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 74B1C26B973 for ; Sun, 5 Jul 2026 19:06:15 +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=1783278376; cv=none; b=dcEDKhOFWwj3yFwnc/e6NAF0PIn0cHE6vd82TMbwj4sxtFwTRYkAHaiLzFiWbnS0djKhjjGkOizKhU6eukj71E28yO2V/66djg7FxHCvAIEP7CB4gqpJBjSO5vgR2/yEMt6gXJY+hB+6o7sVUiWU8Gpac9VmE+oQ5nKgJ+7NZCI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783278376; c=relaxed/simple; bh=29oWDHLxmXP9SdQMDXDDLcxX4V6t+iuCrbPKc0nhHm0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cR4Ao5Wr/C+tF0vNMvQI2qhLi5hOy4m5yLtlxefcZrAdEMqW/ZshMeHkW5QF5b+pMmIWRRWZ4AAWOhhy6T3+72SACsA6ix0OnXtUX2QtEm7iWL30wsJ+RC9QNKD3fOXpCOpQxsAsvZbfMZCbwbbZRapISuNLPAoDZ4Wkki4YTb4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PRJmAk1q; 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="PRJmAk1q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 84C861F00A3D; Sun, 5 Jul 2026 19:06:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783278375; bh=MHI2dAm2x7n6BX7V0YsuE1cPD1zwW7xQ2WKmeOFj/XA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=PRJmAk1qYoS4KzGVxEcrf0s6PSGQOq1NwyCFVkvK7joJRS1scAPqm5/VusTyLPqT2 8yazI8LngdhUoHoQjwK4p3+qXfOHQV0wK1Zcge/mhgsMpPMkcWA7V4Mxm0wBwaSxtt A25x4mfB8hjNqK3750cAZOxeqbloW8lc0dQH9dvnGa1Ix4/8z6RUjfL8KXsbGFSsIc U6QRGjaJp9XfSBp0kEo2o7SHdpsmgg3sLJiIyYGBg1gDfeukjHIPK++nG7vAoDU9fJ EWvg1RoiQgcm77axz20G7FHVF+oovnI1TtIAbObSbZGLBV9/fwtfxZSpqDlODIhLeS XC4yxuVdtcZdA== From: Sasha Levin To: stable@vger.kernel.org Cc: Johan Hovold , Phil Reid , Wolfram Sang , Sasha Levin Subject: [PATCH 5.10.y 2/5] i2c: core: fix hang on adapter registration failure Date: Sun, 5 Jul 2026 15:06:09 -0400 Message-ID: <20260705190612.1987801-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260705190612.1987801-1-sashal@kernel.org> References: <2026070233-lushly-episode-a47f@gregkh> <20260705190612.1987801-1-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 bbb4c8a3d4a6fa..8abd576d357b67 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -61,6 +61,7 @@ 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); @@ -1502,6 +1503,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap) return 0; out_reg: + i2c_deregister_clients(adap); init_completion(&adap->dev_released); device_unregister(&adap->dev); wait_for_completion(&adap->dev_released); @@ -1644,29 +1646,10 @@ 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, @@ -1692,6 +1675,32 @@ 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