Re: BUG: NTPL: waitpid() doesn't return?

From: Roland McGrath (roland_at_redhat.com)
Date: 01/31/04

  • Next message: Willem Riede: "Re: The survival of ide-scsi in 2.6.x [PATCH 3/3]" 
    Date:	Sat, 31 Jan 2004 13:52:43 -0800
To: "Matthias Urlichs" <smurf@smurf.noris.de>

    > Your test program works... except that it reports, when I strace it,
    >
    > [pid 10629] waitpid(10631, Process 10629 suspended
    > <unfinished ...>
    > [pid 10628] <... mmap2 resumed> ) = 0x41966000
    > [pid 10630] waitpid(10632, Process 10630 suspended
    > <unfinished ...>
    >
    > Those "Process ### suspended" messages did NOT happen with the Python
    > script that exhibits the bug.

    This is an strace bug. Because of goofy ptrace interactions, strace does
    funny business with threads doing wait calls. strace should resume those
    threads when the pids they are waiting for exit.

    Make sure you are using the most current strace and if it's still not
    different then report the strace bug (<strace-devel@lists.sourceforge.net>
    or https://bugzilla.redhat.com are fine).
      
    To research the issue thoroughly, you may have to avoid relying on strace
    to tell you what calls your programs make.
    -
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