lists.zerezo.com



[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH] exit signals: use of uninitialized field notify_count



On Wed, 27 Aug 2008, Oleg Nesterov wrote:

* Steve VanDeBogart <vandebo-lkml@xxxxxxxxxxx> wrote:

task->signal->notify_count is only initialized if
task->signal->group_exit_task is not NULL.  Reorder a conditional so
that uninitialised memory is not used.  Found by Valgrind.

Minor comment. As Roland pointed out, it makes sense to initialize
the whole signal_struct explicitely, perhaps copy_signal() should
just use zalloc. In that case we don't need to check ->group_exit_task
at all, the same for __exit_signal().

Thanks Steve! and what do you think about the above?

It looks like that would work.  Seems that
sig->count == 0 && sig->group_exit_task != NULL can never be true.
If it does work, a lot of initialization in copy_signal() can be
removed and it would reduce the chances that a similar problem would be
reintroduced.  I would submit a patch, but I'm not sure how to trigger
those code paths in order to test it.

--
Steve
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/