All of lore.kernel.org
 help / color / mirror / Atom feed
From: Wang Kai <morgan.wang@huawei.com>
To: <rmk+kernel@arm.linux.org.uk>, <k.khlebnikov@samsung.com>
Cc: <linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>, <wangnan0@huawei.com>,
	<kernel.openeuler@huawei.com>
Subject: [PATCH] ARM:stacktrace: make stacktrace skip always right.
Date: Thu, 11 Sep 2014 17:02:23 +0800	[thread overview]
Message-ID: <1410426143-9455-1-git-send-email-morgan.wang@huawei.com> (raw)

This patch is for commit 3683f44c42e991d313dc301504ee0fca1aeb8580,
that makes stacktrace NOT begin from stacktrace self function,
which are: __save_stack_trace and save_stack_trace.

But save_stack_trace will NOT have stacktrace information when build
with '-O2', assemble code looks like below:
   00000154 <save_stack_trace>:
    154:   e1a0200d        mov     r2, sp
    158:   e1a01000        mov     r1, r0
    15c:   e3c23d7f        bic     r3, r2, #8128   ; 0x1fc0
    160:   e3a02000        mov     r2, #0
    164:   e3c3303f        bic     r3, r3, #63     ; 0x3f
    168:   e593000c        ldr     r0, [r3, #12]
    16c:   eaffffd0        b       b4 <__save_stack_trace>

In this situation, the "data.skip +=2" operation will skip the last
user call function, make user stacktrace strange/incorrect.

To fix this, we have to make sure save_stack_trace has stacktrace info,
then skip 2 function will be OK.

Signed-off-by: Wang Kai <morgan.wang@huawei.com>
---
 arch/arm/kernel/stacktrace.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
index 6582c4a..1eb1b5ae 100644
--- a/arch/arm/kernel/stacktrace.c
+++ b/arch/arm/kernel/stacktrace.c
@@ -134,6 +134,7 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
 void save_stack_trace(struct stack_trace *trace)
 {
 	__save_stack_trace(current, trace, 0);
+	asm volatile("" : : : "memory");
 }
 EXPORT_SYMBOL_GPL(save_stack_trace);
 #endif
-- 
1.8.5.5


WARNING: multiple messages have this Message-ID (diff)
From: morgan.wang@huawei.com (Wang Kai)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM:stacktrace: make stacktrace skip always right.
Date: Thu, 11 Sep 2014 17:02:23 +0800	[thread overview]
Message-ID: <1410426143-9455-1-git-send-email-morgan.wang@huawei.com> (raw)

This patch is for commit 3683f44c42e991d313dc301504ee0fca1aeb8580,
that makes stacktrace NOT begin from stacktrace self function,
which are: __save_stack_trace and save_stack_trace.

But save_stack_trace will NOT have stacktrace information when build
with '-O2', assemble code looks like below:
   00000154 <save_stack_trace>:
    154:   e1a0200d        mov     r2, sp
    158:   e1a01000        mov     r1, r0
    15c:   e3c23d7f        bic     r3, r2, #8128   ; 0x1fc0
    160:   e3a02000        mov     r2, #0
    164:   e3c3303f        bic     r3, r3, #63     ; 0x3f
    168:   e593000c        ldr     r0, [r3, #12]
    16c:   eaffffd0        b       b4 <__save_stack_trace>

In this situation, the "data.skip +=2" operation will skip the last
user call function, make user stacktrace strange/incorrect.

To fix this, we have to make sure save_stack_trace has stacktrace info,
then skip 2 function will be OK.

Signed-off-by: Wang Kai <morgan.wang@huawei.com>
---
 arch/arm/kernel/stacktrace.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
index 6582c4a..1eb1b5ae 100644
--- a/arch/arm/kernel/stacktrace.c
+++ b/arch/arm/kernel/stacktrace.c
@@ -134,6 +134,7 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
 void save_stack_trace(struct stack_trace *trace)
 {
 	__save_stack_trace(current, trace, 0);
+	asm volatile("" : : : "memory");
 }
 EXPORT_SYMBOL_GPL(save_stack_trace);
 #endif
-- 
1.8.5.5

             reply	other threads:[~2014-09-11  9:14 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-11  9:02 Wang Kai [this message]
2014-09-11  9:02 ` [PATCH] ARM:stacktrace: make stacktrace skip always right Wang Kai

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1410426143-9455-1-git-send-email-morgan.wang@huawei.com \
    --to=morgan.wang@huawei.com \
    --cc=k.khlebnikov@samsung.com \
    --cc=kernel.openeuler@huawei.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=rmk+kernel@arm.linux.org.uk \
    --cc=wangnan0@huawei.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.