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 265EC331A63 for ; Tue, 2 Jun 2026 02:06:03 +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=1780365965; cv=none; b=GtQewuC/X9UWmniYzhEXqCczQhgZ3S8VJYPCBdbmHYWseikTwF1+GzoqfMTYmWwB43G6MUVBJ66mF3r6A1E9strxA5nTYecyDEqQ2qf9Yy+fdXBndQINOnl6L80QYdURgF+4flS7uYFcQ6JP2b+/2xx8KfiNysa8gsW8EZ9gOqo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780365965; c=relaxed/simple; bh=00wtayZ38e0ENXaG9j/6LOUZbH5ElYvP+yD7kaFHiFI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RDOyBz4uGG2lAgYWmU6IMFTYiux94Mdnycqlo9SJYwOjmC30PpkRe83mbzn/c4CIrndO6GVtd0YETkIy1M7jUg6PQ5a4lVj3IGg/xxJnqX1wKubBxvDi4wOX5Vi5TFwHFlOgKu1Djkjb8hSlAiJuHvD2Ddttg1t15M6xDCvF8jk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HriTIFsr; 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="HriTIFsr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 434081F00893; Tue, 2 Jun 2026 02:06:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780365963; bh=KFwD2uPwhP3OvTobxGg/hMi6cglDhWVkHvlZ7TrKCy8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=HriTIFsrtoKJyo4aIdtPIOhecDX7G1hqUye9pkHsloHyFVdmSs7Y8Oqasxd054s26 jrqyJGdP4xtXmycd++QNJK7xdl6+0wiDOov99JErR+ulkjTsLS/MPgRplu1mt7i3SL G9OMBZieUKMuE86ueZjQEkF2Xpc9yRl61JGdhORARlDo451mwBk4Nr/xuNX+enIymg Ud2I9g9OOsu0DNS7Zl0j+vXOJj4JLvof4f9021Wo6GsSKdLYgsUmPviyYwYdTeV86v QMMQlq5JJytgymLNebEhEanpmO6sQ0mXodrTGBEz92VF3s1cWpblXxh1QEDrJ/wwSS SsNlqFkkvulvQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Abdurrahman Hussain , Guenter Roeck , Sasha Levin Subject: [PATCH 6.6.y] hwmon: (pmbus/adm1266) serialize NVMEM blackbox read with pmbus_lock Date: Mon, 1 Jun 2026 22:06:01 -0400 Message-ID: <20260602020601.609941-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026052846-kinswoman-crushing-8acf@gregkh> References: <2026052846-kinswoman-crushing-8acf@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 a8690d6c9b9cb0..f5b55159e83b07 100644 --- a/drivers/hwmon/pmbus/adm1266.c +++ b/drivers/hwmon/pmbus/adm1266.c @@ -393,18 +393,25 @@ 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