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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B865EC433FE for ; Mon, 7 Mar 2022 14:36:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243281AbiCGOgz (ORCPT ); Mon, 7 Mar 2022 09:36:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39264 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233330AbiCGOgy (ORCPT ); Mon, 7 Mar 2022 09:36:54 -0500 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B8D3B7D01F; Mon, 7 Mar 2022 06:35:59 -0800 (PST) Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 8EDBF478; Mon, 7 Mar 2022 15:35:57 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1646663757; bh=SCTLfi1Xfty9Lg4VEGF2AZggP+lYSWFOBLF0oWztcQw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=f57QYuY7iVWUBd6yz9Re15QtkkcV/ETdcVJIxqXbsQoQltXaVvmutjDZdvJsj4Qvq MNsJrWL/rGiJxoJ9+L9GGDM2ODm/5baUgCCS7Gu+hC1GwrOflHn6tIe0zgsgQZZo+o seJpVqWcykhmdPP4a3gh3DVgoOGRn2pG338ohpTM= Date: Mon, 7 Mar 2022 16:35:44 +0200 From: Laurent Pinchart To: Kieran Bingham Cc: Jacopo Mondi , Laurentiu Palcu , Mauro Carvalho Chehab , Niklas =?utf-8?Q?S=C3=B6derlund?= , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] media: i2c: max9286: fix kernel oops when removing module Message-ID: References: <20220307133750.29708-1-laurentiu.palcu@oss.nxp.com> <164666323196.11309.2192554853786525085@Monstersaurus> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <164666323196.11309.2192554853786525085@Monstersaurus> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 07, 2022 at 02:27:11PM +0000, Kieran Bingham wrote: > Hi Laurentiu, > > Quoting Laurentiu Palcu (2022-03-07 13:37:50) > > When removing the max9286 module we get a kernel oops: > > > > Unable to handle kernel paging request at virtual address 000000aa00000094 > > Mem abort info: > > ESR = 0x96000004 > > EC = 0x25: DABT (current EL), IL = 32 bits > > SET = 0, FnV = 0 > > EA = 0, S1PTW = 0 > > FSC = 0x04: level 0 translation fault > > Data abort info: > > ISV = 0, ISS = 0x00000004 > > CM = 0, WnR = 0 > > user pgtable: 4k pages, 48-bit VAs, pgdp=0000000880d85000 > > [000000aa00000094] pgd=0000000000000000, p4d=0000000000000000 > > Internal error: Oops: 96000004 [#1] PREEMPT SMP > > Modules linked in: fsl_jr_uio caam_jr rng_core libdes caamkeyblob_desc caamhash_desc caamalg_desc crypto_engine max9271 authenc crct10dif_ce mxc_jpeg_encdec > > CPU: 2 PID: 713 Comm: rmmod Tainted: G C 5.15.5-00057-gaebcd29c8ed7-dirty #5 > > Hardware name: Freescale i.MX8QXP MEK (DT) > > pstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) > > pc : i2c_mux_del_adapters+0x24/0xf0 > > lr : max9286_remove+0x28/0xd0 [max9286] > > sp : ffff800013a9bbf0 > > x29: ffff800013a9bbf0 x28: ffff00080b6da940 x27: 0000000000000000 > > x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000 > > x23: ffff000801a5b970 x22: ffff0008048b0890 x21: ffff800009297000 > > x20: ffff0008048b0f70 x19: 000000aa00000064 x18: 0000000000000000 > > x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 > > x14: 0000000000000014 x13: 0000000000000000 x12: ffff000802da49e8 > > x11: ffff000802051918 x10: ffff000802da4920 x9 : ffff000800030098 > > x8 : 0101010101010101 x7 : 7f7f7f7f7f7f7f7f x6 : fefefeff6364626d > > x5 : 8080808000000000 x4 : 0000000000000000 x3 : 0000000000000000 > > x2 : ffffffffffffffff x1 : ffff00080b6da940 x0 : 0000000000000000 > > Call trace: > > i2c_mux_del_adapters+0x24/0xf0 > > max9286_remove+0x28/0xd0 [max9286] > > i2c_device_remove+0x40/0x110 > > __device_release_driver+0x188/0x234 > > driver_detach+0xc4/0x150 > > bus_remove_driver+0x60/0xe0 > > driver_unregister+0x34/0x64 > > i2c_del_driver+0x58/0xa0 > > max9286_i2c_driver_exit+0x1c/0x490 [max9286] > > __arm64_sys_delete_module+0x194/0x260 > > invoke_syscall+0x48/0x114 > > el0_svc_common.constprop.0+0xd4/0xfc > > do_el0_svc+0x2c/0x94 > > el0_svc+0x28/0x80 > > el0t_64_sync_handler+0xa8/0x130 > > el0t_64_sync+0x1a0/0x1a4 > > > > The Oops happens because the I2C client data does not point to > > max9286_priv anymore but to v4l2_subdev. The change happened in > > max9286_init() which calls v4l2_i2c_subdev_init() later on... > > > > I think this needs a Fixes tag, but it looks like it happened when we > merged the driver. So that makes it: > > Fixes: 66d8c9d2422d ("media: i2c: Add MAX9286 driver") > > I see in max9286_probe() we set > i2c_set_clientdata(client, (struct max9286_priv) priv); > > And indeed, then we call > > max9286_init() > max9286_v4l2_register() > v4l2_i2c_subdev_init(&priv->sd, priv->client, &max9286_subdev_ops); > > So I think this patch should probably also remove the call to > i2c_set_clientdata() in probe to prevent confusion. Agreed. > > Signed-off-by: Laurentiu Palcu > > --- > > drivers/media/i2c/max9286.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c > > index d2a4915ed9f7..04f5b7e3a9e5 100644 > > --- a/drivers/media/i2c/max9286.c > > +++ b/drivers/media/i2c/max9286.c > > @@ -1385,7 +1385,7 @@ static int max9286_probe(struct i2c_client *client) > > > > static int max9286_remove(struct i2c_client *client) > > { > > - struct max9286_priv *priv = i2c_get_clientdata(client); > > + struct max9286_priv *priv = sd_to_max9286(i2c_get_clientdata(client)); > > What happens if the module load failed before calling max9286_init(), in > that case, would the i2c_get_clientdata() return NULL? > > If so, should this be checked? .remove() isn't called if .probe() fails, so it should be fine > > > > i2c_mux_del_adapters(priv->mux); > > -- Regards, Laurent Pinchart