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From 0d3d80b47d69c5d303b48c0463a026e60633cae2 Mon Sep 17 00:00:00 2001
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From: Lianbo Jiang <lijiang@redhat.com>
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Date: Thu, 6 Jan 2022 12:01:17 +0800
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Subject: [PATCH 02/10] Fix for "bt -v" option to display the stack-end address
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correctly
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The "bt -v" command prints incorrect stack-end address when the
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"CONFIG_THREAD_INFO_IN_TASK=y" is enabled in kernel, the "bt -v"
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command output shows that the value stored at 0xffff8dee0312c198
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is 0xffffffffc076400a, however, the value stored actually at
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0xffff8dee0312c198 is NULL(0x0000000000000000), the stack-end
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address is incorrect.
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Without the patch:
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crash> bt -v
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PID: 28642 TASK: ffff8dee0312c180 CPU: 0 COMMAND: "insmod"
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possible stack overflow: ffff8dee0312c198: ffffffffc076400a != STACK_END_MAGIC
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^^^^^^^^^^^^^^^^
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crash> rd 0xffff8dee0312c198
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ffff8dee0312c198: 0000000000000000 ........
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^^^^^^^^^^^^^^^^
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With the patch:
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crash> bt -v
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PID: 28642 TASK: ffff8dee0312c180 CPU: 0 COMMAND: "insmod"
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possible stack overflow: ffff991340bc0000: ffffffffc076400a != STACK_END_MAGIC
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crash> rd 0xffff991340bc0000
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ffff991340bc0000: ffffffffc076400a .@v.....
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Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
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---
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task.c | 10 ++++++++--
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1 file changed, 8 insertions(+), 2 deletions(-)
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diff --git a/task.c b/task.c
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index bb6a5da8ad33..b5ddc88e0acb 100644
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--- a/task.c
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+++ b/task.c
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@@ -11202,7 +11202,7 @@ check_stack_overflow(void)
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{
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int i, overflow, cpu_size, cpu, total;
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char buf[BUFSIZE];
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- ulong magic, task, stackbase;
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+ ulong magic, task, stackbase, location;
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struct task_context *tc;
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if (!tt->stack_end_magic &&
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@@ -11286,9 +11286,15 @@ check_stack_end_magic:
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if (magic != STACK_END_MAGIC) {
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if (!overflow)
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print_task_header(fp, tc, 0);
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+
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+ if (tt->flags & THREAD_INFO_IN_TASK)
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+ location = task_to_stackbase(tc->task);
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+ else
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+ location = tc->thread_info + SIZE(thread_info);
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+
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fprintf(fp,
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" possible stack overflow: %lx: %lx != STACK_END_MAGIC\n",
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- tc->thread_info + SIZE(thread_info), magic);
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+ location, magic);
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overflow++, total++;
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}
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--
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2.20.1
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