Re: + seq_read-info-message-about-buggy-next-functions.patch added to -mm tree

[Qian Cai <cai@lca.pw>]

On Mon, 2020-03-02 at 13:20 -0500, Qian Cai wrote:
> This patch spams the console like crazy while reading sysfs,
> 
> # dmesg | grep 'buggy seq_file' | wc -l
> 4204
> 
> [ 9505.321981] LTP: starting read_all_proc (read_all -d /proc -q -r 10)
> [ 9508.222934] buggy seq_file .next function xt_match_seq_next [x_tables] did
> not updated position index
> [ 9508.223319] buggy seq_file .next function xt_match_seq_next [x_tables] did
> not updated position index
> [ 9508.223654] buggy seq_file .next function xt_match_seq_next [x_tables] did
> not updated position index
> [ 9508.223994] buggy seq_file .next function xt_match_seq_next [x_tables] did
> not updated position index
> [ 9508.224337] buggy seq_file .next function xt_match_seq_next [x_tables] did
> not updated position index
> ...
> 
> 
> > 
> > https://bugzilla.kernel.org/show_bug.cgi?id=206283
> > Link: http://lkml.kernel.org/r/244674e5-760c-86bd-d08a-047042881748@virtuozzo.com
> > Link: http://lkml.kernel.org/r/7c24087c-e280-e580-5b0c-0cdaeb14cd18@virtuozzo.com
> > Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
> > Cc: NeilBrown <neilb@suse.com>
> > Cc: Al Viro <viro@zeniv.linux.org.uk>
> > Cc: Steven Rostedt <rostedt@goodmis.org>
> > Cc: Davidlohr Bueso <dave@stgolabs.net>
> > Cc: Ingo Molnar <mingo@redhat.com>
> > Cc: Manfred Spraul <manfred@colorfullife.com>
> > Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
> > Cc: Waiman Long <longman@redhat.com>
> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> > ---
> > 
> >  fs/seq_file.c |    7 +++++--
> >  1 file changed, 5 insertions(+), 2 deletions(-)
> > 
> > --- a/fs/seq_file.c~seq_read-info-message-about-buggy-next-functions
> > +++ a/fs/seq_file.c
> > @@ -256,9 +256,12 @@ Fill:
> >  		loff_t pos = m->index;
> >  
> >  		p = m->op->next(m, p, &m->index);
> > -		if (pos == m->index)
> > -			/* Buggy ->next function */
> > +		if (pos == m->index) {
> > +			pr_info("buggy seq_file .next function %ps "
> > +				"did not updated position index\n",
> > +				m->op->next);

This?

s/pr_info/pr_info_ratelimited/

> >  			m->index++;
> > +		}
> >  		if (!p || IS_ERR(p)) {
> >  			err = PTR_ERR(p);
> >  			break;
> > _
> > 
> > Patches currently in -mm which might be from vvs@virtuozzo.com are
> > 
> > seq_read-info-message-about-buggy-next-functions.patch
> > pstore_ftrace_seq_next-should-increase-position-index.patch
> > gcov_seq_next-should-increase-position-index.patch
> > sysvipc_find_ipc-should-increase-position-index.patch
> >