Re: [LTP] Patch to record kernel dump message to each testcases log

Garrett Cooper
2010-10-13T04:58:13Z

On Tue, Oct 12, 2010 at 9:38 PM, hake huang <hakehuang@gmail.com> wrote:
> Hi
>
> I see this simple solution is no quite fit. But the kernel dump message for
> each test case is necessary for analysing. I can work on this further, with
> below help:
> 1. Where can I find the reason for the IIRC break?

IIRC -> If I remember correctly.

> 2. Can it  be an option to avoid the size limitation on some embedded
> system?

No. This is outside the realm of LTP, but we must remain conscious of
the fact that there are folks running LTP on cellphones, etc, where
space is very much a luxury.

> 3.  A kind of seperating tag is needed for kernel message, right? e.g
> <kernel_dump_start>dump message<kernel_dump_end>

I think that adding an optional capture feature might be worthwhile,
but you'll no doubt quickly find with some processes that the dmesg
buffer will fill up quickly.

> 4.  I see in ltp-pan.c the file descriptors, terminals are changed in child
> process. if the system(3) has problem, the worst cases is there are no
> kernel messge output in parent process, but the pan can still function well.

Can you say that with 100% certainty? One of the potential problems
with system is the fact that it allocates a shell and depending on how
processes are executed and how file descriptors are cleaned up,

Actually, pan makes zero attempts at closing open file descriptors and
the like, so the problem is still very much with pan.

> if not use system(3), can you give your suggestion on this, exec(3) seems to
> have the same problem as system(3)?

Yes and no. In this case the problems that exist with open file
descriptor inheritance, etc are unfortunately no worse from that
perspective than your proposed code would do, but there are still
other problems that need to be resolved with your proposed change
anyhow that are much more pressing.

-Garrett