From: Al Viro <viro@ZenIV.linux.org.uk>
To: Dave Jones <davej@codemonkey.org.uk>,
Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: iov_iter_pipe warning.
Date: Thu, 27 Apr 2017 18:39:43 +0100 [thread overview]
Message-ID: <20170427173943.GD29622@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20170427163444.6pbuyhgasydvtj24@codemonkey.org.uk>
On Thu, Apr 27, 2017 at 12:34:44PM -0400, Dave Jones wrote:
> [977286.117268] RPC request reserved 116 but used 268
> [1918138.126285] RPC request reserved 200 but used 268
> [2327777.483077] RPC request reserved 200 but used 268
> [2327800.909007] RPC request reserved 200 but used 268
>
> related ?
Rather unlikely... AFAICS, that's nfsd miscalculating the response
size and generating longer response than it has reserved. The warning
comes from svc_xprt_release(). Out of its callers, svc_recv() is
impossible (it zeroes rqstp->rq_res.len before calling the sucker, so
there's no way for it to be found too large), which leaves svc_drop()
and svc_send(). The last one is more likely, AFAICS, and there the
length is calculated by
/* calculate over-all length */
xb = &rqstp->rq_res;
xb->len = xb->head[0].iov_len +
xb->page_len +
xb->tail[0].iov_len;
Might be interesting to slap WARN_ON(xb->len > rqstp->rq_reserved); there
and see if it triggers. Or something like
if (WARN_ON(rqstp->rq_res->head[0].iov_len +
rqstp->rq_res->page_len +
rqstp->rq_res->tail[0].iov_len > rqstp->rq_reserved) {
try to print something useful about request and response
}
right before the call of ->xpo_release_rqst() in there - I hadn't looked
at that code for a long time, but it smells like dumping the request is
better done before the skbs containing it get dropped...
next prev parent reply other threads:[~2017-04-27 17:40 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-21 20:59 iov_iter_pipe warning Dave Jones
2017-04-05 22:02 ` Dave Jones
2017-04-10 19:28 ` Al Viro
2017-04-10 19:42 ` Dave Jones
2017-04-10 19:57 ` Al Viro
2017-04-10 23:48 ` Dave Jones
2017-04-11 0:22 ` Al Viro
2017-04-11 3:05 ` Dave Jones
2017-04-11 3:28 ` Al Viro
2017-04-11 20:53 ` Dave Jones
2017-04-11 21:12 ` Al Viro
2017-04-11 22:25 ` Dave Jones
2017-04-11 23:28 ` Al Viro
2017-04-11 23:34 ` Dave Jones
2017-04-11 23:48 ` Al Viro
2017-04-11 23:45 ` Dave Jones
2017-04-11 23:51 ` Al Viro
2017-04-11 23:56 ` Al Viro
2017-04-12 0:06 ` Dave Jones
2017-04-12 0:17 ` Al Viro
2017-04-12 0:58 ` Dave Jones
2017-04-12 1:15 ` Al Viro
2017-04-12 2:29 ` Dave Jones
2017-04-12 2:58 ` Al Viro
2017-04-12 14:35 ` Dave Jones
2017-04-12 15:26 ` Al Viro
2017-04-12 16:27 ` Dave Jones
2017-04-12 17:07 ` Al Viro
2017-04-12 19:03 ` Dave Jones
2017-04-21 17:54 ` Al Viro
2017-04-27 4:19 ` Dave Jones
2017-04-27 16:34 ` Dave Jones
2017-04-27 17:39 ` Al Viro [this message]
2017-04-28 15:29 ` Dave Jones
2017-04-28 16:43 ` Al Viro
2017-04-28 16:50 ` Dave Jones
2017-04-28 17:20 ` Al Viro
2017-04-28 18:25 ` Al Viro
2017-04-29 1:58 ` Dave Jones
2017-04-29 2:47 ` Al Viro
2017-04-29 15:51 ` Dave Jones
2017-04-29 20:46 ` [git pull] vfs.git fix (Re: iov_iter_pipe warning.) Al Viro
2017-08-07 20:18 ` iov_iter_pipe warning Dave Jones
2017-08-28 20:31 ` Dave Jones
2017-08-29 4:25 ` Darrick J. Wong
2017-08-30 17:05 ` Dave Jones
2017-08-30 17:13 ` Darrick J. Wong
2017-08-30 17:17 ` Dave Jones
2017-09-06 20:03 ` Dave Jones
2017-09-06 23:46 ` Dave Chinner
2017-09-07 3:48 ` Dave Jones
2017-09-07 4:33 ` Al Viro
2017-09-08 1:04 ` Al Viro
2017-09-10 1:07 ` Dave Jones
2017-09-10 2:57 ` Al Viro
2017-09-10 16:07 ` Dave Jones
2017-09-10 20:05 ` Al Viro
2017-09-10 20:07 ` Dave Jones
2017-09-10 20:33 ` Al Viro
2017-09-10 21:11 ` Dave Chinner
2017-09-10 21:19 ` Al Viro
2017-09-10 22:08 ` Dave Chinner
2017-09-10 23:07 ` Al Viro
2017-09-10 23:15 ` Al Viro
2017-09-11 0:31 ` Dave Chinner
2017-09-11 3:32 ` Al Viro
2017-09-11 6:44 ` Dave Chinner
2017-09-11 20:07 ` Al Viro
2017-09-11 20:17 ` Al Viro
2017-09-12 6:02 ` Dave Chinner
2017-09-12 11:13 ` Al Viro
2017-09-11 12:07 ` Christoph Hellwig
2017-09-11 12:51 ` Al Viro
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20170427173943.GD29622@ZenIV.linux.org.uk \
--to=viro@zeniv.linux.org.uk \
--cc=davej@codemonkey.org.uk \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).