Re: [PATCH 17/23] arm64: ptrace: handle ptrace_request differently for aarch32 and ilp32

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On 2016/6/25 22:15, Bamvor Zhang wrote:
Hi, Chengming

On Sat, Jun 25, 2016 at 5:36 PM, zhouchengming
<zhouchengming1@xxxxxxxxxx>  wrote:
On 2016/6/9 1:00, Yury Norov wrote:

On Wed, Jun 08, 2016 at 09:34:09AM +0800, zhouchengming wrote:

On 2016/5/24 8:04, Yury Norov wrote:

Here new aarch32 ptrace syscall handler is introsuced to avoid run-time
detection of the task type.

Signed-off-by: Yury Norov<ynorov@xxxxxxxxxxxxxxxxxx>


[...]

Hello, I found ilp32 will use sys_ptrace, not compat_sys_ptrace. So I
write
a little patch to see if can solve the problem correctly.

Thanks.

  From f6156236df578bb05c4a17e7f9776ceaf8f7afe6 Mon Sep 17 00:00:00 2001
From: Zhou Chengming<zhouchengming1@xxxxxxxxxx>
Date: Wed, 8 Jun 2016 09:46:23 +0800
Subject: [PATCH] ilp32: use compat_sys_ptrace instead of sys_ptrace

When we analyze a testcase of ptrace that failed on ilp32, we found
the syscall that the ilp32 uses is sys_ptrace, not compat_sys_ptrace.
Because in include/uapi/asm-generic/unistd.h it's defined like:
__SYSCALL(__NR_ptrace, sys_ptrace)
So we change it to __SC_COMP(__NR_ptrace, sys_ptrace, compat_sys_ptrace),
let compat tasks use the compat_sys_ptrace.

Signed-off-by: Zhou Chengming<zhouchengming1@xxxxxxxxxx>
---
   include/uapi/asm-generic/unistd.h |    2 +-
   1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/include/uapi/asm-generic/unistd.h
b/include/uapi/asm-generic/unistd.h
index 2862d2e..50ee770 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -364,7 +364,7 @@ __SC_WRAP(__NR_syslog, sys_syslog)

   /* kernel/ptrace.c */
   #define __NR_ptrace 117
-__SYSCALL(__NR_ptrace, sys_ptrace)
+__SC_COMP(__NR_ptrace, sys_ptrace, compat_sys_ptrace)

   /* kernel/sched/core.c */
   #define __NR_sched_setparam 118
--
1.7.7


Hi Zhou,

Thank you for the catch.

Could you also show the test that is failed for you. It should
probably be sent to LTP maillist.

I'm not sure your fix correct as it affects other architectures that
use standard unistd.h. I think it's better to redirect the syscall in
arch/arm64/kernel/sys_ilp32.c with corresponding definition.

Yury

.


Sorry, I missed this mail. Thanks for your reply. :)
I attach the testcase file of ptrace that failed on ilp32.
I also think it's better to redirect the syscall in ilp32, so I changed
the patch.

Thanks for your patch. But Yury has already sent an new series this week
which define ptrace to compat one.

It seems that Yury do not take GET/SETSIGMASK into account. You
could share your test case and patches at this point.

Best wishes

Bamvor

Ok, I get it. So the new series can handle ptrace correctly. :)
But as for the GET/SETSIGMASK request, both ilp32 and aarch32 are wrong, because they are handled in ptrace_request(like aarch64). But I don't have a good way to correct it in all architectures.
The architectures that use compat_ptrace_request are:
arch/arm64, arch/mips, arch/parisc, arch/powerpc, arch/s390, arch/sparc,
arch/tile, arch/x86.
We have to use two architecture dependent functions in compat_ptrace_request to fix the GET/SETSIGMASK request. (as for arch/arm64, the two functions are: put_sigset_t and get_sigset_t)
So we maybe have to prepare these functions for all these architectures.
But I don't have much time to work on it. So I just fix it for ilp32 of arch/arm64 (Ah, easier way for me). I will put my patch of this fix under Yury's new series.

Thanks!


[1] https://www.mail-archive.com/linux-doc@xxxxxxxxxxxxxxx/msg03811.html


 From 7e692ba1adf02c2a2f125836f5222f455c9ffe56 Mon Sep 17 00:00:00 2001
From: Zhou Chengming<zhouchengming1@xxxxxxxxxx>
Date: Sat, 25 Jun 2016 18:02:51 +0800
Subject: [PATCH] ilp32 should use compat_sys_ptrace

The file include/uapi/asm-generic/unistd.h defines this:
__SYSCALL(__NR_ptrace, sys_ptrace)
It may cause some ptrace tests failed on ilp32. So we redirect the ptrace
syscall in arch/arm64/kernel/sys_ilp32.c with corresponding definition.

Signed-off-by: Zhou Chengming<zhouchengming1@xxxxxxxxxx>
---
  arch/arm64/kernel/sys_ilp32.c |    3 +++
  1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/arch/arm64/kernel/sys_ilp32.c b/arch/arm64/kernel/sys_ilp32.c
index d85fe94..06d5e1b 100644
--- a/arch/arm64/kernel/sys_ilp32.c
+++ b/arch/arm64/kernel/sys_ilp32.c
@@ -46,6 +46,9 @@
  asmlinkage long ilp32_sys_rt_sigreturn_wrapper(void);
  #define compat_sys_rt_sigreturn        ilp32_sys_rt_sigreturn_wrapper

+/* ilp32 should use compat_sys_ptrace */
+#define sys_ptrace                    compat_sys_ptrace
+
  #include<asm/syscall.h>

  #undef __SYSCALL
--
1.7.7








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