On Fri, Mar 17, 2006 at 06:44:21AM -0500, Chuck Ebbert wrote:
> > Specifically, the three kinds of cloning are distinguished as:
> >
> > if CLONE_VFORK -> PTRACE_EVENT_VFORK
> > else if clone exit signal == SIGCHLD -> PTRACE_EVENT_FORK
> > else PTRACE_EVENT_CLONE
> >
> > You need to do some juggling to get the actual clone flags.
>
> It might be best to leave these descriptions in terms of C library functions
> rather than kernel-internal. Looking at sys_clone() and sys_fork() I can see
> what you mean but I'm not sure how to describe it to a programmer.
Those are user accessible flags. Fork will give you a
PTRACE_EVENT_FORK, vfork will give you a PTRACE_EVENT_VFORK, but
clone may give you any of the above, depending on what arguments you
pass to it. The SIGCHLD test matches the bit described in clone(2)
for __WALL or __WCLONE, for instance.
> > BTW, I believe there are still some potential deadlocks between
> > the vfork event and the vfork done event; I used to regularly generate
> > unkillable processes working on this code.
>
> I have a test program and didn't hit any problems yet. Maybe this was fixed?
One thing that IIRC was a problem was killing the parent before the
child (or maybe the other way round) when stopped at this point - such
as would happen if you typed "kill" at a GDB prompt after catch vfork.
--
Daniel Jacobowitz
CodeSourcery
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
