From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Fri, 11 Nov 2011 01:48:50 +0100 (CET) Received: from mail3.caviumnetworks.com ([12.108.191.235]:18070 "EHLO mail3.caviumnetworks.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S1904249Ab1KKAsp (ORCPT ); Fri, 11 Nov 2011 01:48:45 +0100 Received: from caexch01.caveonetworks.com (Not Verified[192.168.16.9]) by mail3.caviumnetworks.com with MailMarshal (v6,7,2,8378) id ; Thu, 10 Nov 2011 16:50:07 -0800 Received: from caexch01.caveonetworks.com ([192.168.16.9]) by caexch01.caveonetworks.com with Microsoft SMTPSVC(6.0.3790.4675); Thu, 10 Nov 2011 16:48:43 -0800 Received: from dd1.caveonetworks.com ([64.2.3.195]) by caexch01.caveonetworks.com over TLS secured channel with Microsoft SMTPSVC(6.0.3790.4675); Thu, 10 Nov 2011 16:48:43 -0800 Message-ID: <4EBC70EB.7080002@cavium.com> Date: Thu, 10 Nov 2011 16:48:43 -0800 From: David Daney User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.15) Gecko/20101027 Fedora/3.0.10-1.fc12 Thunderbird/3.0.10 MIME-Version: 1.0 To: Tabi Timur-B04825 CC: "netdev@vger.kernel.org" , "davem@davemloft.net" , "linux-mips@linux-mips.org" Subject: Re: [PATCH] netdev/phy: Use mdiobus_read() so that proper locks are taken. References: <1317419482-25655-1-git-send-email-david.daney@cavium.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 11 Nov 2011 00:48:43.0585 (UTC) FILETIME=[A981EB10:01CCA00B] X-archive-position: 31520 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: david.daney@cavium.com Precedence: bulk X-list: linux-mips Return-Path: X-Keywords: X-UID: 9880 On 11/10/2011 04:29 PM, Tabi Timur-B04825 wrote: > On Fri, Sep 30, 2011 at 4:51 PM, David Daney wrote: >> Accesses to the mdio busses must be done with the mdio_lock to ensure >> proper operation. Conveniently we have the helper function >> mdiobus_read() to do that for us. Lets use it in get_phy_id() instead >> of accessing the bus without the lock held. >> >> Signed-off-by: David Daney >> --- > > This patch is causing me problems, but I'm not exactly certain how. I think it is because fsl_pq_mdio_probe() is defective. You are using the bus, by calling fsl_pq_mdio_find_free(), before the driver is registered and initialized by calling of_mdiobus_register(). At least that is my take on it. David Daney > The problems only appear when I add some unrelated code to my platform > file (p1022ds.c), but the trap is definitely in the phy code: > > Fixed MDIO Bus: probed > INFO: trying to register non-static key. > the code is fine but needs lockdep annotation. > turning off the locking correctness validator. > Call Trace: > [e685dcc0] [c0008c7c] show_stack+0x44/0x154 (unreliable) > [e685dd00] [c007bf74] __lock_acquire+0x1374/0x1824 > [e685ddb0] [c007c870] lock_acquire+0x4c/0x68 > [e685ddd0] [c0455fe4] mutex_lock_nested+0x6c/0x394 > [e685de30] [c02acc08] mdiobus_read+0x3c/0x78 > [e685de50] [c02abc98] get_phy_id+0x24/0x80 > [e685de70] [c02b1860] fsl_pq_mdio_probe+0x3ac/0x458 > [e685deb0] [c027ba2c] platform_drv_probe+0x20/0x30 > [e685dec0] [c027a4b0] driver_probe_device+0xa4/0x1d4 > [e685dee0] [c027a6a4] __driver_attach+0xc4/0xc8 > [e685df00] [c027939c] bus_for_each_dev+0x60/0x9c > [e685df30] [c027a0e4] driver_attach+0x24/0x34 > [e685df40] [c0279d30] bus_add_driver+0x1b0/0x278 > [e685df70] [c027aab8] driver_register+0x88/0x154 > [e685df90] [c027bd5c] platform_driver_register+0x68/0x78 > [e685dfa0] [c05d47c8] fsl_pq_mdio_init+0x18/0x28 > [e685dfb0] [c0001eb8] do_one_initcall+0x34/0x1ac > [e685dfe0] [c05b984c] kernel_init+0xa0/0x13c > [e685dff0] [c000e588] kernel_thread+0x4c/0x68 > Unable to handle kernel paging request for data at address 0x00000000 > Faulting instruction address: 0xc0456080 > Oops: Kernel access of bad area, sig: 11 [#1] > SMP NR_CPUS=8 P1022 DS > Modules linked in: > NIP: c0456080 LR: c0456068 CTR: 00000000 > REGS: e685dd20 TRAP: 0300 Not tainted (3.2.0-10b-00092-g66f2305-dirty) > MSR: 00021000 CR: 22042044 XER: 20000000 > DEAR: 00000000, ESR: 00800000 > TASK = e6860000[1] 'swapper' THREAD: e685c000 CPU: 0 > GPR00: ffffffff e685ddd0 e6860000 e6e58028 e685ddd8 e685c000 e685dde4 00000002 > GPR08: 00000000 00000000 00000000 00000000 44042022 40401800 00000000 00000000 > GPR16: c0000a00 00000014 3fffffff 03ff9000 00000015 7ff3a68c c061e000 00000000 > GPR24: e6e5804c e685ddd8 e6e5802c 00029000 e6860000 c0620000 e685c000 e6e58028 > NIP [c0456080] mutex_lock_nested+0x108/0x394 > LR [c0456068] mutex_lock_nested+0xf0/0x394 > Call Trace: > [e685ddd0] [c0456068] mutex_lock_nested+0xf0/0x394 (unreliable) > [e685de30] [c02acc08] mdiobus_read+0x3c/0x78 > [e685de50] [c02abc98] get_phy_id+0x24/0x80 > [e685de70] [c02b1860] fsl_pq_mdio_probe+0x3ac/0x458 > [e685deb0] [c027ba2c] platform_drv_probe+0x20/0x30 > [e685dec0] [c027a4b0] driver_probe_device+0xa4/0x1d4 > [e685dee0] [c027a6a4] __driver_attach+0xc4/0xc8 > [e685df00] [c027939c] bus_for_each_dev+0x60/0x9c > [e685df30] [c027a0e4] driver_attach+0x24/0x34 > [e685df40] [c0279d30] bus_add_driver+0x1b0/0x278 > [e685df70] [c027aab8] driver_register+0x88/0x154 > [e685df90] [c027bd5c] platform_driver_register+0x68/0x78 > [e685dfa0] [c05d47c8] fsl_pq_mdio_init+0x18/0x28 > [e685dfb0] [c0001eb8] do_one_initcall+0x34/0x1ac > [e685dfe0] [c05b984c] kernel_init+0xa0/0x13c > [e685dff0] [c000e588] kernel_thread+0x4c/0x68 > Instruction dump: > 7f24cb78 4bc21141 80bc0004 7fe3fb78 7f24cb78 4bc21325 813f0028 3b1f0024 > 933f0028 3800ffff 93010008 9121000c > 93810010 7c0004ac 7d20f828 > ---[ end trace 7cc8bbd19b132dac ]--- > note: swapper[1] exited with preempt_count 1 > Kernel panic - not syncing: Attempted to kill init! > Call Trace: > [e685dc00] [c0008c7c] show_stack+0x44/0x154 (unreliable) > [e685dc40] [c04583a0] panic+0xb4/0x1f0 > [e685dc90] [c004724c] do_exit+0x5dc/0x684 > [e685dce0] [c000b368] die+0xdc/0x1b4 > [e685dd00] [c00137fc] bad_page_fault+0xb4/0xfc > [e685dd10] [c000f998] handle_page_fault+0x7c/0x80 > --- Exception: 300 at mutex_lock_nested+0x108/0x394 > LR = mutex_lock_nested+0xf0/0x394 > [e685de30] [c02acc08] mdiobus_read+0x3c/0x78 > [e685de50] [c02abc98] get_phy_id+0x24/0x80 > [e685de70] [c02b1860] fsl_pq_mdio_probe+0x3ac/0x458 > [e685deb0] [c027ba2c] platform_drv_probe+0x20/0x30 > [e685dec0] [c027a4b0] driver_probe_device+0xa4/0x1d4 > [e685dee0] [c027a6a4] __driver_attach+0xc4/0xc8 > [e685df00] [c027939c] bus_for_each_dev+0x60/0x9c > [e685df30] [c027a0e4] driver_attach+0x24/0x34 > [e685df40] [c0279d30] bus_add_driver+0x1b0/0x278 > [e685df70] [c027aab8] driver_register+0x88/0x154 > [e685df90] [c027bd5c] platform_driver_register+0x68/0x78 > [e685dfa0] [c05d47c8] fsl_pq_mdio_init+0x18/0x28 > [e685dfb0] [c0001eb8] do_one_initcall+0x34/0x1ac > [e685dfe0] [c05b984c] kernel_init+0xa0/0x13c > [e685dff0] [c000e588] kernel_thread+0x4c/0x68 > Rebooting in 1 seconds.. > > I'm still trying to narrow down what's causing the problem, but when I > revert this patch, I don't see these traps. > > Sometimes, I don't get the trap, but I get a hang on this line: > > int mdiobus_read(struct mii_bus *bus, int addr, u32 regnum) > { > int retval; > > BUG_ON(in_interrupt()); > > ---> mutex_lock(&bus->mdio_lock); >