[{"id":3676550,"web_url":"http://patchwork.ozlabs.org/comment/3676550/","msgid":"","list_archive_url":null,"date":"2026-04-13T08:21:40","subject":"Re: [PATCH 4/5] staging: nvec: fix pm_power_off teardown in\n tegra_nvec_remove()","submitter":{"id":389,"url":"http://patchwork.ozlabs.org/api/people/389/","name":"Dan Carpenter","email":"error27@gmail.com"},"content":"On Sun, Apr 12, 2026 at 10:51:17PM +0200, Alexandru Hossu wrote:\n> The remove() function unconditionally sets pm_power_off to NULL regardless\n> of whether this driver instance was the one that set it. There is even a\n> FIXME comment acknowledging this. Additionally, nvec_power_handle is never\n> cleared on removal, leaving a dangling pointer to freed device data.\n> \n> Fix both issues: check that pm_power_off still points to nvec_power_off\n> before clearing it, and also clear nvec_power_handle at the same time.\n> \n> Signed-off-by: Alexandru Hossu \n> ---\n> drivers/staging/nvec/nvec.c | 6 ++++--\n> 1 file changed, 4 insertions(+), 2 deletions(-)\n> \n> diff --git a/drivers/staging/nvec/nvec.c b/drivers/staging/nvec/nvec.c\n> index 75877038847f..9fe9b7a3491d 100644\n> --- a/drivers/staging/nvec/nvec.c\n> +++ b/drivers/staging/nvec/nvec.c\n> @@ -907,8 +907,10 @@ static void tegra_nvec_remove(struct platform_device *pdev)\n> \tnvec_unregister_notifier(nvec, &nvec->nvec_status_notifier);\n> \tcancel_work_sync(&nvec->rx_work);\n> \tcancel_work_sync(&nvec->tx_work);\n> -\t/* FIXME: needs check whether nvec is responsible for power off */\n> -\tpm_power_off = NULL;\n> +\tif (pm_power_off == nvec_power_off) {\n> +\t\tpm_power_off = NULL;\n> +\t\tnvec_power_handle = NULL;\n> +\t}\n\nLinux power off handling is a known mess...\n\nI wonder why the original added a comment instead of a test? To me\nchecking for if if (pm_power_off == nvec_power_off) makes sense and I\ncan't see how it would hurt anything.\n\nAt this point, we're unloading the driver so nvec_power_handle is\nabout to be freed. Is there any benefit to setting it to NULL?\n\nregards,\ndan carpenter","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-tegra@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256\n header.s=20251104 header.b=WsQWyFya;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=172.232.135.74; helo=sto.lore.kernel.org;\n envelope-from=linux-tegra+bounces-13738-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com\n header.b=\"WsQWyFya\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=209.85.128.45","smtp.subspace.kernel.org;\n dmarc=pass (p=none dis=none) header.from=gmail.com","smtp.subspace.kernel.org;\n spf=pass smtp.mailfrom=gmail.com"],"Received":["from sto.lore.kernel.org (sto.lore.kernel.org [172.232.135.74])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519 server-signature ECDSA (secp384r1) server-digest SHA384)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fvL3j5P0dz1yDF\n\tfor ; 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