Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20200615190119.382589-1-drc@linux.vnet.ibm.com>
In-Reply-To: <20200615190119.382589-1-drc@linux.vnet.ibm.com>
From:   Michael Chan <michael.chan@broadcom.com>
Date:   Mon, 15 Jun 2020 13:45:36 -0700
Message-ID: <CACKFLimd0a=Y8WyvqCt4BD7SU_Cg1vQ=baKs6-uPv0dZuCm=mw@mail.gmail.com>
Subject: Re: [PATCH] tg3: driver sleeps indefinitely when EEH errors exceed eeh_max_freezes
To:     David Christensen <drc@linux.vnet.ibm.com>
Cc:     Netdev <netdev@vger.kernel.org>,
        Siva Reddy Kallam <siva.kallam@broadcom.com>,
        Prashant Sreedharan <prashant@broadcom.com>,
        Michael Chan <mchan@broadcom.com>,
        open list <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, Jun 15, 2020 at 12:01 PM David Christensen
<drc@linux.vnet.ibm.com> wrote:
>
> The driver function tg3_io_error_detected() calls napi_disable twice,
> without an intervening napi_enable, when the number of EEH errors exceeds
> eeh_max_freezes, resulting in an indefinite sleep while holding rtnl_lock.
>
> The function is called once with the PCI state pci_channel_io_frozen and
> then called again with the state pci_channel_io_perm_failure when the
> number of EEH failures in an hour exceeds eeh_max_freezes.
>
> Protecting the calls to napi_enable/napi_disable with a new state
> variable prevents the long sleep.

This works, but I think a simpler fix is to check tp->pcierr_recovery
in tg3_io_error_detected() and skip most of the tg3 calls (including
the one that disables NAPI) if the flag is true.