LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Felix Fietkau <nbd@openwrt.org>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
	linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org,
	"John W. Linville" <linville@tuxdriver.com>
Subject: Re: Wireless regression (was 2.6.38-rc3: FUSE (sshfs) hangs under load)
Date: Fri, 04 Feb 2011 13:05:45 +0100	[thread overview]
Message-ID: <4D4BEB99.4060202@openwrt.org> (raw)
In-Reply-To: <4D4BE5D7.8090202@openwrt.org>

On 2011-02-04 12:41 PM, Felix Fietkau wrote:
> On 2011-02-04 7:49 AM, Dmitry Torokhov wrote:
>> On Thu, Feb 03, 2011 at 11:41:15AM -0800, Dmitry Torokhov wrote:
>>> On Thu, Feb 03, 2011 at 12:13:24PM +0100, Miklos Szeredi wrote:
>>> > On Wed, 2 Feb 2011, Dmitry Torokhov wrote:
>>> > > On Wed, Feb 02, 2011 at 08:52:36AM -0800, Dmitry Torokhov wrote:
>>> > > > On Wed, Feb 02, 2011 at 12:52:36PM +0100, Miklos Szeredi wrote:
>>> > > > > On Tue, 1 Feb 2011, Dmitry Torokhov wrote:
>>> > > > > > Hi,
>>> > > > > > 
>>> > > > > > After installing 2.6.38-rc3 (plus a few input patches) sshfs started to
>>> > > > > > misbehave on me under load. It starts off fine but when I try to compile
>>> > > > > > a few modules against kernel sources residing on the other box the
>>> > > > > > processes go into 'D' state and just sit there doing nothing.
>>> > > > > 
>>> > > > > Can you please post a stack trace from SysRq-T?
>>> > > > > 
>>> > > > 
>> ...
>>> > > 
>>> > > OK, so here are the stack traces you requested. First one is snapshot of
>>> > > when compile got stuck, the 2nd one is when I interrupted make which
>>> > > caused gcc to go to 'D' state.
>>> > 
>>> > There doesn't appear anything abnormal there.
>>> > 
>>> > It's going into D state after it has received an interrupt and sent it
>>> > along to the userspace filesystem.  Then it will go into
>>> > uninterruptible sleep until the answer is received.
>>> > 
>>> > So the hang is because the answer to an open request is not being
>>> > received.  I can't tell where it got stuck, apparently not anywhere on
>>> > the local machine.
>>> > 
>>> > Can you please get a log from sshfs with "-odebug,sshfs_debug" and
>>> > redirect stderr to a file?  That might tell a bit more about the
>>> > situation.  Or it might not...
>>> 
>>> Hmm, it might be just the network itself, last night mutt in ssh session
>>> froze on me as well. I guess I'll just have to finish my bisect
>>> exercise.
>>> 
>> 
>> I finished bisecting and it turned out that the problematic commit
>> happened to be in wireless (I have iwl3945):
>> 
>> commit 4cd06a344db752f513437138953af191cbe9a691
>> Author: Felix Fietkau <nbd@openwrt.org>
>> Date:   Sat Dec 18 19:30:49 2010 +0100
>> 
>>     mac80211: skip unnecessary pskb_expand_head calls
>> 
>>     If the skb is not cloned and we don't need any extra headroom, there
>>     is no point in reallocating the skb head.
>> 
>>     Signed-off-by: Felix Fietkau <nbd@openwrt.org>
>>     Signed-off-by: John W. Linville <linville@tuxdriver.com>
>> 
>> With this commit reverted from 2.6.38-rc3 I can not reproduce sshfs
>> getting stuck here.
> I really don't see how this commit could be causing these issues, and
> I'm not aware of any similar issues affecting other drivers.
Could you please try this patch to see if it fixes the issue as well?

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index ffc6749..3168eae 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1547,7 +1547,7 @@ static int ieee80211_skb_resize(struct ieee80211_local *local,
 		skb_orphan(skb);
 	}
 
-	if (skb_header_cloned(skb))
+	if (skb_cloned(skb))
 		I802_DEBUG_INC(local->tx_expand_skb_head_cloned);
 	else if (head_need || tail_need)
 		I802_DEBUG_INC(local->tx_expand_skb_head);

  reply	other threads:[~2011-02-04 12:05 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-01 17:54 2.6.38-rc3: FUSE (sshfs) hangs under load Dmitry Torokhov
2011-02-02 11:52 ` Miklos Szeredi
2011-02-02 16:52   ` Dmitry Torokhov
2011-02-03  6:55     ` Dmitry Torokhov
2011-02-03 11:13       ` Miklos Szeredi
2011-02-03 19:41         ` Dmitry Torokhov
2011-02-04  6:49           ` Wireless regression (was 2.6.38-rc3: FUSE (sshfs) hangs under load) Dmitry Torokhov
2011-02-04 11:41             ` Felix Fietkau
2011-02-04 12:05               ` Felix Fietkau [this message]
2011-02-07  8:06                 ` Dmitry Torokhov

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=4D4BEB99.4060202@openwrt.org \
    --to=nbd@openwrt.org \
    --cc=dmitry.torokhov@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-wireless@vger.kernel.org \
    --cc=linville@tuxdriver.com \
    --cc=miklos@szeredi.hu \
    --subject='Re: Wireless regression (was 2.6.38-rc3: FUSE (sshfs) hangs under load)' \
    /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

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).