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 E5E1A273D9F for ; Thu, 28 May 2026 13:49:33 +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=1779976175; cv=none; b=Ou8cdEX3PHKdlxPaRsr3szEEV0utsYTX8kbKQw+tTVJiNngaeWTGw7DkmNgDau2cC0ZFJYzXRzRPNI9hAe3cBmU73EgYZoAf6Iag4g4z/wrtzQ4hJCkAxbgHOlRwmjrg68GJaagAVrTCGvMr2cPEq0SQJARiu7Leisw5Fptn9Hg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779976175; c=relaxed/simple; bh=gfQ/gDw0bdJRBPmy1kG4VhztZYgvKzso6DDxBg76vTk=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=StxMW7kkz9ZYmBKtlM5vlNTaCpJrSUiSpN1kSJrafZRB76PUjTkCG0G/7qj98ov/Qpu8sNfuFUAdlEBt4Ruaxn0b7oP8k8THDYLA49wWIM4r5YjWaD2HYVxyYCeNfLJ0lzG+HNeehogBNR3o3rM+f0BF0uYrIeS/YXGUdozCyis= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=GpC3tdeK; 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="GpC3tdeK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1339F1F000E9; Thu, 28 May 2026 13:49:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779976173; bh=OgGpTyyqzpLDHY5/bAHpCq/7p46eRCwhwi02HGst5qA=; h=Subject:To:Cc:From:Date; b=GpC3tdeKjWL6HPi0DZoT7dsDbH/3zqVV4AgTPuCIqvZVFMrlbOI5Y3gsuhqJ4a89F IlGDbO4N8IDKGp7P0M8WAkJM1drmGQNzB7FYjZivtYJyCNglGvAkv2SqJOMYQHbFq8 MxOwwjcjN3HxIuYUxkDiDrJGRSv2wuUHeuqFezG8= Subject: FAILED: patch "[PATCH] hwmon: (pmbus/adm1266) serialize NVMEM blackbox read with" failed to apply to 6.18-stable tree To: abdurrahman@nexthop.ai,linux@roeck-us.net Cc: From: Date: Thu, 28 May 2026 15:48:30 +0200 Message-ID: <2026052830-amicably-spoon-d982@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 6.18-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-6.18.y git checkout FETCH_HEAD git cherry-pick -x 9f1dd8f9491eb840cbea7ffdf4cad031e25f8ae0 # git commit -s git send-email --to '' --in-reply-to '2026052830-amicably-spoon-d982@gregkh' --subject-prefix 'PATCH 6.18.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 9f1dd8f9491eb840cbea7ffdf4cad031e25f8ae0 Mon Sep 17 00:00:00 2001 From: Abdurrahman Hussain Date: Mon, 18 May 2026 17:52:31 -0700 Subject: [PATCH] hwmon: (pmbus/adm1266) serialize NVMEM blackbox read with pmbus_lock adm1266_nvmem_read() is the reg_read callback the NVMEM core invokes when userspace reads /sys/bus/nvmem/devices/.../nvmem on this chip. On the first byte of every read it does a memset of data->dev_mem, walks the device blackbox through adm1266_nvmem_read_blackbox() (which issues a chain of PMBus block transactions), and then memcpys the refreshed buffer out to userspace. None of that runs under pmbus_lock today. Two consequences: - The PMBus traffic the refresh issues is not serialised against pmbus_core's own multi-step PAGE+register sequences. A paged hwmon attribute read from another thread can land between a PAGE write and the paged read in either direction and corrupt one side's view of the device state machine. - The NVMEM core does not serialise concurrent reg_read calls, so two userspace readers racing at offset 0 can interleave the memset of data->dev_mem with another reader's adm1266_nvmem_read_blackbox() refill or memcpy out, returning torn data to userspace. Take pmbus_lock at the top of adm1266_nvmem_read() via the scope-based guard(). Patch 5 of this series moves adm1266_config_nvmem() past pmbus_do_probe() so the lock is guaranteed to be live before the callback is reachable from userspace. Fixes: 15609d189302 ("hwmon: (pmbus/adm1266) read blackbox") Cc: stable@vger.kernel.org Signed-off-by: Abdurrahman Hussain Link: https://lore.kernel.org/r/20260518-adm1266-gpio-fixes-v3-7-e425e4f88139@nexthop.ai Signed-off-by: Guenter Roeck diff --git a/drivers/hwmon/pmbus/adm1266.c b/drivers/hwmon/pmbus/adm1266.c index 0eef58dd69a6..5ddca5701032 100644 --- a/drivers/hwmon/pmbus/adm1266.c +++ b/drivers/hwmon/pmbus/adm1266.c @@ -400,6 +400,8 @@ static int adm1266_nvmem_read(void *priv, unsigned int offset, void *val, size_t if (offset + bytes > data->nvmem_config.size) return -EINVAL; + guard(pmbus_lock)(data->client); + if (offset == 0) { memset(data->dev_mem, 0, data->nvmem_config.size);