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 A821C35BDC5; Fri, 9 Jan 2026 12:52:07 +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=1767963127; cv=none; b=OeNhLCcg0oxSKFoXq3aYnISSSMQeCqJ4YNRHcMvB8CmdfrmWdcLn1RHpDumxk7+IRUoh3vAzw6+TPN3kYQMzt6yzgYxvF8SK1uuB5FvmlTaZoxbXes7rFx3Z+p3v+IZxsvlT4IegZASbMhSGo+flg/3lQwwUWy+YDos2c9vyJU0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767963127; c=relaxed/simple; bh=8zo6kgnm+u+8Bg0CZJTFqn/Z7+YmJ8GBf19OI6AhFhA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HLvu9/zxXfRQGZ13N9a6GUhJUjW9A3jPr+FsbQotj2bt73Bq5qy+OmddG4QEyb9owaEQI6lMaTuAJbL2ArkJ+nvZgTNhUeMAVTw/aT8skGQ6UgHWMGRWbLeo6+npGPVL2rsIWHxBPsE9yk4qpo1GTLzR5DPGih/dbFr8O3wjqSs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=EM7TS0TH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="EM7TS0TH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 35BC6C4CEF1; Fri, 9 Jan 2026 12:52:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1767963127; bh=8zo6kgnm+u+8Bg0CZJTFqn/Z7+YmJ8GBf19OI6AhFhA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EM7TS0THSQtbCO1hoTwqJRi5/EYpEKUuuOG6FOE3wc0ZXaHTtzGoY2mwLZaM9Qehd Rjgs6ffXatHuRA32Lm4Hk560w60lnNW0xlkMK0In8BNv6Cg1TszBNPj8hBXq+gs5LV wUd1dvIzW1SMmoVmV7RPmfHEZgaaOZ+Ilp8mqgLU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yi Sun , Shuai Xue , Dave Jiang , Vinicius Costa Gomes , Vinod Koul , Bin Lan Subject: [PATCH 6.1 607/634] dmaengine: idxd: Remove improper idxd_free Date: Fri, 9 Jan 2026 12:44:45 +0100 Message-ID: <20260109112140.469719921@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260109112117.407257400@linuxfoundation.org> References: <20260109112117.407257400@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yi Sun [ Upstream commit f41c538881eec4dcf5961a242097d447f848cda6 ] The call to idxd_free() introduces a duplicate put_device() leading to a reference count underflow: refcount_t: underflow; use-after-free. WARNING: CPU: 15 PID: 4428 at lib/refcount.c:28 refcount_warn_saturate+0xbe/0x110 ... Call Trace: idxd_remove+0xe4/0x120 [idxd] pci_device_remove+0x3f/0xb0 device_release_driver_internal+0x197/0x200 driver_detach+0x48/0x90 bus_remove_driver+0x74/0xf0 pci_unregister_driver+0x2e/0xb0 idxd_exit_module+0x34/0x7a0 [idxd] __do_sys_delete_module.constprop.0+0x183/0x280 do_syscall_64+0x54/0xd70 entry_SYSCALL_64_after_hwframe+0x76/0x7e The idxd_unregister_devices() which is invoked at the very beginning of idxd_remove(), already takes care of the necessary put_device() through the following call path: idxd_unregister_devices() -> device_unregister() -> put_device() In addition, when CONFIG_DEBUG_KOBJECT_RELEASE is enabled, put_device() may trigger asynchronous cleanup via schedule_delayed_work(). If idxd_free() is called immediately after, it can result in a use-after-free. Remove the improper idxd_free() to avoid both the refcount underflow and potential memory corruption during module unload. Fixes: d5449ff1b04d ("dmaengine: idxd: Add missing idxd cleanup to fix memory leak in remove call") Signed-off-by: Yi Sun Tested-by: Shuai Xue Reviewed-by: Dave Jiang Acked-by: Vinicius Costa Gomes Link: https://lore.kernel.org/r/20250729150313.1934101-2-yi.sun@intel.com Signed-off-by: Vinod Koul [ Slightly adjust the context. ] Signed-off-by: Bin Lan Signed-off-by: Greg Kroah-Hartman --- Without this patch, this issue can be reproduced in Linux-6.1.y when the idxd module is removed. Signed-off-by: Greg Kroah-Hartman --- drivers/dma/idxd/init.c | 1 - 1 file changed, 1 deletion(-) --- a/drivers/dma/idxd/init.c +++ b/drivers/dma/idxd/init.c @@ -816,7 +816,6 @@ static void idxd_remove(struct pci_dev * destroy_workqueue(idxd->wq); perfmon_pmu_remove(idxd); put_device(idxd_confdev(idxd)); - idxd_free(idxd); } static struct pci_driver idxd_pci_driver = {