ISOLATION) ?
                (boot_cpu_has(X86_FEATURE_PTI) ? " PTI" : " NOPTI") : "");
 
+        show_regs(regs);
+        print_modules();
+
         if (notify_die(DIE_OOPS, str, regs, err,
                         current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
                 return 1;
 
-        print_modules();
-        show_regs(regs);
-#ifdef CONFIG_X86_32
-        if (user_mode(regs)) {
-                sp = regs->sp;
-                ss = regs->ss;
-        } else {
-                sp = kernel_stack_pointer(regs);
-                savesegment(ss, ss);
-        }
-        printk(KERN_EMERG "EIP: %pS SS:ESP: %04x:%08lx\n",
-               (void *)regs->ip, ss, sp);
-#else
-        /* Executive summary in case the oops scrolled away */
-        printk(KERN_ALERT "RIP: %pS RSP: %016lx\n", (void *)regs->ip, regs->sp);
-#endif
         return 0;
 }
 NOKPROBE_SYMBOL(__die);