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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Cristian Marussi <cristian.marussi@arm.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Sudeep Holla <sudeep.holla@arm.com>,
        Sasha Levin <sashal@kernel.org>,
        linux-arm-kernel@lists.infradead.org
Subject: [PATCH AUTOSEL 4.19 09/11] firmware: arm_scmi: Fix range check for the maximum number of pending messages
Date:   Thu, 22 Jul 2021 23:58:33 -0400
Message-Id: <20210723035835.532148-9-sashal@kernel.org>
In-Reply-To: <20210723035835.532148-1-sashal@kernel.org>
References: <20210723035835.532148-1-sashal@kernel.org>
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From: Cristian Marussi <cristian.marussi@arm.com>

[ Upstream commit bdb8742dc6f7c599c3d61959234fe4c23638727b ]

SCMI message headers carry a sequence number and such field is sized to
allow for MSG_TOKEN_MAX distinct numbers; moreover zero is not really an
acceptable maximum number of pending in-flight messages.

Fix accordingly the checks performed on the value exported by transports
in scmi_desc.max_msg

Link: https://lore.kernel.org/r/20210712141833.6628-3-cristian.marussi@arm.com
Reported-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
[sudeep.holla: updated the patch title and error message]
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/firmware/arm_scmi/driver.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 081fbe28da4b..af5139eb96b5 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -629,8 +629,9 @@ static int scmi_xfer_info_init(struct scmi_info *sinfo)
 	struct scmi_xfers_info *info = &sinfo->minfo;
 
 	/* Pre-allocated messages, no more than what hdr.seq can support */
-	if (WARN_ON(desc->max_msg >= MSG_TOKEN_MAX)) {
-		dev_err(dev, "Maximum message of %d exceeds supported %ld\n",
+	if (WARN_ON(!desc->max_msg || desc->max_msg > MSG_TOKEN_MAX)) {
+		dev_err(dev,
+			"Invalid maximum messages %d, not in range [1 - %lu]\n",
 			desc->max_msg, MSG_TOKEN_MAX);
 		return -EINVAL;
 	}
-- 
2.30.2