Kernel analysis utility for live systems, netdump, diskdump, kdump, LKCD or mcore dumpfiles
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2.1 KiB

From 1706f8b6ab50cd25e8fdabe8d50a37ce89bd60e0 Mon Sep 17 00:00:00 2001
From: Lianbo Jiang <lijiang@redhat.com>
Date: Thu, 6 Jan 2022 12:01:17 +0800
Subject: [PATCH 04/11] Fix for "bt -v" option to display the stack-end address
correctly
The "bt -v" command prints incorrect stack-end address when the
"CONFIG_THREAD_INFO_IN_TASK=y" is enabled in kernel, the "bt -v"
command output shows that the value stored at 0xffff8dee0312c198
is 0xffffffffc076400a, however, the value stored actually at
0xffff8dee0312c198 is NULL(0x0000000000000000), the stack-end
address is incorrect.
Without the patch:
crash> bt -v
PID: 28642 TASK: ffff8dee0312c180 CPU: 0 COMMAND: "insmod"
possible stack overflow: ffff8dee0312c198: ffffffffc076400a != STACK_END_MAGIC
^^^^^^^^^^^^^^^^
crash> rd 0xffff8dee0312c198
ffff8dee0312c198: 0000000000000000 ........
^^^^^^^^^^^^^^^^
With the patch:
crash> bt -v
PID: 28642 TASK: ffff8dee0312c180 CPU: 0 COMMAND: "insmod"
possible stack overflow: ffff991340bc0000: ffffffffc076400a != STACK_END_MAGIC
crash> rd 0xffff991340bc0000
ffff991340bc0000: ffffffffc076400a .@v.....
Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
---
task.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/task.c b/task.c
index bb6a5da8ad33..b5ddc88e0acb 100644
--- a/task.c
+++ b/task.c
@@ -11202,7 +11202,7 @@ check_stack_overflow(void)
{
int i, overflow, cpu_size, cpu, total;
char buf[BUFSIZE];
- ulong magic, task, stackbase;
+ ulong magic, task, stackbase, location;
struct task_context *tc;
if (!tt->stack_end_magic &&
@@ -11286,9 +11286,15 @@ check_stack_end_magic:
if (magic != STACK_END_MAGIC) {
if (!overflow)
print_task_header(fp, tc, 0);
+
+ if (tt->flags & THREAD_INFO_IN_TASK)
+ location = task_to_stackbase(tc->task);
+ else
+ location = tc->thread_info + SIZE(thread_info);
+
fprintf(fp,
" possible stack overflow: %lx: %lx != STACK_END_MAGIC\n",
- tc->thread_info + SIZE(thread_info), magic);
+ location, magic);
overflow++, total++;
}
--
2.20.1