On Thu, Nov 12, 2020 at 01:29:06PM +0100, 赵乾利 wrote:
gcore patch:
commit 837182cc6589095c0d08f71f57953c50ad61cc19
Author: zhaoqianli <zhaoqianli(a)xiaomi.com>
Date: Thu Nov 12 19:41:01 2020 +0800
Fix register parsing error caused by miscalculation of the
starting address of the pt_regs structure on the kernel stack
Signed-off-by: zhaoqianli <zhaoqianli(a)xiaomi.com>
diff --git a/libgcore/gcore_arm64.c b/libgcore/gcore_arm64.c
index 3257389..c828fee 100644
--- a/libgcore/gcore_arm64.c
+++ b/libgcore/gcore_arm64.c
@@ -28,7 +28,7 @@ static int gpr_get(struct task_context *target,
BZERO(regs, sizeof(*regs));
- readmem(machdep->get_stacktop(target->task) - 16 - SIZE(pt_regs), KVADDR,
+ readmem(machdep->get_stacktop(target->task) -
machdep->machspec->user_eframe_offset, KVADDR,
regs, sizeof(struct user_pt_regs), "gpr_get: user_pt_regs",
gcore_verbose_error_handle());
@@ -124,7 +124,7 @@ static int compat_gpr_get(struct task_context *target,
BZERO(&pt_regs, sizeof(pt_regs));
BZERO(regs, sizeof(*regs));
- readmem(machdep->get_stacktop(target->task) - 16 - SIZE(pt_regs), KVADDR,
+ readmem(machdep->get_stacktop(target->task) -
machdep->machspec->user_eframe_offset, KVADDR,
&pt_regs, sizeof(struct pt_regs), "compat_gpr_get:
pt_regs",
gcore_verbose_error_handle());
The above patch was correct, but it looks like the version that actually
landed in the crash-gcore git[0] has a small error. The version in the
git retains the "- SIZE(pt_regs)" but that should have been be removed
as can be seen in the patch above.
[0]
https://github.com/fujitsu/crash-gcore/commit/19bfb92e50799a82f7ce6179fb3...)
So a fix like the below is needed to get valid registers:
8<--------------
From f841c41725fbab3cd4247555a550b496b57eb2a6 Mon Sep 17 00:00:00 2001
From: Vincent Whitchurch <vincent.whitchurch(a)axis.com>
Date: Tue, 9 Nov 2021 13:45:42 +0100
Subject: [PATCH] arm64: Fix pt_regs miscalculation
The user_eframe_offset includes the SIZE(pt_regs) so that should have
been removed in commit 19bfb92e50799a82f7ce6179fb35ccd82061bafd ("arm64:
Fix miscalculation of the starting address...") but that removal appears
to have got lost.
Signed-off-by: Vincent Whitchurch <vincent.whitchurch(a)axis.com>
---
src/libgcore/gcore_arm64.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/libgcore/gcore_arm64.c b/src/libgcore/gcore_arm64.c
index 678da8d..da9c647 100644
--- a/src/libgcore/gcore_arm64.c
+++ b/src/libgcore/gcore_arm64.c
@@ -29,7 +29,7 @@ static int gpr_get(struct task_context *target,
BZERO(regs, sizeof(*regs));
readmem(machdep->get_stacktop(target->task) -
- machdep->machspec->user_eframe_offset - SIZE(pt_regs), KVADDR,
+ machdep->machspec->user_eframe_offset, KVADDR,
regs, sizeof(struct user_pt_regs), "gpr_get: user_pt_regs",
gcore_verbose_error_handle());
@@ -126,7 +126,7 @@ static int compat_gpr_get(struct task_context *target,
BZERO(regs, sizeof(*regs));
readmem(machdep->get_stacktop(target->task) -
- machdep->machspec->user_eframe_offset - SIZE(pt_regs), KVADDR,
+ machdep->machspec->user_eframe_offset, KVADDR,
&pt_regs, sizeof(struct pt_regs), "compat_gpr_get: pt_regs",
gcore_verbose_error_handle());
--
2.28.0