69 lines
2.5 KiB
Diff
69 lines
2.5 KiB
Diff
From 91a76958e4a8a9fb67ac61166ff36e8dc961b3b9 Mon Sep 17 00:00:00 2001
|
|
From: HATAYAMA Daisuke <d.hatayama@fujitsu.com>
|
|
Date: Wed, 7 Jun 2023 18:37:33 +0900
|
|
Subject: [PATCH 4/5] Revert "Fix segfault in arm64_is_kernel_exception_frame()
|
|
when corrupt stack pointer address is given"
|
|
|
|
This reverts commit 9868ebc8e648e5791764a51567a23efae7170d9b.
|
|
|
|
The commit 9868ebc8e648e5791764a51567a23efae7170d9b causes the issue
|
|
that bt command fails to show backtraces for the tasks that is running
|
|
in the user mode at the moment of the kernel panic as follows:
|
|
|
|
crash> bt 1734
|
|
PID: 1734 TASK: ffff000000392200 CPU: 4 COMMAND: "insmod"
|
|
bt: invalid stack pointer is given
|
|
|
|
The root cause is that while the commit added a sanity check into
|
|
STACK_OFFSET_TYPE() to validate if a given candidate address of any
|
|
interrupt or exception frame is contained within the range of the
|
|
corresponding kernel stack, the premise that the STACK_OFFSET_TYPE()
|
|
should not return out-of-the-buffer address, is wrong.
|
|
|
|
Reexamining the relevant surrounding part of the backtracing code, it
|
|
looks to me now that the STACK_OFFSET_TYPE() is originally expected to
|
|
return an out-of-the-buffer address, like the address of the top of
|
|
the corresponding kernel stack, e.g. at here:
|
|
|
|
static int
|
|
arm64_in_kdump_text(struct bt_info *bt, struct arm64_stackframe *frame)
|
|
{
|
|
...
|
|
if (bt->flags & BT_USER_SPACE)
|
|
start = (ulong *)&bt->stackbuf[(ulong)(STACK_OFFSET_TYPE(bt->stacktop))];
|
|
else {
|
|
|
|
Note that the above bt 1734 aborts here.
|
|
|
|
Hence, the current implementation policy around STACK_OFFSET_TYPE()
|
|
looks that the caller side is responsible for understanding the fact
|
|
in advance and for avoiding making buffer overrun carefully.
|
|
|
|
To fix this issue, revert the commit.
|
|
|
|
Signed-off-by: HATAYAMA Daisuke <d.hatayama@fujitsu.com>
|
|
Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
|
|
---
|
|
defs.h | 5 +----
|
|
1 file changed, 1 insertion(+), 4 deletions(-)
|
|
|
|
diff --git a/defs.h b/defs.h
|
|
index bfda0c48d37b..3e7d6cfbc6a8 100644
|
|
--- a/defs.h
|
|
+++ b/defs.h
|
|
@@ -976,10 +976,7 @@ struct bt_info {
|
|
|
|
#define STACK_OFFSET_TYPE(OFF) \
|
|
(((ulong)(OFF) > STACKSIZE()) ? \
|
|
- (((ulong)(OFF) < (ulong)(bt->stackbase) || (ulong)(OFF) >= (ulong)(bt->stackbase) + STACKSIZE()) ? \
|
|
- error(FATAL, "invalid stack pointer is given\n") : \
|
|
- (ulong)((ulong)(OFF) - (ulong)(bt->stackbase))) : \
|
|
- (ulong)(OFF))
|
|
+ (ulong)((ulong)(OFF) - (ulong)(bt->stackbase)) : (ulong)(OFF))
|
|
|
|
#define GET_STACK_ULONG(OFF) \
|
|
*((ulong *)((char *)(&bt->stackbuf[(ulong)(STACK_OFFSET_TYPE(OFF))])))
|
|
--
|
|
2.37.1
|
|
|