[PATCH 8/9] x86/dumpstack: Save first regs set for the executive summary

Borislav Petkov
2018-04-17T16:14:14Z

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

Signed-off-by: Borislav Petkov <bp@suse.de>
---
arch/x86/kernel/dumpstack.c | 32 ++++++++++++--------------------
1 file 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);
--
2.13.0