Re: [PATCH stable-3.0] ptrace: don't clear GROUP_STOP_SIGMASK ondouble-stop

From: Greg KH
Date: Mon Sep 26 2011 - 18:15:37 EST


On Mon, Sep 26, 2011 at 07:06:32PM +0200, Oleg Nesterov wrote:
> https://bugzilla.redhat.com/show_bug.cgi?id=740121
>
> 1. Luke Macken triggered WARN_ON(!(group_stop & GROUP_STOP_SIGMASK))
> in do_signal_stop().
>
> This is because do_signal_stop() clears GROUP_STOP_SIGMASK part
> unconditionally but doesn't update it if task_is_stopped().
>
> 2. Looking at this problem I noticed that WARN_ON_ONCE(!ptrace) is
> not right, a stopped-but-resumed tracee can clone the untraced
> thread in the SIGNAL_STOP_STOPPED group, the new thread can start
> another group-stop.
>
> Remove this warning, we need more fixes to make it true.
>
> Reported-by: Luke Macken <lmacken@xxxxxxxxxx>
> Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>

Is this fix in Linus's tree already? If so, what's the git commit id?

If not, please take a look at Documentation/stable_kernel_rules.txt for
how to properly submit a patch to the stable tree.

thanks,

greg k-h
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