svn commit: r314813 - head/sys/kern

[Hiren Panchasara]

On 03/06/17 at 07:08P, Ngie Cooper (yaneurabeya) wrote:
> 
> > On Mar 6, 2017, at 16:20, Hiren Panchasara <hiren at FreeBSD.org> wrote:
> > 
> > Author: hiren
> > Date: Tue Mar  7 00:20:01 2017
> > New Revision: 314813
> > URL: https://svnweb.freebsd.org/changeset/base/314813
> > 
> > Log:
> >  We've found a recurring problem where some userland process would be
> >  stuck spinning at 100% cpu around sbcut_internal(). Inside
> >  sbflush_internal(), sb_ccc reached to about 4GB and before passing it
> >  to sbcut_internal(), we type-cast it from uint to int making it -ve.
> > 
> >  The root cause of sockbuf growing this large is unknown. Correct fix
> >  is also not clear but based on mailing list discussions, adding
> >  KASSERTs to panic instead of looping endlessly.
> > 
> >  Reviewed by:		glebius
> >  Sponsored by:		Limelight Networks
> > 
> > Modified:
> >  head/sys/kern/uipc_sockbuf.c
> > 
> > Modified: head/sys/kern/uipc_sockbuf.c
> > ==============================================================================
> > --- head/sys/kern/uipc_sockbuf.c	Tue Mar  7 00:13:53 2017	(r314812)
> > +++ head/sys/kern/uipc_sockbuf.c	Tue Mar  7 00:20:01 2017	(r314813)
> > @@ -1043,6 +1043,11 @@ sbcut_internal(struct sockbuf *sb, int l
> > {
> > 	struct mbuf *m, *next, *mfree;
> > 
> > +	KASSERT(len > 0, ("%s: len is %d but it is supposed to be +ve",
> > +	    __func__, len));
> > +	KASSERT(len <= sb->sb_ccc, ("%s: len: %d is > ccc: %u",
> > +	    __func__, len, sb->sb_ccc));
> > +
> > 	next = (m = sb->sb_mb) ? m->m_nextpkt : 0;
> > 	mfree = NULL;
> 
> The KASSERT is bad ? please fix it. From https://ci.freebsd.org/job/FreeBSD-head-amd64-test/1994/console :
> 
> add host 127.0.0.1panic: sbcut_internal: len is 0 but it is supposed to be +ve

Thanks, fixed in r314838.

Cheers,
Hiren
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