From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 28530C432BE for ; Wed, 4 Aug 2021 21:48:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0B3306105A for ; Wed, 4 Aug 2021 21:48:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234336AbhHDVsP (ORCPT ); Wed, 4 Aug 2021 17:48:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42570 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234313AbhHDVsO (ORCPT ); Wed, 4 Aug 2021 17:48:14 -0400 Received: from mail-yb1-xb31.google.com (mail-yb1-xb31.google.com [IPv6:2607:f8b0:4864:20::b31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 80C16C061798 for ; Wed, 4 Aug 2021 14:48:01 -0700 (PDT) Received: by mail-yb1-xb31.google.com with SMTP id z128so5891473ybc.10 for ; Wed, 04 Aug 2021 14:48:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=KRoLUTCoSR0bH9PoFJhlJID9z3ogqrNBELOHgMdcgZI=; b=Tm8u/fBt2jfvpCHpu9LdTriauh41G7MbJ/k7/1kIxQJdpa0yL5ppkHMPaney174HJd F6BZJC1Vsr/w7a7elTuygtEl5Za6qZXAeUwWCleO++VdpvXuAyb7fABAnQ50RViJA+Rk dcae/D+aSZvnrw/jEB/+s+7RcLa0fEu8ezV0O+bFyQCJkEDQX/RzBXux6m6GBamCdgHw cQRCd2tdHpEiCCIsOvV7DoZpQvCzcwI9UiQkNOuioJR+ekL4lwsLvmJUUNieqvjYv9Iv EifQp/eG9NxFAeUFAlt+Jp4ORTFA89cWUoh4p2ndaj1SuptzLudhkG77S/1fT4e3tM2q XDIw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=KRoLUTCoSR0bH9PoFJhlJID9z3ogqrNBELOHgMdcgZI=; b=ETnEILjAhDUa6ZPNyoHm/ICQfJj6687SKc8tFLDMlcxhG5BYIev7+Wi+H9ky9B130K OljK1wagj4e3BuLTV9D28AEIAFvW6spejUfh4NH22n/Zf+6fNjbnHCYMIVr32q9S1eAz r39GgtTJWMxT7diR/jejrj71eKvQnSnSvE6whU/ot/HEAzYINKPHt4cucsMGZYRCxarN iacQEByoNu9lya0h2Dhwjl0WUMXgDfTJnwNv6vJRA95oq6M7F4JAgygkvu+QGw3evIp+ vp6H8YZeRGVtxvGu7nI0Fk7pR/1sOWMNm+dcstDt4u9LDwknzEjFS2fBMrihpnv9DJx7 Bmzw== X-Gm-Message-State: AOAM533yM0waTYS7Qj2EHSuZQg2fpCzU5VpO/8jysS/HLygAko4DME3w /buIPH8wyeM0TAgyPN3+8o1aft5ilvqcj4jtcFpfRQ== X-Google-Smtp-Source: ABdhPJyISe+k/AN2pZLmSpbnlxpKTFVJtkTu7zHA3NBj4rQd64Knpc3lIPzo5Kq7m4F3BIdTEkaeICAMhnx91j5z/EU= X-Received: by 2002:a25:81ce:: with SMTP id n14mr2063907ybm.32.1628113680544; Wed, 04 Aug 2021 14:48:00 -0700 (PDT) MIME-Version: 1.0 References: <20201020072532.949137-1-narmstrong@baylibre.com> <20201020072532.949137-2-narmstrong@baylibre.com> <7hsga8kb8z.fsf@baylibre.com> <87r1hwwier.wl-maz@kernel.org> <7h7diwgjup.fsf@baylibre.com> <87im0m277h.wl-maz@kernel.org> <87sfzpwq4f.wl-maz@kernel.org> In-Reply-To: From: Saravana Kannan Date: Wed, 4 Aug 2021 14:47:24 -0700 Message-ID: Subject: Re: [PATCH 1/2] irqchip: irq-meson-gpio: make it possible to build as a module To: Marc Zyngier , Andrew Lunn Cc: Kevin Hilman , Lee Jones , Neil Armstrong , Jerome Brunet , linux-amlogic@lists.infradead.org, linux-arm-kernel , open list , netdev , Android Kernel Team Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 4, 2021 at 11:20 AM Saravana Kannan wrot= e: > > On Wed, Aug 4, 2021 at 1:50 AM Marc Zyngier wrote: > > > > On Wed, 04 Aug 2021 02:36:45 +0100, > > Saravana Kannan wrote: > > > > Hi Saravana, > > > > Thanks for looking into this. > > You are welcome. I just don't want people to think fw_devlink is broken := ) > > > > > [...] > > > > > > Saravana, could you please have a look from a fw_devlink perspectiv= e? > > > > > > Sigh... I spent several hours looking at this and wrote up an analysi= s > > > and then realized I might be looking at the wrong DT files. > > > > > > Marc, can you point me to the board file in upstream that corresponds > > > to the platform in which you see this issue? I'm not asking for [1], > > > but the actual final .dts (not .dtsi) file that corresponds to the > > > platform/board/system. > > > > The platform I can reproduce this on is described in > > arch/arm64/boot/dts/amlogic/meson-sm1-khadas-vim3l.dts. It is an > > intricate maze of inclusion, node merge and other DT subtleties. I > > suggest you look at the decompiled version to get a view of the > > result. > > Thanks. After decompiling it, it looks something like (stripped a > bunch of reg and address properties and added the labels back): > > eth_phy: mdio-multiplexer@4c000 { > compatible =3D "amlogic,g12a-mdio-mux"; > clocks =3D <0x02 0x13 0x1e 0x02 0xb1>; > clock-names =3D "pclk\0clkin0\0clkin1"; > mdio-parent-bus =3D <0x22>; > > ext_mdio: mdio@0 { > reg =3D <0x00>; > > ethernet-phy@0 { > max-speed =3D <0x3e8>; > interrupt-parent =3D <0x23>; > interrupts =3D <0x1a 0x08>; > phandle =3D <0x16>; > }; > }; > > int_mdio: mdio@1 { > ... > } > } > > And phandle 0x23 refers to the gpio_intc interrupt controller with the > modular driver. > > > > Based on your error messages, it's failing for mdio@0 which > > > corresponds to ext_mdio. But none of the board dts files in upstream > > > have a compatible property for "ext_mdio". Which means fw_devlink > > > _should_ propagate the gpio_intc IRQ dependency all the way up to > > > eth_phy. > > > > > > Also, in the failing case, can you run: > > > ls -ld supplier:* > > > > > > in the /sys/devices/..../ folder that corresponds to the > > > "eth_phy: mdio-multiplexer@4c000" DT node and tell me what it shows? > > > > Here you go: > > > > root@tiger-roach:~# find /sys/devices/ -name 'supplier*'|grep -i mdio |= xargs ls -ld > > lrwxrwxrwx 1 root root 0 Aug 4 09:47 /sys/devices/platform/soc/ff60000= 0.bus/ff64c000.mdio-multiplexer/supplier:platform:ff63c000.system-controlle= r:clock-controller -> ../../../../virtual/devlink/platform:ff63c000.system-= controller:clock-controller--platform:ff64c000.mdio-multiplexer > > As we discussed over chat, this was taken after the mdio-multiplexer > driver "successfully" probes this device. This will cause > SYNC_STATE_ONLY device links created by fw_devlink to be deleted > (because they are useless after a device probes). So, this doesn't > show the info I was hoping to demonstrate. > > In any case, one can see that fw_devlink properly created the device > link for the clocks dependency. So fw_devlink is parsing this node > properly. But it doesn't create a similar probe order enforcing device > link between the mdio-multiplexer and the gpio_intc because the > dependency is only present in a grand child DT node (ethernet-phy@0 > under ext_mdio). So fw_devlink is working as intended. > > I spent several hours squinting at the code/DT yesterday. Here's what > is going on and causing the problem: > > The failing driver in this case is > drivers/net/mdio/mdio-mux-meson-g12a.c. And the only DT node it's > handling is what I pasted above in this email. In the failure case, > the call flow is something like this: > > g12a_mdio_mux_probe() > -> mdio_mux_init() > -> of_mdiobus_register(ext_mdio DT node) > -> of_mdiobus_register_phy(ext_mdio DT node) > -> several calls deep fwnode_mdiobus_phy_device_register(ethernet_phy DT = node) > -> Tried to get the IRQ listed in ethernet_phy and fails with > -EPROBE_DEFER because the IRQ driver isn't loaded yet. > > The error is propagated correctly all the way up to of_mdiobus_register()= , but > mdio_mux_init() ignores the -EPROBE_DEFER from of_mdiobus_register() and = just > continues on with the rest of the stuff and returns success as long as > one of the child nodes (in this case int_mdio) succeeds. > > Since the probe returns 0 without really succeeding, networking stuff > just fails badly after this. So, IMO, the real problem is with > mdio_mux_init() not propagating up the -EPROBE_DEFER. I gave Marc a > quick hack (pasted at the end of this email) to test my theory and he > confirmed that it fixes the issue (a few deferred probes later, things > work properly). > > Andrew, I don't see any good reason for mdio_mux_init() not > propagating the errors up correctly (at least for EPROBE_DEFER). I'll > send a patch to fix this. Please let me know if there's a reason it > has to stay as-is. I sent out the proper fix as a series: https://lore.kernel.org/lkml/20210804214333.927985-1-saravanak@google.com/T= /#t Marc, can you give it a shot please? -Saravana > > -Saravana > > index 110e4ee85785..d973a267151f 100644 > --- a/drivers/net/mdio/mdio-mux.c > +++ b/drivers/net/mdio/mdio-mux.c > @@ -170,6 +170,9 @@ int mdio_mux_init(struct device *dev, > child_bus_node); > mdiobus_free(cb->mii_bus); > devm_kfree(dev, cb); > + /* Not a final fix. I think it can cause UAF issu= es. */ > + mdio_mux_uninit(pb); > + return r; > } else { > cb->next =3D pb->children; > pb->children =3D cb;