From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 A5E6848032A; Tue, 5 May 2026 14:28:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777991314; cv=none; b=faeIl1k9o56D/5J1s3x1udws6SDF8C1Q9E72jD5sYvc+5msanzjo51ukTv1Xr5svSiHcGfvBgwtZbYCcXwfIzLTraiVpd5orIvus4afugfVJHgDciCVT5jpHE1UuKmyo9IzlqjG75Kus8J3HXx1EW6EZB3oxMYT1N8MKB52mV4o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777991314; c=relaxed/simple; bh=RcSelwJi6o5XPQYFAlXWzdU/YR262F/UXpfNjyr1RgE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TDmV5TGYPkhmE/FPcX7BF46WmmQajDi5uIbpohdo9zfdAqKKdvcvNSZFJyErL//QXDUg3/uXDjPd07y5PZ88gTb2dwp2nxvNI6sWArOLm9UAJJLIT4d++WaGCLDdwsZ24qCrYdAfwK1SOMbPkYW1ZzZm3028xpO97C84AM8VFMI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=X027wd3Z; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="X027wd3Z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 65220C2BCF6; Tue, 5 May 2026 14:28:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777991314; bh=RcSelwJi6o5XPQYFAlXWzdU/YR262F/UXpfNjyr1RgE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=X027wd3Z3lGQRqvxJxidrx3NgvUesuXO4AxqXVRiOTPHXS9kTA9B7q39deT2WflXI 1+0wSCrfCN6cqYhCQ95TL+1oH31J5jjsdyKn7LR6TsqB8yspBPlZeWVz6bqv8mbY+W qs2n7TyWh1P8KbQGLj7cEn4CnJJjAO0tK1guwvqFYWACOJKE7lQFNEOhewANjU9ddR S8T6PReiIpefMOS2Yu9DXF5GbUw6cLiErWWgYoW9NJD6ttbN+gDJSZzeUuaawGFIha GdlB/Tud5oo5mNzD8K5FLtWtscMFXYgOhSSSPMgAueJDn52MYhYqVqHwGqV67/xxbP IqS+q+N2AN+sg== Received: from johan by xi.lan with local (Exim 4.98.2) (envelope-from ) id 1wKGlE-00000003Kss-0PKb; Tue, 05 May 2026 16:28:32 +0200 From: Johan Hovold To: Wolfram Sang Cc: Andi Shyti , linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, Johan Hovold , stable@vger.kernel.org, Phil Reid Subject: [PATCH 1/8] i2c: core: fix hang on adapter registration failure Date: Tue, 5 May 2026 16:25:40 +0200 Message-ID: <20260505142547.795054-2-johan@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260505142547.795054-1-johan@kernel.org> References: <20260505142547.795054-1-johan@kernel.org> Precedence: bulk X-Mailing-List: linux-i2c@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Clients may be registered from bus notifier callbacks when the adapter is registered. On a subsequent error during registration, the adapter references taken by such clients prevent the wait for the references to be released from ever completing. Fix this by refactoring client deregistration and deregistering also on late adapter registration failures. Fixes: f8756c67b3de ("i2c: core: call of_i2c_setup_smbus_alert in i2c_register_adapter") Cc: stable@vger.kernel.org # 4.15 Cc: Phil Reid Signed-off-by: Johan Hovold --- drivers/i2c/i2c-core-base.c | 49 ++++++++++++++++++++++--------------- 1 file changed, 29 insertions(+), 20 deletions(-) diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index 9c46147e3506..7cec3f276e13 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -63,6 +63,7 @@ static DEFINE_MUTEX(core_lock); static DEFINE_IDR(i2c_adapter_idr); +static void i2c_deregister_clients(struct i2c_adapter *adap); static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver); static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key); @@ -1605,6 +1606,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap) return 0; out_reg: + i2c_deregister_clients(adap); debugfs_remove_recursive(adap->debugfs); init_completion(&adap->dev_released); device_unregister(&adap->dev); @@ -1744,29 +1746,10 @@ static int __process_removed_adapter(struct device_driver *d, void *data) return 0; } -/** - * i2c_del_adapter - unregister I2C adapter - * @adap: the adapter being unregistered - * Context: can sleep - * - * This unregisters an I2C adapter which was previously registered - * by @i2c_add_adapter or @i2c_add_numbered_adapter. - */ -void i2c_del_adapter(struct i2c_adapter *adap) +static void i2c_deregister_clients(struct i2c_adapter *adap) { - struct i2c_adapter *found; struct i2c_client *client, *next; - /* First make sure that this adapter was ever added */ - mutex_lock(&core_lock); - found = idr_find(&i2c_adapter_idr, adap->nr); - mutex_unlock(&core_lock); - if (found != adap) { - pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name); - return; - } - - i2c_acpi_remove_space_handler(adap); /* Tell drivers about this removal */ mutex_lock(&core_lock); bus_for_each_drv(&i2c_bus_type, NULL, adap, @@ -1792,6 +1775,32 @@ void i2c_del_adapter(struct i2c_adapter *adap) * them up properly, so we give them a chance to do that first. */ device_for_each_child(&adap->dev, NULL, __unregister_client); device_for_each_child(&adap->dev, NULL, __unregister_dummy); +} + +/** + * i2c_del_adapter - unregister I2C adapter + * @adap: the adapter being unregistered + * Context: can sleep + * + * This unregisters an I2C adapter which was previously registered + * by @i2c_add_adapter or @i2c_add_numbered_adapter. + */ +void i2c_del_adapter(struct i2c_adapter *adap) +{ + struct i2c_adapter *found; + + /* First make sure that this adapter was ever added */ + mutex_lock(&core_lock); + found = idr_find(&i2c_adapter_idr, adap->nr); + mutex_unlock(&core_lock); + if (found != adap) { + pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name); + return; + } + + i2c_acpi_remove_space_handler(adap); + + i2c_deregister_clients(adap); /* device name is gone after device_unregister */ dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name); -- 2.53.0