From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 B598B370D79 for ; Sun, 5 Jul 2026 13:48:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783259283; cv=none; b=EWgKK3MznxC9WbTAPdWGnfo/VrJwswLn81QEF1Jt7kFzkF+mc5ojcyluR7SpcWcpEUYFs+GF6RL0unS0tJhS5pp+z7uz9z94hvOhyZlv3nBt4NA4dJ3LCdu7GyrKaMv8kqAPkZIGN04Hr3a4x48hGSX5lZIZ3D+lU467iKTlVU8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783259283; c=relaxed/simple; bh=NaT9W322RtRaAVsmYNLvpBuYQRuE3Ek01AqrMR2z4cM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Q8yXxLdjxW1uuG5XkmRfOIgQFJFIfIQ4AuCk14EGq9sh/uHnZntHts1CIs6xsEfGxPGGvCcnfNmkaU7VN8RUzT8k9SSG9qZVTm1Q41NRqdJsmKt8rXhIaOkTkL4NBeBH26A0ZRteLH9avGc/roffFPEMHl8DN+fD/CpUAXjcMFY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZSkOt4Jh; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZSkOt4Jh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E88511F00A3A; Sun, 5 Jul 2026 13:48:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783259282; bh=znKlYNfrp/xPJcbL2JnMJ9+PKAwG2jiCZMXfzYo566k=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ZSkOt4Jh7SbX+DOcy6OtsttTFhhW3cVpZf4V0aPletG2bbvQfR9BnkVISMGZonJg1 hdswCnA5pj8Cjzq3eaEPjNFmngM0oyONop/v8xHXv8S0jDoepCF0co5p2oSAn0RvSG uNIABC+s0JcaCJKOixxtaBfThlyetk4NMoD46awUhDg8SG4sqIYiywEKCYZJM27E1H HFL/oNs4HISZygUhrQDc0Lh42S1FdexmG1avGyp92ieRmt7wxZt5+LcvNvetSxBX4A 51b8jbbfFZVnnuZa0629H/KdbgptY8foZ0/iX2rz6FebF49GOd3mid+EHzVvnrtbfK W6HGWu2RFJ+Kw== From: Sasha Levin To: stable@vger.kernel.org Cc: Johan Hovold , Phil Reid , Wolfram Sang , Sasha Levin Subject: [PATCH 6.1.y 2/5] i2c: core: fix hang on adapter registration failure Date: Sun, 5 Jul 2026 09:47:56 -0400 Message-ID: <20260705134759.1722831-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260705134759.1722831-1-sashal@kernel.org> References: <2026070232-jet-sheep-e8a6@gregkh> <20260705134759.1722831-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Johan Hovold [ Upstream commit 3c7e164344e5bcf6f274bbf59a3274f5caad9bc1 ] 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 Signed-off-by: Wolfram Sang Stable-dep-of: ba14d7cf2fe7 ("i2c: core: fix adapter registration race") Signed-off-by: Sasha Levin --- 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 e639c679d2737e..8d688d631ccbfe 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -62,6 +62,7 @@ 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); @@ -1600,6 +1601,7 @@ 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); @@ -1743,29 +1745,10 @@ 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, @@ -1791,6 +1774,32 @@ 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); #ifdef CONFIG_I2C_COMPAT class_compat_remove_link(i2c_adapter_compat_class, &adap->dev, -- 2.53.0