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 1AB1C8248B for ; Tue, 2 Jun 2026 11:18:27 +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=1780399110; cv=none; b=NtgLzFRTr/WT24O1TsajlADGWNQhGV1HodnFH4surcXcfnEkKLR1ijeHEyVmPjH81f7YQPc99SqtEN0wFDaS1gsJPwhZgFtByH+fh2nT+kwvqb3YaPSwkFjD1iXZDY2XrBZWWFxWHvpcL+OtsdI1H8TWWoyqk4yt/4RJiiiBB48= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780399110; c=relaxed/simple; bh=kr7KOp1qE3yXrCDCS5SUTK5Q2Blq06QYsCAg/qbr+N8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=E2D6l2KvifFNqlW49r/o8wOrRRQwPTQ/cRE9PXaQ4U/ubVEDnXeEEpWqb7MSoxhwN8EDeNNvy+tCJmi30rDs1IcIrTcEkw32L2mvKVU+UDjb5DlBvIwk8Pia/THIEye2HbnHVSksgsXCEETWU7q9hSFXZs8kX/91xGnetPKHZoc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=i/TnlJm+; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="i/TnlJm+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E85E41F00898; Tue, 2 Jun 2026 11:18:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780399107; bh=q3zw2w9lAwexKKQWE91f+PQx0foacpyzQu5XkZ0ON38=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=i/TnlJm+Vw0BukAxcauOcaQP9f8zoZROcTUpyL5OnCdf/9DUCeN+J+cLpec/X+zIA TbCojF8cYMDBWQpO484ruqpTAdlK0QgCY6R+p9gF52KJRZCVuO0amead2T4hxBzNqK 3jGqa7d3iUWTvJTzqBkKjO4HKqi7yEZ2Xtp9e/ZRDonugXN6HXVV6CGRtpPprKxVHO h1LWRQezWTl8K7dGNX9coACXxyXht5iovTWKPuDEFrIIibESHdxm6Z52GnCvrvV4P3 f1D2a7tfGVUNfpn1O4cKy4UJAvuc+umcRx+4sDqJ8LAuAz86Ot4XDPfp9G1//cRW2d RMAQsnK5hXbxA== From: Sasha Levin To: stable@vger.kernel.org Cc: Abdurrahman Hussain , Guenter Roeck , Sasha Levin Subject: [PATCH 6.1.y] hwmon: (pmbus/adm1266) serialize NVMEM blackbox read with pmbus_lock Date: Tue, 2 Jun 2026 07:18:25 -0400 Message-ID: <20260602111825.1305810-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026052847-broadcast-elevating-8bc4@gregkh> References: <2026052847-broadcast-elevating-8bc4@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Abdurrahman Hussain [ Upstream commit 9f1dd8f9491eb840cbea7ffdf4cad031e25f8ae0 ] 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 [ adapted `guard(pmbus_lock)(data->client)` to manual `pmbus_lock_interruptible()`/`pmbus_unlock()` ] Signed-off-by: Sasha Levin --- drivers/hwmon/pmbus/adm1266.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/hwmon/pmbus/adm1266.c b/drivers/hwmon/pmbus/adm1266.c index a616439cecbf51..e265bfd93dd7c4 100644 --- a/drivers/hwmon/pmbus/adm1266.c +++ b/drivers/hwmon/pmbus/adm1266.c @@ -395,18 +395,25 @@ static int adm1266_nvmem_read(void *priv, unsigned int offset, void *val, size_t if (offset + bytes > data->nvmem_config.size) return -EINVAL; + ret = pmbus_lock_interruptible(data->client); + if (ret) + return ret; + if (offset == 0) { memset(data->dev_mem, 0, data->nvmem_config.size); ret = adm1266_nvmem_read_blackbox(data, data->dev_mem); if (ret) { dev_err(&data->client->dev, "Could not read blackbox!"); + pmbus_unlock(data->client); return ret; } } memcpy(val, data->dev_mem + offset, bytes); + pmbus_unlock(data->client); + return 0; } -- 2.53.0