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 9D85539A7FE for ; Tue, 29 Sep 2026 06:48:17 +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=1790664498; cv=none; b=gUKNoOzCFK2Pg4KgHBX/1JLBuPbatGyOUpPXVWFjEfHbJJ9E11Xb+LoygNCZUHB3KEP/VmVXJ3Xuifj3bu5VQw+g9PZ1ojktGrRkcV7Fbn1QwC+m4X8DmhfWylmW6HoKAnA4d1UllGDXTrdUgQVo77l1yGBDvdFcqd9rQSLBvBQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790664498; c=relaxed/simple; bh=L9SleVf0Gzc9yJUVbg/YZUQR3sk0bI804Kgh5SH2G0I=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=PkaXguou5sltbh7SA7iEWHjSfrmIRx89CbhuTjkk31dyev0N+EffXHfwQ+g0p3qTyz4XLj6sR9quGj3McQxU+oWeptGTFEv/bPHPAARfs8V/RQTKhpPKXQ8uyBjH1E6FiiZ6kjxZ7/MHDATvMMH6reRpnn4NNLRHDkCFJMq/dAI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=xyL2T2gP; 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="xyL2T2gP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EBEC81F000FF; Tue, 29 Sep 2026 06:48:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790664497; bh=aLpHt1cdSiwShZTbofMz50czhrgL/JK7g0jbYJh189A=; h=Subject:To:Cc:From:Date; b=xyL2T2gPOnFaEPUOB3mUxq5xoSsITgiYx5k02Sl7RAnyUK8BI5NwAfsovIZOrDZpD FRQ0GRohE0p7bSGXZGwPyfuKAVgoGQqVtnkiNzAOHQ7heTmdT9kkFoYr3zdRq+QkbR +XNCLXR0F+GpJllhc9tiG+J7swrEh5LvPP5Jadfs= Subject: FAILED: patch "[PATCH] gpio: cdev: fix kernel stack leak to user-space in error path" failed to apply to 6.12-stable tree To: bartosz.golaszewski@oss.qualcomm.com,sashiko-bot@kernel.org,warthog618@gmail.com Cc: From: Date: Tue, 29 Sep 2026 08:48:14 +0200 Message-ID: <2026092914-tipping-waviness-6ae5@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x 1feb5d39b05afd902ed9fc902ec5b15be03a4bdb # git commit -s git send-email --to '' --in-reply-to '2026092914-tipping-waviness-6ae5@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 1feb5d39b05afd902ed9fc902ec5b15be03a4bdb Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Tue, 22 Sep 2026 10:52:28 +0200 Subject: [PATCH] gpio: cdev: fix kernel stack leak to user-space in error path If we fail to acquire the GPIO chip guard in gpio_desc_to_lineinfo(), we return immediately before zeroing the info struct we'll end up passing to the user-space later in lineinfo_get_v1(). This may leak the kernel stack contents. Make gpio_desc_to_lineinfo() return int so that the -ENODEV returned on failure to acquire the guard can be propagated to the callers. While not strictly necessary: move the memset() before trying to acquire the SRCU read lock too for good measure. Fixes: d83cee3d2bb1 ("gpio: protect the pointer to gpio_chip in gpio_device with SRCU") Cc: stable@vger.kernel.org Reported-by: Sashiko Closes: https://sashiko.dev/#/patchset/20260912123529.7951-1-tzungbi%40kernel.org?part=3 Reviewed-by: Kent Gibson Link: https://patch.msgid.link/20260922-gpio-cdev-stack-leak-fixes-v3-1-7a0c7a4299d5@oss.qualcomm.com Signed-off-by: Bartosz Golaszewski diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index d1105b7ae437..5d53bfcdf726 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -2172,18 +2172,19 @@ static void gpio_v2_line_info_changed_to_v1( #endif /* CONFIG_GPIO_CDEV_V1 */ -static void gpio_desc_to_lineinfo(struct gpio_desc *desc, - struct gpio_v2_line_info *info, bool atomic) +static int gpio_desc_to_lineinfo(struct gpio_desc *desc, + struct gpio_v2_line_info *info, bool atomic) { u32 debounce_period_us; unsigned long dflags; const char *label; + memset(info, 0, sizeof(*info)); + CLASS(gpio_chip_guard, guard)(desc); if (!guard.gc) - return; + return -ENODEV; - memset(info, 0, sizeof(*info)); info->offset = gpiod_hwgpio(desc); if (desc->name) @@ -2258,6 +2259,8 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc, debounce_period_us; info->num_attrs++; } + + return 0; } struct gpio_chardev_data { @@ -2309,6 +2312,7 @@ static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip, struct gpio_desc *desc; struct gpioline_info lineinfo; struct gpio_v2_line_info lineinfo_v2; + int ret; if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) return -EFAULT; @@ -2326,7 +2330,10 @@ static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip, return -EBUSY; } - gpio_desc_to_lineinfo(desc, &lineinfo_v2, false); + ret = gpio_desc_to_lineinfo(desc, &lineinfo_v2, false); + if (ret) + return ret; + gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo); if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { @@ -2344,6 +2351,7 @@ static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip, { struct gpio_desc *desc; struct gpio_v2_line_info lineinfo; + int ret; if (copy_from_user(&lineinfo, ip, sizeof(lineinfo))) return -EFAULT; @@ -2363,7 +2371,10 @@ static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip, if (test_and_set_bit(lineinfo.offset, cdev->watched_lines)) return -EBUSY; } - gpio_desc_to_lineinfo(desc, &lineinfo, false); + + ret = gpio_desc_to_lineinfo(desc, &lineinfo, false); + if (ret) + return ret; if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { if (watch) @@ -2489,6 +2500,7 @@ static int lineinfo_changed_notify(struct notifier_block *nb, struct lineinfo_changed_ctx *ctx; struct gpio_desc *desc = data; struct file *fp; + int ret; if (!test_bit(gpiod_hwgpio(desc), cdev->watched_lines)) return NOTIFY_DONE; @@ -2519,7 +2531,13 @@ static int lineinfo_changed_notify(struct notifier_block *nb, ctx->chg.event_type = action; ctx->chg.timestamp_ns = ktime_get_ns(); - gpio_desc_to_lineinfo(desc, &ctx->chg.info, true); + + ret = gpio_desc_to_lineinfo(desc, &ctx->chg.info, true); + if (ret) { + fput(fp); + return NOTIFY_DONE; + } + /* Keep the GPIO device alive until we emit the event. */ ctx->gdev = gpio_device_get(desc->gdev); ctx->cdev = cdev;