From: David Miller <davem@davemloft.net>
To: f.fainelli@gmail.com
Cc: netdev@vger.kernel.org, edumazet@google.com, jqiaoulk@gmail.com
Subject: Re: [PATCH net] net: systemport: Fix 64-bit stats deadlock
Date: Fri, 15 Sep 2017 14:25:11 -0700 (PDT) [thread overview]
Message-ID: <20170915.142511.221689318302073484.davem@davemloft.net> (raw)
In-Reply-To: <1505247266-42195-1-git-send-email-f.fainelli@gmail.com>
From: Florian Fainelli <f.fainelli@gmail.com>
Date: Tue, 12 Sep 2017 13:14:26 -0700
> We can enter a deadlock situation because there is no sufficient protection
> when ndo_get_stats64() runs in process context to guard against RX or TX NAPI
> contexts running in softirq, this can lead to the following lockdep splat and
> actual deadlock was experienced as well with an iperf session in the background
> and a while loop doing ifconfig + ethtool.
...
> So just remove the u64_stats_update_begin()/end() pair in ndo_get_stats64()
> since it does not appear to be useful for anything. No inconsistency was
> observed with either ifconfig or ethtool, global TX counts equal the sum of
> per-queue TX counts on a 32-bit architecture.
>
> Fixes: 10377ba7673d ("net: systemport: Support 64bit statistics")
> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Applied.
next prev parent reply other threads:[~2017-09-15 21:25 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-12 20:14 [PATCH net] net: systemport: Fix 64-bit stats deadlock Florian Fainelli
2017-09-12 21:38 ` Eric Dumazet
2017-09-12 21:48 ` Florian Fainelli
2017-09-15 21:25 ` David Miller [this message]
2017-09-15 21:28 ` Florian Fainelli
2017-09-15 21:53 ` David Miller
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