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 F0BCA47D94E; Tue, 16 Jun 2026 16:48:46 +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=1781628528; cv=none; b=n9Nx/mlnOcFIXL9Ji3rxw6Bz1M+SVu4Byf4d4iYLiB7f3hFUzvgK2xsYYXx9FEyUuXzSfH9t1/41nfF3wG33pzYd6JKVzzRHaxxJrBRz+ypG/bagZre1x8lkHgCEtAnZOICAAPWGQgnqS/PglP8kfBiEtWI0coxWB9IrG3TpEh0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781628528; c=relaxed/simple; bh=WvsaMewOPvqh6sgcKmFbVSqaLzKz07P1TX9S2kVewK4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=G+37xiugjkDLYop3C+HFTh8IkEg2ADlncB7tK1DguFdZxKmVPIlY0xILmX6VoXuylGTKaAKKnw8iS3XCUsRqvykKbtBRiqw1OytsDRb0tBeE1DXKzwSV6x51OaBaAnGP1EctB4UoWK692PiKo8eSp9UZMkxyltNDS7xE51qDJYo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=GxNls97d; 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="GxNls97d" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0341F1F000E9; Tue, 16 Jun 2026 16:48:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1781628526; bh=o8nLHBjlmMRUXzuAgVpJ/rkuaCV9JF7CF/LWGzMEDrs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=GxNls97dtHcI82q0dkLHo0NGNf0+ZXgSvQdkyEV3GI0Jcc62QothObztRqLa1jmbE y5F53FRCxkONPET3wim24aMMqlYTM/r5mNGK+nqWqvULeHL2RZ1ZynKsq6oThPxKMP p70NCZ1P6O3GsCzuvVa/kox0uShBe3VldKbNvtRU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Abdurrahman Hussain , Guenter Roeck , Sasha Levin Subject: [PATCH 6.6 080/452] hwmon: (pmbus/adm1266) serialize NVMEM blackbox read with pmbus_lock Date: Tue, 16 Jun 2026 20:25:07 +0530 Message-ID: <20260616145122.086283367@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260616145117.796205997@linuxfoundation.org> References: <20260616145117.796205997@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ 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 518eaf07a123de..432846ef0cf45d 100644 --- a/drivers/hwmon/pmbus/adm1266.c +++ b/drivers/hwmon/pmbus/adm1266.c @@ -421,18 +421,25 @@ 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