Review request: 7003789 PTRACE_GETREGS problems with SA on Linux.
Yasumasa Suenaga
suenaga.yasumasa at oss.ntt.co.jp
Thu Dec 2 22:21:02 PST 2010
Hi David, Kevin,
> #if defined(PTRACE_GETREGS) || defined(PT_GETREGS)
> #define PTRACE_GETREGS_REQ PTRACE_GETREGS
> #endif
If PTRACE_GETREGS is undefined and PT_GETREGS is defined, PTRACE_GETREGS_REQ will be defined
by undefined value. (PTRACE_GETREGS: 1? decided by preprocessor... does that case exist?)
In Linux manpage PTRACE(2) in Fedora14, PTRACE_GETREGS is described, PTRACE_GETREGS64 and
PT_GETREGS is NOT described.
My system(Fedora14 x86_64) defines PTRACE_GETREGS and PT_GETREGS, PTRACE_GETREGS64 does NOT define.
So, how about this?
-------
#if defined(_LP64) && defined(PTRACE_GETREGS64) /* for SPARCV9(and others?) */
#define PTRACE_GETREGS_REQ PTRACE_GETREGS64
#elif defined(PTRACE_GETREGS) /* for Linux */
#define PTRACE_GETREGS_REQ PTRACE_GETREGS
#elif defined(PT_GETREGS) /* last resort */
#define PTRACE_GETREGS_REQ PT_GETREGS
#endif /* _LP64 */
-------
BTW, this modification is for "agent/src/os/linux/ps_proc.c".
I guess that this source affects for Linux ONLY.
If my guess is correct, we can delete the statement about SPARC from this source code.
-------
#if defined(sparc) || defined(sparcv9)
#define ptrace_getregs(request, pid, addr, data) ptrace(request, pid, addr, data)
#else
#define ptrace_getregs(request, pid, addr, data) ptrace(request, pid, data, addr)
#endif
-------
and
-------
#ifdef PTRACE_GETREGS64
#define PTRACE_GETREGS_REQ PTRACE_GETREGS64
-------
Thanks.
Yasumasa
(2010/12/03 12:23), David Holmes wrote:
> Kevin Walls said the following on 12/03/10 06:03:
>> Thanks both for pointing out that I didn't notice I was smashing the
>> 32-bit case. 8-)
>>
>> I can now build and test 32 and 64-bit OK with...
>>
>> #ifdef _LP64
>> #ifdef PTRACE_GETREGS64
>> #define PTRACE_GETREGS_REQ PTRACE_GETREGS64
>> #elif defined(PTRACE_GETREGS)
>> #define PTRACE_GETREGS_REQ PTRACE_GETREGS
>> #elif defined(PT_GETREGS)
>> #define PTRACE_GETREGS_REQ PT_GETREGS
>> #endif
>> #else
>> #if defined(PTRACE_GETREGS) || defined(PT_GETREGS)
>> #define PTRACE_GETREGS_REQ PTRACE_GETREGS
>> #endif
>> #endif /* _LP64 */
>>
>> My 64-bit system is Fedora and really needs to use PT_REGS as that's the
>> only definition. My 32-bit system is a different RedHat and has
>> PTRACE_GETREGS defined so the 32-bit build does work. Am tempted to
>> change the 32-bit side of the ifdef to also use PT_GETREGS as a last
>> resort...
>
> I'd be tempted to do that too. This seems so inconsistent I wouldn't
> trust what you might find on any particular linux.
>
> If we knew that we'd never find PTRACE_GETREGS64 on a 32-bit system we
> could make it somewhat simpler.
>
> David
>
>> Thanks
>> Kevin
>>
>>
>> On 02/12/2010 02:23, Yasumasa Suenaga wrote:
>>> Thank you for the reply.
>>>
>>> I've read your patch on a webrev.
>>> Your patch will work on AMD64 architecture.
>>> However, this patch will not work on x86 (32bit) architecture.
>>> Preprocessor in GCC for i386 does not define "_LP64" .
>>>
>>> -----------------
>>> [root at RHEL4-4 test]# cat /etc/redhat-release
>>> Red Hat Enterprise Linux ES release 4 (Nahant Update 4)
>>> [root at RHEL4-4 test]# uname -a
>>> Linux RHEL4-4 2.6.9-42.EL #1 Wed Jul 12 23:16:43 EDT 2006 i686 i686 i386 GNU/Linux
>>> [root at RHEL4-4 test]# rpm -q glibc
>>> glibc-2.3.4-2.25
>>> [root at RHEL4-4 test]# rpm -q gcc
>>> gcc-3.4.6-3
>>> [root at RHEL4-4 test]# touch test.h
>>> [root at RHEL4-4 test]# cpp -dM test.h | grep _LP64
>>> [root at RHEL4-4 test]#
>>> -----------------
>>>
>>>
>>> So, you need to modify the patch as follows:
>>>
>>> -----------------
>>> [root at Fedora13 OpenJDK7]# diff -u b118/openjdk/hotspot/agent/src/os/linux/ps_proc.c trunk/
>>> openjdk/hotspot/agent/src/os/linux/ps_proc.c
>>> --- a/agent/src/os/linux/ps_proc.c 2010-11-12 05:43:12.000000000 +0900
>>> +++ b/agent/src/os/linux/ps_proc.c 2010-12-02 10:45:09.117050388 +0900
>>> @@ -124,6 +124,8 @@
>>> #ifdef _LP64
>>> #ifdef PTRACE_GETREGS64
>>> #define PTRACE_GETREGS_REQ PTRACE_GETREGS64
>>> +#elif defined(PTRACE_GETREGS)
>>> +#define PTRACE_GETREGS_REQ PTRACE_GETREGS
>>> #endif
>>> #else
>>> #if defined(PTRACE_GETREGS) || defined(PT_GETREGS)
>>> -----------------
>>>
>>>
>>> Thanks.
>>>
>>>
>>> (2010/12/02 1:41), Kevin Walls wrote:
>>>> Sorry, there was actually a typo in that diff, although it was good
>>>> enough to be a solution on my system.
>>>>
>>>> A webrev also:
>>>>
>>>> http://cr.openjdk.java.net/~kevinw/7003789/webrev.00/
>>>>
>>>> Thanks
>>>> Kevin
>>>>
>>>>
>>>> On 01/12/2010 16:01, Kevin Walls wrote:
>>>>> Hi --
>>>>>
>>>>> I've just been hitting that as well.... I think it needs to be dealt
>>>>> with as a separate bug as there may be a few which are similar - and
>>>>> 6359295 is marked fixed in 5.0 long ago...
>>>>>
>>>>> I just found your message after I'd done some investigating... The patch
>>>>> I was working with is to split one of the existing "if defined"
>>>>> statements, as currently the bug is: if we have PT_GETREGS defined, we
>>>>> use PTRACE_GETREGS to define PTRACE_GETREGS_REQ... We soon realise that
>>>>> may NOT be defined and give the "unsupported" message. So I can log and
>>>>> bug and get this done if it sounds good:
>>>>>
>>>>> [kevin at oldbox make]$ hg diff ../src/os/linux/ps_proc.c
>>>>> diff --git a/agent/src/os/linux/ps_proc.c b/agent/src/os/linux/ps_proc.c
>>>>> --- a/agent/src/os/linux/ps_proc.c
>>>>> +++ b/agent/src/os/linux/ps_proc.c
>>>>> @@ -124,9 +124,9 @@
>>>>> #ifdef _LP64
>>>>> #ifdef PTRACE_GETREGS64
>>>>> #define PTRACE_GETREGS_REQ PTRACE_GETREGS64
>>>>> -#endif
>>>>> -#else
>>>>> -#if defined(PTRACE_GETREGS) || defined(PT_GETREGS)
>>>>> +#elif defined(PTRACE_GETREGS)
>>>>> +#define PTRACE_GETREGS_REQ PTRACE_GETREGS
>>>>> +#elif defined (PT_GETREGS)
>>>>> #define PTRACE_GETREGS_REQ PTRACE_GETREGS
>>>>> #endif
>>>>> #endif /* _LP64 */
>>>>>
>>>>>
>>>>>
>>>>> Regards
>>>>> Kevin
>>>>>
>>>>>
>>>>>
>>>>> On 15/11/2010 06:46, Yasumasa Suenaga wrote:
>>>>>> Hi.
>>>>>>
>>>>>> I and co-worker use jstack for various trouble shooting.
>>>>>>
>>>>>> We mainly use Java on Linux with AMD64 architecture.
>>>>>> However, jstack -F option doesn't work our platform.
>>>>>>
>>>>>> I ran jstack -F with LIBSAPROC_DEBUG=1 (environment variable),
>>>>>> I got following messages:
>>>>>>
>>>>>>
>>>>>> /***************/
>>>>>> Thread 31933: (state = BLOCKED)
>>>>>> libsaproc DEBUG: ptrace(PTRACE_GETREGS, ...) not supported
>>>>>> Error occurred during stack walking:
>>>>>> sun.jvm.hotspot.debugger.DebuggerException: sun.jvm.hotspot.debugger.DebuggerException: get_thread_regs failed for a lwp
>>>>>> /***************/
>>>>>>
>>>>>>
>>>>>> In order to fix this problem, I made a patch for preprocessor
>>>>>> macro in "agent/src/os/linux/ps_proc.c" .
>>>>>> The patch that attached this mail works well on Fedora 13 x86_64.
>>>>>>
>>>>>> Please merge this patch if you don't fix this problem yet.
>>>>>>
>>>>>>
>>>>>> Best regards.
>>>>>>
>>>>>>
>>
--
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