From: Leon Romanovsky <leon@kernel.org>
To: Cong Wang <xiyou.wangcong@gmail.com>
Cc: David Miller <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Arjan van de Ven <arjan@linux.intel.com>,
Jamal Hadi Salim <jhs@mojatatu.com>,
Jiri Pirko <jiri@resnulli.us>,
Linux Kernel Network Developers <netdev@vger.kernel.org>,
itayav@mellanox.com
Subject: Re: [PATCH net] net/sched: Don't print dump stack in event of transmission timeout
Date: Fri, 3 Apr 2020 07:36:11 +0300 [thread overview]
Message-ID: <20200403043611.GC80989@unreal> (raw)
In-Reply-To: <CAM_iQpWvkTTRwV5-tj1Hj_a8hG2X-udU0BG2VXDbukuKFeN=JA@mail.gmail.com>
On Thu, Apr 02, 2020 at 09:30:15PM -0700, Cong Wang wrote:
> On Thu, Apr 2, 2020 at 6:02 PM David Miller <davem@davemloft.net> wrote:
> >
> > From: Leon Romanovsky <leon@kernel.org>
> > Date: Thu, 2 Apr 2020 18:23:36 +0300
> >
> > > In event of transmission timeout, the drivers are given an opportunity
> > > to recover and continue to work after some in-house cleanups.
> > >
> > > Such event can be caused by HW bugs, wrong congestion configurations
> > > and many more other scenarios. In such case, users are interested to
> > > get a simple "NETDEV WATCHDOG ... " print, which points to the relevant
> > > netdevice in trouble.
> > >
> > > The dump stack printed later was added in the commit b4192bbd85d2
> > > ("net: Add a WARN_ON_ONCE() to the transmit timeout function") to give
> > > extra information, like list of the modules and which driver is involved.
> > >
> > > While the latter is already printed in "NETDEV WATCHDOG ... ", the list
> > > of modules rarely needed and can be collected later.
> > >
> > > So let's remove the WARN_ONCE() and make dmesg look more user-friendly in
> > > large cluster setups.
> >
> > Software bugs play into these situations and on at least two or three
> > occasions I know that the backtrace hinted at the cause of the bug.
> >
>
> I don't see how a timer stack trace could help to debug this issue
> in any scenario, the messages out of this stack trace are indeed
> helpful.
>
> On the other hand, a stack trace does help to get some attention
> via ABRT, but at least for us we now use rasdaemon to capture
> this, so I am 100% fine to remove this stack trace.
Thanks
>
> Thanks.
next prev parent reply other threads:[~2020-04-03 4:36 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-02 15:23 [PATCH net] net/sched: Don't print dump stack in event of transmission timeout Leon Romanovsky
2020-04-02 22:57 ` Jakub Kicinski
2020-04-03 4:33 ` Cong Wang
2020-04-03 4:48 ` Leon Romanovsky
2020-04-03 1:02 ` David Miller
2020-04-03 4:30 ` Cong Wang
2020-04-03 4:36 ` Leon Romanovsky [this message]
2020-04-03 4:40 ` Leon Romanovsky
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