6359295: SA utilities: "get_thread_regs failed for a lwp" from jstack(1)

[Kevin Walls]

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.
>
>