linux-kernel - Re: [PATCH] nbd: ratelimit error msgs after socket close

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 2 Feb 2016 12:07:04 -0500
From:	Dan Streetman <dan.streetman@...onical.com>
To:	Markus Pargmann <mpa@...gutronix.de>, Jens Axboe <axboe@...com>
Cc:	nbd-general@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
	Dan Streetman <ddstreet@...e.org>,
	Dan Streetman <dan.streetman@...onical.com>
Subject: Re: [PATCH] nbd: ratelimit error msgs after socket close

Hi Markus,

just checking if you had any comments on this patch?

On Thu, Jan 14, 2016 at 1:42 PM, Dan Streetman
<dan.streetman@...onical.com> wrote:
> Make the "Attempted send on closed socket" error messages generated in
> nbd_request_handler() ratelimited.
>
> When the nbd socket is shutdown, the nbd_request_handler() function emits
> an error message for every request remaining in its queue.  If the queue
> is large, this will spam a large amount of messages to the log.  There's
> no need for a separate error message for each request, so this patch
> ratelimits it.
>
> In the specific case this was found, the system was virtual and the error
> messages were logged to the serial port, which overwhelmed it.
>
> Fixes: 4d48a542b427 ("nbd: fix I/O hang on disconnected nbds")
> Signed-off-by: Dan Streetman <dan.streetman@...onical.com>
> ---
>  drivers/block/nbd.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index e4c5cc1..c65d41f 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -618,8 +618,8 @@ static void nbd_request_handler(struct request_queue *q)
>                         req, req->cmd_type);
>
>                 if (unlikely(!nbd->sock)) {
> -                       dev_err(disk_to_dev(nbd->disk),
> -                               "Attempted send on closed socket\n");
> +                       dev_err_ratelimited(disk_to_dev(nbd->disk),
> +                                           "Attempted send on closed socket\n");
>                         req->errors++;
>                         nbd_end_request(nbd, req);
>                         spin_lock_irq(q->queue_lock);
> --
> 2.5.0
>