From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 47938183CB8; Fri, 29 Nov 2024 09:54:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732874086; cv=none; b=j85hn5cC0Jktg51zT7HULbe1tAx0dtOfO3H/TBhG4ZawJ3E5T1sa2zMXmIfNdNLM2/BOz9nH9AJGqdLHKACvrjW0qgwkBpWyvyXYyatiks8vvunQd6wH7LoID2KQy+qkb5pOHHTR4o+5I1leBkNRjpkj++HUIgS20YKO4aXVvlY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732874086; c=relaxed/simple; bh=KL4bVis3gEo0B4TOmVGIBjdTbMicbca8z4NKFTxx3A4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=DNdARoe6R9AFTQmqXBH3tuECVT+Z1hyRT4WexJvrxsyex52NWgyyS1GeDzVylRnywD8jbTDBH+V9LnI2NP4Ea0ATqtIv6zWQZwIoC2AAzVPoUqSFW3esz4ycWP2e/yakNwdAnl0MXhsxvXGeKL8pjghof/3DP6xgMeyXmQjAm/c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=KHsdzp7a; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="KHsdzp7a" Received: from [192.168.88.20] (91-157-155-49.elisa-laajakaista.fi [91.157.155.49]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 91EC0A8F; Fri, 29 Nov 2024 10:54:14 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1732874055; bh=KL4bVis3gEo0B4TOmVGIBjdTbMicbca8z4NKFTxx3A4=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=KHsdzp7a4AV03+w/uEFFdkB8i8wbNRS9goa6OVXNI3EQJkuYdVOPnpRRVWCR9b/Zm sK9ah/osEiC+EcVpYqOQXJC6rWKfR/Kc/e9VFPzXd0H/DNMfsfSUg3yjct91oz76+5 WunRYG7+W3dPdiUFun0fky7U/aaYlqln8HvCzUKY= Message-ID: <141bbac1-5289-4335-a566-387721439bef@ideasonboard.com> Date: Fri, 29 Nov 2024 11:54:35 +0200 Precedence: bulk X-Mailing-List: linux-i2c@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 8/9] i2c: Support dynamic address translation To: Romain Gantois Cc: Thomas Petazzoni , Kory Maincent , linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-media@vger.kernel.org, linux-gpio@vger.kernel.org, Wolfram Sang , Luca Ceresoli , Andi Shyti , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Derek Kiernan , Dragan Cvetic , Arnd Bergmann , Greg Kroah-Hartman , Mauro Carvalho Chehab , Linus Walleij , Bartosz Golaszewski , Cosmin Tanislav References: <20241125-fpc202-v3-0-34e86bcb5b56@bootlin.com> <20241125-fpc202-v3-8-34e86bcb5b56@bootlin.com> Content-Language: en-US From: Tomi Valkeinen Autocrypt: addr=tomi.valkeinen@ideasonboard.com; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi Romain, On 25/11/2024 10:45, Romain Gantois wrote: > The i2c-atr module keeps a list of associations between I2C client aliases > and I2C addresses. This represents the address translation table which is > programmed into an ATR channel at any given time. This list is only updated > when a new client is bound to the channel. > > However in some cases, an ATR channel can have more downstream clients than > available aliases. One example of this is an SFP module that is bound to an > FPC202 port. The FPC202 port can only access up to two logical I2C > addresses. However, the SFP module may expose up to three logical I2C > addresses: its EEPROM on 7-bit addresses 0x50 and 0x51, and a PHY > transceiver on address 0x56. > > In cases like these, it is necessary to reconfigure the channel's > translation table on the fly, so that all three I2C addresses can be > accessed when needed. > > Add an optional "dynamic_c2a" flag to the i2c-atr module which allows it to > provide on-the-fly address translation. This is achieved by modifying an > ATR channel's translation table whenever an I2C transaction with unmapped > clients is requested. > > Add a mutex to protect alias_list. This prevents > i2c_atr_dynamic_attach/detach_addr from racing with the bus notifier > handler to modify alias_list. > > Signed-off-by: Romain Gantois > --- > drivers/i2c/i2c-atr.c | 244 ++++++++++++++++++++++++++++++++---------- > drivers/media/i2c/ds90ub960.c | 2 +- > include/linux/i2c-atr.h | 13 ++- > 3 files changed, 202 insertions(+), 57 deletions(-) This fails with: WARNING: CPU: 1 PID: 360 at lib/list_debug.c:35 __list_add_valid_or_report+0xe4/0x100 as the i2c_atr_create_c2a() calls list_add(), but i2c_atr_attach_addr(), which is changed to use i2c_atr_create_c2a(), also calls list_add(). Also, if you add i2c_atr_create_c2a() which hides the allocation and list_add, I think it makes sense to add a i2c_atr_destroy_c2a() to revert that. There's also a memory error "BUG: KASAN: slab-use-after-free in __lock_acquire+0xc4/0x375c" (see below) when unloading the ub960 or ub953 driver. I haven't looked at that yet. Tomi 316.204193] BUG: KASAN: slab-use-after-free in __lock_acquire+0xc4/0x375c [ 316.211059] Read of size 4 at addr cc44d558 by task rmmod/1505 [ 316.216979] [ 316.218475] CPU: 1 UID: 0 PID: 1505 Comm: rmmod Not tainted 6.12.0+ #2 [ 316.225097] Hardware name: Generic DRA74X (Flattened Device Tree) [ 316.231231] Call trace: [ 316.231262] unwind_backtrace from show_stack+0x18/0x1c [ 316.239105] show_stack from dump_stack_lvl+0x6c/0x8c [ 316.244232] dump_stack_lvl from print_report+0x130/0x538 [ 316.249694] print_report from kasan_report+0x98/0xd8 [ 316.254821] kasan_report from __lock_acquire+0xc4/0x375c [ 316.260284] __lock_acquire from lock_acquire.part.0+0x128/0x340 [ 316.266357] lock_acquire.part.0 from _raw_spin_lock+0x4c/0x5c [ 316.272247] _raw_spin_lock from i2c_atr_release_alias+0x20/0x98 [i2c_atr] [ 316.279235] i2c_atr_release_alias [i2c_atr] from i2c_atr_bus_notifier_call+0x150/0x46c [i2c_atr] [ 316.288238] i2c_atr_bus_notifier_call [i2c_atr] from notifier_call_chain+0x68/0x23c [ 316.296081] notifier_call_chain from blocking_notifier_call_chain+0x5c/0x74 [ 316.303192] blocking_notifier_call_chain from bus_notify+0x3c/0x48 [ 316.309539] bus_notify from device_del+0xf0/0x514 [ 316.314392] device_del from device_unregister+0x28/0x80 [ 316.319763] device_unregister from __unregister_client+0x84/0x90 [ 316.325927] __unregister_client from device_for_each_child+0xc0/0x12c [ 316.332550] device_for_each_child from i2c_del_adapter+0x28c/0x45c [ 316.338897] i2c_del_adapter from i2c_atr_del_adapter+0x10c/0x250 [i2c_atr] [ 316.345947] i2c_atr_del_adapter [i2c_atr] from ub953_remove+0x48/0xcc [ds90ub953] [ 316.353637] ub953_remove [ds90ub953] from i2c_device_remove+0x54/0xf8 [ 316.360260] i2c_device_remove from device_release_driver_internal+0x218/0x2a8 [ 316.367553] device_release_driver_internal from bus_remove_device+0x130/0x1cc [ 316.374847] bus_remove_device from device_del+0x1f8/0x514 [ 316.380401] device_del from device_unregister+0x28/0x80 [ 316.385772] device_unregister from ub960_remove+0xb0/0x244 [ds90ub960] [ 316.392517] ub960_remove [ds90ub960] from i2c_device_remove+0x54/0xf8 [ 316.399139] i2c_device_remove from device_release_driver_internal+0x218/0x2a8 [ 316.406433] device_release_driver_internal from driver_detach+0x6c/0xc4 [ 316.413238] driver_detach from bus_remove_driver+0xa0/0x134 [ 316.418945] bus_remove_driver from i2c_del_driver+0x48/0x84 [ 316.424682] i2c_del_driver from sys_delete_module+0x280/0x3cc [ 316.430572] sys_delete_module from ret_fast_syscall+0x0/0x1c