From: Sasha Levin <sashal@kernel.org>
To: stable@vger.kernel.org
Cc: Fan Wu <fanwu01@zju.edu.cn>,
	Ulf Hansson <ulfh@kernel.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10.y 4/4] mmc: hsq: Fix use-after-free in retry work
Date: Tue, 22 Sep 2026 14:16:47 -0400
Message-ID: <20260922181647.3522363-4-sashal@kernel.org>
In-Reply-To: <20260922181647.3522363-1-sashal@kernel.org>
References: <2026092257-ranger-harmonize-17aa@gregkh>
 <20260922181647.3522363-1-sashal@kernel.org>
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From: Fan Wu <fanwu01@zju.edu.cn>

[ Upstream commit 5d132990475f02cfa1debe03d50b479432864ebd ]

mmc_hsq_pump_requests() queues retry_work when request_atomic() returns
-EBUSY; today sdhci-sprd is the only consumer that implements
request_atomic(). The work is embedded in a devm-allocated mmc_hsq, but
is never cancelled during driver removal. Work still pending at unbind
can therefore run after the devm allocation has been released and
dereference hsq->mmc and hsq->mrq.

Use devm_work_autocancel() to cancel and drain retry_work before the devm
allocation is released. By the time devres cleanup begins,
mmc_remove_host() has already stopped the host, so no new requests can
arm the work.

This issue was found by an in-house static analysis tool.

Fixes: 6db96e5810e0 ("mmc: host: Introduce the request_atomic() for the host")
Cc: stable@vger.kernel.org
Assisted-by: Codex:gpt-5.6
Signed-off-by: Fan Wu <fanwu01@zju.edu.cn>
Signed-off-by: Ulf Hansson <ulfh@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/mmc/host/mmc_hsq.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/mmc_hsq.c b/drivers/mmc/host/mmc_hsq.c
index 424dc7b07858f..473aa02973d65 100644
--- a/drivers/mmc/host/mmc_hsq.c
+++ b/drivers/mmc/host/mmc_hsq.c
@@ -7,6 +7,7 @@
  * Author: Baolin Wang <baolin.wang@linaro.org>
  */
 
+#include <linux/devm-helpers.h>
 #include <linux/mmc/card.h>
 #include <linux/mmc/host.h>
 #include <linux/module.h>
@@ -324,6 +325,7 @@ static const struct mmc_cqe_ops mmc_hsq_ops = {
 
 int mmc_hsq_init(struct mmc_hsq *hsq, struct mmc_host *mmc)
 {
+	int ret;
 	int i;
 	hsq->num_slots = HSQ_NUM_SLOTS;
 	hsq->next_tag = HSQ_INVALID_TAG;
@@ -341,7 +343,11 @@ int mmc_hsq_init(struct mmc_hsq *hsq, struct mmc_host *mmc)
 	for (i = 0; i < HSQ_NUM_SLOTS; i++)
 		hsq->tag_slot[i] = HSQ_INVALID_TAG;
 
-	INIT_WORK(&hsq->retry_work, mmc_hsq_retry_handler);
+	ret = devm_work_autocancel(mmc_dev(mmc), &hsq->retry_work,
+				   mmc_hsq_retry_handler);
+	if (ret)
+		return ret;
+
 	spin_lock_init(&hsq->lock);
 	init_waitqueue_head(&hsq->wait_queue);
 
-- 
2.53.0