Re: 2.6.24-rc5-mm1: problems with cat /proc/kpageflags

Mariusz Kozlowski
2007-12-16T18:46:48Z

> > > cat /proc/kpageflags on sparc64 causes the box to lock.
> > > I can not write on any terminal - but I can issue sysrqs and switch
> > > between consoles.
> > >
> > > cat process hangs in read(3, ...
> >
> > cat /proc/kpagecount produces similar symptoms. box is locked - sysrq-w sshd trace:
> >
> > __down
> > __down_interruptible
> > kobject_get
> > lock_kernel
> > chrdev_open
> > __dentry_open
> > nameidata_to_filp
> > open_pathname
> > do_sys_open
> > sparc32_open
> > linux_sparc_syscall32
>
> Perhaps this is related to sparsemem.
>
> Can you change line 710 of fs/proc/proc_misc.c to:
>
> ppage = NULL;

Sure.

> ..and see if it still breaks?

Yes it does - the same way as eariler. Box is locked, processes stuck in D state
and after a while "BUG: soft lockup - CPU#0 stuck for 11s!".