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From: Cong Wang <xiyou.wangcong@gmail.com>
To: Dave Jones <davej@codemonkey.org.uk>,
	Meelis Roos <mroos@linux.ee>, LKML <linux-kernel@vger.kernel.org>,
	Linux Kernel Network Developers <netdev@vger.kernel.org>
Subject: Re: netconsole warning in 4.19.0-rc7
Date: Tue, 16 Oct 2018 22:16:57 -0700	[thread overview]
Message-ID: <CAM_iQpWJfMWRY1TZRDz+GgjGJj_ySjmb42hjPyAtcakzWqnLeg@mail.gmail.com> (raw)
In-Reply-To: <20181017035038.czaqown24rnjn2pw@codemonkey.org.uk>

On Tue, Oct 16, 2018 at 8:50 PM Dave Jones <davej@codemonkey.org.uk> wrote:
>
> On Tue, Oct 16, 2018 at 11:40:47PM -0400, Dave Jones wrote:
>
>  >  > This is exactly what I mentioned in my review here:
>  >  > https://marc.info/?l=linux-netdev&m=153816136624679&w=2
>  >  >
>  >  > "But irq is disabled here, so not sure if rcu_read_lock_bh()
>  >  > could cause trouble... "
>  >
>  > Not sure why this didn't show up for me when I was developing that
>  > patch, but I can now reproduce this.  The patch below fixes it for
>  > me, but I'm not sure if there are still any side-effects.
>  > There's also a missed unlock in the error path.
>
> I took another look at that error path. Turns out this is all we need I
> think..

Double check if rcu_dereference_bh() is happy with it.

Don't trust me, enable the relevant Kconfig and trust your test. ;)

  reply	other threads:[~2018-10-17 13:11 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-10 12:06 netconsole warning in 4.19.0-rc7 Meelis Roos
2018-10-11  5:34 ` Cong Wang
2018-10-12 14:32   ` Dave Jones
2018-10-17  3:40   ` Dave Jones
2018-10-17  3:50     ` Dave Jones
2018-10-17  5:16       ` Cong Wang [this message]
2018-10-17  6:22       ` Meelis Roos
2018-10-18 14:59         ` Dave Jones
2018-10-19  9:51           ` Meelis Roos
2018-10-19 13:47             ` Dave Jones
2018-10-19 17:45               ` David Miller

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