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SubjectRe: [2.6.28-rc1 regression] wmifinfo dockapp takes 100% of cpu (bisected)
On Sat 25.Oct'08 at 20:03:27 +0200, Marcin Slusarz wrote:
> On Sat, Oct 25, 2008 at 06:25:05PM +0200, Carlos R. Mafra wrote:
> > On Sat 25.Oct'08 at 7:13:48 -0700, Arjan van de Ven wrote:
> > > On Sat, 25 Oct 2008 07:05:42 -0700
> > > Arjan van de Ven <arjan@linux.intel.com> wrote:
> > >
> > > > Carlos R. Mafra wrote:
> > > >
> > > >
> > > > Hi,
> > > >
> > > > the line below is the key one:
> > > >
> > > > > select(4, [3], NULL, NULL, {0, 5000000}) = -1 EINVAL (Invalid
> > > > > argument)
> > > >
> > > > the application gives us an invalid timeval; it should have been (5,
> > > > 0) However, if the kernel accepted this before the kernel needs to
> > > > now also accept it obviously, I'll look into it
> > >
> > > This patch should fix it; I'm a bit worried that I need to fix up
> > > userlands "mess", but ok. I also checked all other converted functions,
> > > and only select has this problem. The problem is that the conversion
> > > from microseconds to nanoseconds is overflowing ;-(
> > >
> > > can you give this one a test?
> >
> > Your patch did not solve it.
> >
> > But you are right that the program I use is a mess, it was doing
> >
> > tv.tv_sec = 0;
> > tv.tv_usec = 5000000L;
> >
> > So I changed it to
> >
> > tv.tv_sec = 5;
> > tv.tv_usec = 0;
> >
> > and it worked (with and without your patch).
> >
> > From what I understand this is what your patch does,
> > so it is strange that it didn't work...
> >
> > > diff --git a/fs/compat.c b/fs/compat.c
> > > index fe3c9bf..95ceee6 100644
> > > --- a/fs/compat.c
> > > +++ b/fs/compat.c
> > > @@ -1680,9 +1680,16 @@ asmlinkage long compat_sys_select(int n, compat_ulong_t __user *inp,
> > > int ret;
> > >
> > > if (tvp) {
> > > + int i;
> > > if (copy_from_user(&tv, tvp, sizeof(tv)))
> > > return -EFAULT;
> > >
> > > + while (tv.tv_usec > USEC_PER_SEC && i < 1000) {
> ^
> should be >=
>
> > > + i++;
> > > + tv.tv_sec ++;
> > > + tv.tv_usec -= USEC_PER_SEC;
> > > + }
> > > +
> > > to = &end_time;
> > > if (poll_select_set_timeout(to, tv.tv_sec,
> > > tv.tv_usec * NSEC_PER_USEC))
> > > diff --git a/fs/select.c b/fs/select.c
> > > index 448e440..e4e7cdb 100644
> > > --- a/fs/select.c
> > > +++ b/fs/select.c
> > > @@ -515,9 +515,16 @@ asmlinkage long sys_select(int n, fd_set __user *inp, fd_set __user *outp,
> > > int ret;
> > >
> > > if (tvp) {
> > > + int i = 0;
> > > if (copy_from_user(&tv, tvp, sizeof(tv)))
> > > return -EFAULT;
> > >
> > > + while (tv.tv_usec > USEC_PER_SEC && i < 1000) {
>
> and here too


Yes, changing to >= solves the problem here.

Thanks Arjan and Marcin!


> > > + i++;
> > > + tv.tv_sec ++;
> > > + tv.tv_usec -= USEC_PER_SEC;
> > > + }
> > > +
> > > to = &end_time;
> > > if (poll_select_set_timeout(to, tv.tv_sec,
> > > tv.tv_usec * NSEC_PER_USEC))
> > >
> > > --


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