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

[Bamvor Zhang]

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

[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
>
>
>



-- 
-----------------------------------------
   arm64, kernel. opensuse
   blog: http://aarch64.me
-----------------------------------------