Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <13b0813576f57add0d2eacb519eedec73fcf1920.camel@mediatek.com>
Subject: Re: [PATCH] PCI: mvebu: Dispose INTx irqs prior to removing INTx
 domain
From:   Jianjun Wang <jianjun.wang@mediatek.com>
To:     Pali =?ISO-8859-1?Q?Roh=E1r?= <pali@kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
        Lorenzo Pieralisi <lpieralisi@kernel.org>,
        Rob Herring <robh@kernel.org>,
        Krzysztof =?UTF-8?Q?Wilczy=C5=84ski?= <kw@linux.com>,
        Hajo Noerenberg <hajo-linux-bugzilla@noerenberg.de>
CC:     <linux-pci@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>
Date:   Tue, 9 Aug 2022 09:26:59 +0800
In-Reply-To: <20220710001421.lqwprzgn5jrblqcu@pali>
References: <20220709161858.15031-1-pali@kernel.org>
         <20220710001421.lqwprzgn5jrblqcu@pali>
Content-Type: text/plain; charset="UTF-8"
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Hi Pali,

On Sun, 2022-07-10 at 02:14 +0200, Pali Rohár wrote:
> On Saturday 09 July 2022 18:18:58 Pali Rohár wrote:
> > Documentation for irq_domain_remove() says that all mapping within
> > the
> > domain must be disposed prior to domain remove.
> > 
> > Currently INTx irqs are not disposed in pci-mvebu.c device unbind
> > callback
> > which cause that kernel crashes after unloading driver and trying
> > to read
> > /sys/kernel/debug/irq/irqs/<num> or /proc/interrupts.
> > 
> > Fixes: ec075262648f ("PCI: mvebu: Implement support for legacy INTx
> > interrupts")
> > Reported-by: Hajo Noerenberg <hajo-linux-bugzilla@noerenberg.de>
> > Signed-off-by: Pali Rohár <pali@kernel.org>
> 
> Just to note, Hajo Noerenberg observed this issue during testing and
> debugging other unrelated issue in bugzilla [1] and triggered this
> crash
> just by calling: rmmod pci_mvebu && modprobe pci-mvebu && cat
> /proc/interrupts
> 
> I suppose that other pci controller drivers with unbind / rmmod
> support
> would suffer from same issues.

FYI, we found the same issue after unloading the PCIe controller
driver, if this is the proper way to dispose the INTx irqs, I'll send a
similar patch for MediaTek's PCIe controller driver.

Thanks.