Re: 2.5.51 nanosleep fails

[Jim Houston]

Marco d'Itri wrote:
> nanosleep fails after being interrupted:
>
> [...]
> nanosleep({1, 0},
> [1]+  Stopped                 strace tail -f /var/log/uucp/Log
> md@wonderland:~$ fg
> strace tail -f /var/log/uucp/Log
>  <unfinished ...>
> --- SIGCONT (Continued) ---
> <... nanosleep resumed> 0)              = -1 ENOSYS (Function not implemented)>
>
> This can be reliably reproduced.                                              

Hi Marco, Everyone,

I was able to reproduce this issue.  It happens on all the
kernels I tried including a stock Redhat kernel.  This is just 
an idiosyncrasy of strace. In this case both the strace and
tail are sent a SIGTSTP when they are put into the background.
Its not suprising that this might confuse strace.

I also tried this with a program which just does a long
nanosleep.  Strace still shows a return of ENOSYS but the
program actually gets the correct EINTR.

Jim Houston - Concurrent Computer Corp.