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 61D2728DB6C; Fri, 6 Jun 2025 15:44:38 +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=1749224678; cv=none; b=CqGzUeiF//oo01QeZTIE/+071ehenDYsY5tkkWGkVzq16bmDyC6LZfYb7p4BR5ay+YHmVqtGGswMowMRT+SanNebkwkQlyULU8ytfIupNOOBuW8CHHlhBtOJb9jDTJifsx2LMQPSaeHQCi4d2HzUSH4a1JIN6c9e+adLfNtmRF8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749224678; c=relaxed/simple; bh=6Sm7ymWtoHJosH4+YzkKyWHfIGUysELQV0AaRyLsSwI=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=tovzYcs+w6TQelBZZGYeEGyqR2Y7SkavWBpqYd4L7n9iXO7BpaTk9/XN9a6yQt4L/dqO1A3e1tGazl7d/poH2A6rJ8zW+vgslzgbLeJbyxQd7m9ZRTbA2yZE/J2d4pq4/mfz8q1gKA87sPpccy5thOdXCtCXq7q/A8D/N3Fdu/M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UOjQkB2J; 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="UOjQkB2J" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 488DBC4CEF0; Fri, 6 Jun 2025 15:44:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1749224678; bh=6Sm7ymWtoHJosH4+YzkKyWHfIGUysELQV0AaRyLsSwI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UOjQkB2J+RGFxVZmkiw8pMVCNCusqzhQ6Gx2IkGimFdBdgsjoeaMwoQAIFdM2A63o uqs68I0VNC1+tjbN01gRQiK37HL58mYp6s/c+zbdnYd5VyYOQavaQRL0Gh4rhj8CV1 oVC6ErPwMVq7XqXC0PzbYoOZdboHyAToRcihvuHVqkPyeMjTyMIOWYTVrusUix+e98 jdzmasZTj7RRVo9V7pS68EVO1Q5dEmjB1KTlsIioV9oGK4HE6nXRAi9DOmz20tuM+C 0cJxfvmgMBYxC2ETjlAZsKtKAv61lPPjd24RUfnEtvU/s57hvaCc55JcTGk/YCierU BW8QI5+wYxO5w== From: Sasha Levin To: patches@lists.linux.dev, stable@vger.kernel.org Cc: Krzysztof Kozlowski , Lee Jones , Sasha Levin , cw00.choi@samsung.com, krzk@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 3/3] mfd: max14577: Fix wakeup source leaks on device unbind Date: Fri, 6 Jun 2025 11:44:32 -0400 Message-Id: <20250606154433.548697-3-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250606154433.548697-1-sashal@kernel.org> References: <20250606154433.548697-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.4.294 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Krzysztof Kozlowski [ Upstream commit d905d06e64b0eb3da43af6186c132f5282197998 ] Device can be unbound, so driver must also release memory for the wakeup source. Signed-off-by: Krzysztof Kozlowski Link: https://lore.kernel.org/r/20250406-mfd-device-wakekup-leak-v1-3-318e14bdba0a@linaro.org Signed-off-by: Lee Jones Signed-off-by: Sasha Levin --- Now let me understand the difference between the fixes - the historical commits show two patterns: 1. Using `devm_device_init_wakeup()` - automatically handles cleanup 2. Manual cleanup by calling `device_init_wakeup(dev, false)` in remove functions Let me check if this specific commit has `Cc: stable@vger.kernel.org` in the message: Based on my analysis of this commit and comparison with the similar historical commits, here is my assessment: **YES** This commit should be backported to stable kernel trees for the following reasons: ## Analysis ### **Code Change Analysis** The commit adds a single line in the `max14577_i2c_remove()` function: ```c + device_init_wakeup(max14577->dev, false); ``` This addition occurs at drivers/mfd/max14577.c:459, right before `mfd_remove_devices()` is called. ### **Bug Fix Characteristics** 1. **Memory Leak Fix**: The commit fixes a wakeup source memory leak that occurs when the device is unbound. When `device_init_wakeup(dev, true)` is called during probe (line 442), it allocates memory for wakeup source structures. Without the corresponding cleanup call, this memory is leaked on device removal. 2. **Small and Contained**: The fix is minimal - a single line addition that mirrors the cleanup pattern used throughout the kernel. 3. **Low Risk**: The change has extremely low regression risk since it only adds proper cleanup that should have been there originally. ### **Comparison with Historical Similar Commits** Looking at the provided historical commits, there are two categories: **YES commits (backported)**: - `gpio: mpc8xxx: Fix wakeup source leaks on device unbind` - Same exact pattern and includes `Cc: stable@vger.kernel.org` - `gpio: zynq: Fix wakeup source leaks on device unbind` - Same exact pattern and includes `Cc: stable@vger.kernel.org` **NO commits (not backported)**: - IIO driver commits that use `devm_device_init_wakeup()` instead of manual cleanup The key difference is that the YES commits use the same fix pattern as this MFD commit - manual cleanup in the remove function, while the NO commits use the `devm_` managed approach that automatically handles cleanup. ### **Impact Assessment** - **User Impact**: Memory leaks on device unbind affect systems where MFD devices are frequently bound/unbound - **Subsystem**: MFD (Multi-Function Device) is a core kernel subsystem used by many embedded systems - **Regression Risk**: Minimal - adding proper cleanup cannot cause functional regression ### **Stable Tree Criteria Met** 1. ✅ Fixes an important bug (memory leak) 2. ✅ Small and contained change 3. ✅ No architectural changes 4. ✅ Minimal risk of regression 5. ✅ Follows established patterns seen in other backported commits The commit follows the exact same pattern as the GPIO driver commits that were successfully backported to stable trees (commits #1 and #2 in the historical examples), making it a clear candidate for backporting. drivers/mfd/max14577.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/mfd/max14577.c b/drivers/mfd/max14577.c index fd8864cafd25c..4d87b429a7bad 100644 --- a/drivers/mfd/max14577.c +++ b/drivers/mfd/max14577.c @@ -467,6 +467,7 @@ static int max14577_i2c_remove(struct i2c_client *i2c) { struct max14577 *max14577 = i2c_get_clientdata(i2c); + device_init_wakeup(max14577->dev, false); mfd_remove_devices(max14577->dev); regmap_del_irq_chip(max14577->irq, max14577->irq_data); if (max14577->dev_type == MAXIM_DEVICE_TYPE_MAX77836) -- 2.39.5