[PATCH v4 6/6] powerpc/traps: Show instructions on exceptions

From: Murilo Opsfelder Araujo
Date: Wed Aug 01 2018 - 17:34:33 EST


Call show_user_instructions() in arch/powerpc/kernel/traps.c to dump
instructions at faulty location, useful to debugging.

Before this patch, an unhandled signal message looked like:

pandafault[10524]: segfault (11) at 100007d0 nip 1000061c lr 7fffbd295100 code 2 in pandafault[10000000+10000]

After this patch, it looks like:

pandafault[10524]: segfault (11) at 100007d0 nip 1000061c lr 7fffbd295100 code 2 in pandafault[10000000+10000]
pandafault[10524]: code: 4bfffeec 4bfffee8 3c401002 38427f00 fbe1fff8 f821ffc1 7c3f0b78 3d22fffe
pandafault[10524]: code: 392988d0 f93f0020 e93f0020 39400048 <99490000> 39200000 7d234b78 383f0040

Signed-off-by: Murilo Opsfelder Araujo <muriloo@xxxxxxxxxxxxx>
---
arch/powerpc/kernel/traps.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index bcefbb1ee771..8494b0ff4904 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -70,6 +70,7 @@
#include <asm/hmi.h>
#include <sysdev/fsl_pci.h>
#include <asm/kprobes.h>
+#include <asm/stacktrace.h>

#if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC_CORE)
int (*__debugger)(struct pt_regs *regs) __read_mostly;
@@ -337,6 +338,8 @@ static void show_signal_msg(int signr, struct pt_regs *regs, int code,
print_vma_addr(KERN_CONT " in ", regs->nip);

pr_cont("\n");
+
+ show_user_instructions(regs);
}

void _exception_pkey(int signr, struct pt_regs *regs, int code,
--
2.17.1