Messages in this thread |  | | | Date | Mon, 5 Oct 2009 13:47:39 +0200 (CEST) | | From | Thomas Gleixner <> | | Subject | Re: futex question |
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On Mon, 5 Oct 2009, Peter Zijlstra wrote: > On Mon, 2009-10-05 at 12:56 +0200, Thomas Gleixner wrote: > > > > Looking more into that I think we should check whether the robust list > > has an entry (lock held) in do_execve() and return -EWOULDBLOCK to > > luser space. Same if pi_waiters is not empty. Holding a lock and > > calling execve() is simply broken. > > Fine by me ;-) > > something like the below? > > The question is of course what Ani was doing that triggered this in the > first place and if he can live with this.. :-) > > --- > fs/exec.c | 16 ++++++++++++++++ > 1 files changed, 16 insertions(+), 0 deletions(-) > > diff --git a/fs/exec.c b/fs/exec.c > index d49be6b..0812ba6 100644 > --- a/fs/exec.c > +++ b/fs/exec.c > @@ -1295,6 +1295,22 @@ int do_execve(char * filename, > bool clear_in_exec; > int retval; > > + retval = -EWOULDBLOCK; > +#ifdef CONFIG_FUTEX > + if (unlikely(current->robust_list)) > + goto out_ret; > +#ifdef CONFIG_COMPAT > + if (unlikely(current->compat_robust_list)) > + goto out_ret; > +#endif
That needs to call into the futex code and check whether the list is empty. If not empty, return. If empty set the pointer to NULL
Thanks,
tglx
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