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 6CDA82DF134 for ; Thu, 16 Jul 2026 12:42:58 +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=1784205779; cv=none; b=VhKtMafxa7Q/RNU0W/yeTkYljGZinZdoH0UZ8VsjYwK0jyuFtUsH4Ka72P4OcU0kan+bZsm0s+dQj1BEfdYywJY3+azhuItipOuagSXeit8ym7sypsurkXk4JuuKBaLMy/3jwcmc6gPomJk+hEIwoUuFdsJzJ5ECc4IuMc45x1c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784205779; c=relaxed/simple; bh=C7odCVjCERXzRbvCK4N7dd/JoVlhWz8uMsKI32wIfIc=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=LFw55fReo16YUD9IttFi6cVl8nqUr/J/SjarbwJJH94W71WAYdF0ZF2j2D/cdBEuUGxng/cNN2y1/6oM6s0l9VyMLlSN7j+ZeuHecyghuH1VvwOMgtkTrVz4rXBS0ghcndYAIkmsQi72YXg+wbqLsFw2RRhVjU7lVSWd9WI0VhY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=OEv7MZvS; 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="OEv7MZvS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8DA6B1F00A3A; Thu, 16 Jul 2026 12:42:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784205778; bh=tRG97W1iURJ7VBfdNUvsXd6b7HvKo8s536jMJQIXD5o=; h=Subject:To:Cc:From:Date; b=OEv7MZvS7yHpOUApYJfXKzrD0nF7BNXC+ys233ET2L+ieF44/Z9W2F/jo3eZMgPY1 kulxsCxb8RjzSqohgs9lz+0N07jmakYKdZAtd4JdFt49FckrueEayzTm8N61xVnRL/ IIjH0FciymdMs+0kKQMq5Ua+veXgnUWKFWfNVLlo= Subject: FAILED: patch "[PATCH] i2c: i801: fix hardware state machine corruption in error" failed to apply to 6.6-stable tree To: 25181214217@stu.xidian.edu.cn,andi.shyti@kernel.org,stable@vger.kernel.org Cc: From: Date: Thu, 16 Jul 2026 14:42:43 +0200 Message-ID: <2026071643-unnoticed-jitters-56c2@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 6.6-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-6.6.y git checkout FETCH_HEAD git cherry-pick -x 10dd1a736d557e310a77117832874729a0175d57 # git commit -s git send-email --to '' --in-reply-to '2026071643-unnoticed-jitters-56c2@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 10dd1a736d557e310a77117832874729a0175d57 Mon Sep 17 00:00:00 2001 From: Mingyu Wang <25181214217@stu.xidian.edu.cn> Date: Tue, 12 May 2026 17:35:34 +0800 Subject: [PATCH] i2c: i801: fix hardware state machine corruption in error path A severe livelock and subsequent Hung Task panic were observed in the i2c-i801 driver during concurrent Fuzzing. The crash is caused by an unconditional hardware register cleanup in the error handling path of i801_access(). When i801_check_pre() fails (e.g., returning -EBUSY because the SMBus controller is actively used by BIOS/ACPI), the kernel does not actually acquire the hardware ownership. However, the code jumps to the 'out' label and executes: iowrite8(SMBHSTSTS_INUSE_STS | STATUS_FLAGS, SMBHSTSTS(priv)); This forcefully clears the INUSE_STS lock and resets the hardware status flags without owning the controller. Doing so interrupts ongoing BIOS/ACPI transactions and totally corrupts the SMBus hardware state machine. Consequently, all subsequent i801_access() calls fail at the pre-check stage, triggering an endless stream of "SMBus is busy, can't use it!" error logs. Over a slow serial console, this printk flood monopolizes the CPU (Console Livelock), starving other processes trying to acquire the mmap_lock down_read semaphore, ultimately triggering the hung task watchdog. Fix this by moving the 'out' label below the hardware register cleanup. If i801_check_pre() fails, we safely bypass the iowrite8() and only release the software locks (pm_runtime and mutex), strictly adhering to the rule of not releasing resources that were never acquired. Fixes: 1f760b87e54c ("i2c: i801: Call i801_check_pre() from i801_access()") Signed-off-by: Mingyu Wang <25181214217@stu.xidian.edu.cn> Cc: # v6.3+ Signed-off-by: Andi Shyti Link: https://lore.kernel.org/r/20260512093534.348655-1-w15303746062@163.com diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index 32a3cef02c7b..b29c99ed3883 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -931,13 +931,13 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr, */ if (hwpec) iowrite8(ioread8(SMBAUXCTL(priv)) & ~SMBAUXCTL_CRC, SMBAUXCTL(priv)); -out: /* * Unlock the SMBus device for use by BIOS/ACPI, * and clear status flags if not done already. */ iowrite8(SMBHSTSTS_INUSE_STS | STATUS_FLAGS, SMBHSTSTS(priv)); +out: pm_runtime_put_autosuspend(&priv->pci_dev->dev); mutex_unlock(&priv->acpi_lock); return ret;