Re: [Valgrind-users] valgrind hang on start phase - 2

[Philippe W. <phi...@sk...>]

On Fri, 2012-08-17 at 12:29 -0700, John Reiser wrote:
> > http://pastebin.com/n60pN1LL
> 
> The line
> 
>    SYSCALL[11763,1](  0) sys_read ( 4, 0x90b2e34, 38346752 )
> 
> appears many many times.  A read() of 38MB is done over and over and over again.
> That's expensive.  A read()-from-a-device is a write-to-memory,
> so memcheck must mark those 38MB as valid, over and over and over again.

I am not sure the read syscall is successful.
here are some succesful read:
SYSCALL[11763,1](  0) sys_read ( 4, 0x7fee9a740, 1458176 ) --> [async] ... 
SYSCALL[11763,1](  0) ... [async] --> Success(0x0:0x164000) 

but then a bunch of lines like:
SYSCALL[11763,1](  0) sys_read ( 4, 0x90b2e34, 38346752 ) --> [async] ... 
SYSCALL[11763,1]( 15) sys_rt_sigreturn ( ) --> [pre-success] NoWriteResult 

without indication of successful result.
It is not very clear to what is happening.

If you run the same thing with 3.8.0, when it hangs,
you might take a look with vgdb at what your application is doing,
either from the command line:
   vgdb  v.info scheduler
or in gdb:
  gdb
  target remote | vgdb
  ... and then backtrace and similar

Alternatively, using -v -v -v -d -d -d --trace-syscalls=yes --trace-signals=yes
might give some more lights.

Philippe

Philippe