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 7E7E740099F; Thu, 16 Jul 2026 13:53:37 +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=1784210018; cv=none; b=sskYGoALFf25jIlu+JRcegt8PHwdbbNCY2J+EjsTbFXzKptTBtE96+Yh7i4EO3Dsjy94hrMYYbNkMKLOqxBZczWYqA2FLawvfxEic1xcJkwVMceYp1hWvSHP1y9KXuZXzhGsb9owo738tAy4sLbchf+GfH1aEhfYuktxbESidAw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784210018; c=relaxed/simple; bh=FMVwlOeo/TldH8ppkoASyfFclwAIWW+Ax6vDeoSrRzc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OeuwScj+M8NYpN/5xV4jQNktDS2260yOTVYQcCuzkMg9yBIph9GkyQdsbeyv9G126xWQs5TCSDYIsY1lcb+psqPbaYUZjTlHAuEXFxoNwmufqdujyseel6x1nxKyKvU3X98fQUYo5i8H23qbSOGxRu9LMW0iMnsM9Imt2keNZ00= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=TzjQkDHm; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="TzjQkDHm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CEC281F000E9; Thu, 16 Jul 2026 13:53:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784210017; bh=MwxRg7bzIEogAIcgFSozc+qOySAdw81x2zidET5FGKk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=TzjQkDHmtAoL1IE1kZxuSFgpp0QjqJtKWeVSla4tjJGNFEN+cWc/ckl/RVHlBYKoQ PMFmPgGw/8F969dMicP1Y1hHeFpYIfMRqqzUFrbljM0MgHoiLvwBTa5IqsB+HT4gnO K7Yqhc1TH+9GKONSkPgI027XcH9/XpRV+zW5alTw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Phil Reid , Johan Hovold , Wolfram Sang Subject: [PATCH 7.1 407/518] i2c: core: fix hang on adapter registration failure Date: Thu, 16 Jul 2026 15:31:15 +0200 Message-ID: <20260716133056.740610014@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260716133047.772246337@linuxfoundation.org> References: <20260716133047.772246337@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Johan Hovold commit 3c7e164344e5bcf6f274bbf59a3274f5caad9bc1 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- drivers/i2c/i2c-core-base.c | 49 ++++++++++++++++++++++++++------------------ 1 file changed, 29 insertions(+), 20 deletions(-) --- 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); @@ -1608,6 +1609,7 @@ static int i2c_register_adapter(struct i return 0; out_reg: + i2c_deregister_clients(adap); debugfs_remove_recursive(adap->debugfs); init_completion(&adap->dev_released); device_unregister(&adap->dev); @@ -1747,29 +1749,10 @@ static int __process_removed_adapter(str 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, @@ -1795,6 +1778,32 @@ void i2c_del_adapter(struct i2c_adapter * 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);