On Sun, 20 May 2007 21:14:38 -0700 (PDT) Davide Libenzi <[EMAIL PROTECTED]> wrote:
> On Sun, 20 May 2007, Andrew Morton wrote: > > > If 'count' is not a multiple of sizeof(struct signalfd_siginfo)), the read() > > will return the next smallest multiple of `count'. > > > > That is, unless `count' happens to be less than 1*sizeof(struct > > signalfd_siginfo)), in which case we return -EINVAL. > > > > This seems inconsistent. > > I think it fits the rule "buffer must be big enough for at least one sigingo". > We use the special return 0; as indicator that the process we were > monitoring signals, detached the sighand. > hm. Kernel violates proper read() semantics in many places. Looks like we just did it again. > > > Also, I'm desperately hunting for the place where we zero out that local > > siginfo_t, and I ain't finding it. Someone please convince me that we're > > not leaking bits of kernel memory out to userspace in that thing. > > Hmm, __clear_user()? oic, yes, that thing. Usually we'd zero out the on-stack struct, assemble it then copy out the whole thing. I guess doing it the way you have saves a few instructions. But it's the cache hit against *uinfo which will have most of the cost, and we can't do anything about that. Unless we just remove the __clear_user() altogether. Who said that "Unused memebers should be zero"? - 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/
