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 E77F91ACEDF; Wed, 4 Jun 2025 01:06:50 +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=1748999211; cv=none; b=k6/k0r6YskhUcikPuD15ZpeftlWaCY2XRaeoRLFr4z0dLzGEej0osTWUMZpuLgFOWDNN18dIQlK53z0qcsbPLhZD2gpgeb52+v27kavOSG8OyS4EZ+fqP8ol8B4f8VE5zlGQHEoXavpHSmLX9SMU72kwZ54e1tunul4zWUpytVg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748999211; c=relaxed/simple; bh=FfVoUlRrOeVuivnq1WtG+P0Gc1+++mk6EguKJxkbs2Q=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=kCesDevVlzHsTr7Ya1WDQqGq9UeBFQ8SCe9Oaiq1/99DWFiJ+76XKvDmn+SlR+pvhe45i4AV7iuxVD0ma5+3KlPhzw1de2Eenb2cWuyjD7gKFu2lWbiUTKpeKsmdRQCAikicJa29a1Pnhui1quPxuL31Lrn7irpfB3rU4qa5FvE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZY3Kg+Dp; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZY3Kg+Dp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 77A4EC4CEF2; Wed, 4 Jun 2025 01:06:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1748999210; bh=FfVoUlRrOeVuivnq1WtG+P0Gc1+++mk6EguKJxkbs2Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZY3Kg+DpgZbiK35rvBd5ERHJM712QXoDIAt+ofw2mVMtw3ugVgcnQvVk10l+7l6CY xbDr/wzynU3tUajYeU2KhMMnaZJOVZgKdb9KQg9VeqlUjyZ75uxgry6dpFtoQpyAnl IY0jnpDxTEjNX+Te6Aj5r8haMmAmwMMmQAxxF0HUzuKcHk9C0xNO+2aGlJ+9moY6oU 7U6PS6mrRK2UnbMXaiRZMvlLeXg4Wzt06Gdb/eIeyOzFmAEwEkrv3xzfn6KFH6ZJWB P103zuVk1HtMzJjBNYqQgZIujAOtB7WK/bzPsaZhl93XE4Yn8PYQdUs5ZRdhbmTv/B HC+OvS4sguTlg== From: Sasha Levin To: patches@lists.linux.dev, stable@vger.kernel.org Cc: Gabor Juhos , Imre Kaloz , Andrew Lunn , Linus Walleij , Sasha Levin , gregory.clement@bootlin.com, sebastian.hesselbarth@gmail.com, brgl@bgdev.pl, linux-arm-kernel@lists.infradead.org, linux-gpio@vger.kernel.org Subject: [PATCH AUTOSEL 5.10 17/27] pinctrl: armada-37xx: propagate error from armada_37xx_gpio_get() Date: Tue, 3 Jun 2025 21:06:10 -0400 Message-Id: <20250604010620.6819-17-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250604010620.6819-1-sashal@kernel.org> References: <20250604010620.6819-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.10.237 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Gabor Juhos [ Upstream commit 57273ff8bb16f3842c2597b5bbcd49e7fa12edf7 ] The regmap_read() function can fail, so propagate its error up to the stack instead of silently ignoring that. Signed-off-by: Imre Kaloz Reviewed-by: Andrew Lunn Signed-off-by: Gabor Juhos Link: https://lore.kernel.org/20250514-pinctrl-a37xx-fixes-v2-4-07e9ac1ab737@gmail.com Signed-off-by: Linus Walleij Signed-off-by: Sasha Levin --- Based on my comprehensive analysis, here is my determination: **YES** This commit should be backported to stable kernel trees. Here's my detailed analysis: ## Analysis of the Code Change The commit fixes a clear bug in the `armada_37xx_gpio_get()` function in `drivers/pinctrl/mvebu/pinctrl-armada-37xx.c`. The specific changes are: 1. **Before**: `regmap_read(info->regmap, reg, &val);` - ignores return value 2. **After**: `ret = regmap_read(info->regmap, reg, &val); if (ret) return ret;` - properly handles errors ## Backport Suitability Assessment ### ✅ **Meets Stable Tree Criteria:** 1. **Bug Fix**: This clearly fixes a real bug where regmap read failures are silently ignored, potentially returning garbage data to userspace. 2. **Small and Contained**: The change is minimal (3 lines added) and extremely focused, affecting only error handling in a single function. 3. **Low Regression Risk**: The change only adds error checking where none existed before. It cannot introduce new bugs - it can only prevent incorrect behavior. 4. **No Architectural Changes**: This is purely error handling improvement with no changes to the driver's architecture or interfaces. 5. **Important Subsystem**: GPIO operations are fundamental and used by many kernel subsystems and userspace applications. ### ✅ **Follows Established Kernel Patterns:** My analysis of other GPIO drivers shows this error handling pattern is **universal** across the kernel: - `gpio-arizona.c`, `gpio-bd71828.c`, `gpio- madera.c`, `gpio-max77620.c`, `pinctrl-axp209.c`, and many others - **Every examined driver** checks `regmap_read` return values in GPIO get functions - The armada-37xx driver was an outlier in ignoring these errors ### ✅ **Real-World Impact:** This fix addresses scenarios where: - **Hardware communication failures** (I2C/SPI bus errors, device power issues) - **Device disconnect events** (hot-plug scenarios, power management) - **Timing/electrical issues** causing intermittent regmap failures Without this fix, `gpio_get()` would return potentially garbage values (using uninitialized `val`) when hardware communication fails, leading to incorrect GPIO state reporting to userspace. ### ✅ **Reference Similar Commits:** Looking at the provided examples, this commit closely resembles: - **Similar Commit #3 (Status: YES)**: "Fix irq_of_parse_and_map() return value" - fixes incorrect error handling - **Similar Commit #1 (Status: YES)**: "Convert to use dev_err_probe()" - improves error handling patterns Both are small, focused error handling improvements that were deemed suitable for backporting. ## Conclusion This is a textbook example of a stable tree candidate: it's a small, safe bug fix that brings the driver in line with kernel-wide error handling standards, addresses real hardware failure scenarios, and has zero risk of regression while providing tangible benefits for system reliability. drivers/pinctrl/mvebu/pinctrl-armada-37xx.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/pinctrl/mvebu/pinctrl-armada-37xx.c b/drivers/pinctrl/mvebu/pinctrl-armada-37xx.c index 0f799faf84c78..c9b2ef70ddc7c 100644 --- a/drivers/pinctrl/mvebu/pinctrl-armada-37xx.c +++ b/drivers/pinctrl/mvebu/pinctrl-armada-37xx.c @@ -437,11 +437,14 @@ static int armada_37xx_gpio_get(struct gpio_chip *chip, unsigned int offset) struct armada_37xx_pinctrl *info = gpiochip_get_data(chip); unsigned int reg = INPUT_VAL; unsigned int val, mask; + int ret; armada_37xx_update_reg(®, &offset); mask = BIT(offset); - regmap_read(info->regmap, reg, &val); + ret = regmap_read(info->regmap, reg, &val); + if (ret) + return ret; return (val & mask) != 0; } -- 2.39.5