[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20071009013011.GV8181@ftp.linux.org.uk>
Date: Tue, 9 Oct 2007 02:30:11 +0100
From: Al Viro <viro@....linux.org.uk>
To: Tim Pepper <lnxninja@...ux.vnet.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] lockdep: Avoid /proc/lockdep & lock_stat infinite output
On Mon, Oct 08, 2007 at 06:15:51PM -0700, Tim Pepper wrote:
>
> When a read() requests an amount of data smaller than the amount of data
> that the seq_file's foo_show() outputs, the output starts looping and
> outputs the "stuck" element's data infinitely. There may be multiple
> sequential calls to foo_start(), foo_next()/foo_show(), and foo_stop()
> for a single open with sequential read of the file. The _start() does not
> have to start with the 0th element and _show() might be called multiple
> times in a row for the same element for a given open/read of the seq_file.
>
> static void *l_start(struct seq_file *m, loff_t *pos)
> {
> - struct lock_class *class = m->private;
> + struct lock_class *class;
> + loff_t i = 0;
>
> - if (&class->lock_entry == all_lock_classes.next)
> + if (*pos == 0)
> seq_printf(m, "all lock classes:\n");
Do not generate output outside of ->show() and you won't have these
problems. That's where your infinite output crap comes from.
IOW, NAK - fix the underlying problem.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists