From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	Jad Keskes <inasj268@gmail.com>,
	"Borislav Petkov (AMD)" <bp@alien8.de>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.12 0504/1102] EDAC/device_sysfs: Use kstrtouint() for poll_msec to prevent truncation
Date: Thu, 17 Sep 2026 16:07:27 +0100
Message-ID: <20260917151552.389559356@linuxfoundation.org>
In-Reply-To: <20260917151539.408551884@linuxfoundation.org>
References: <20260917151539.408551884@linuxfoundation.org>
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6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jad Keskes <inasj268@gmail.com>

[ Upstream commit 66cc9dec919dd63d8e4b3d386f7aed3ae684e645 ]

The poll_msec sysfs store file uses simple_strtoul() which accepts an unsigned
long, but the target field (poll_msec) is unsigned int. On 64-bit systems,
a value > UINT_MAX is silently truncated when stored.

Fix the mismatch by using kstrtouint() instead. This rejects values larger
than UINT_MAX at parse time, making truncation impossible. Also add a check
for value < 1 to reject the 0-delay case, which would cause the poll work to
spin without delay and consume 100% CPU.

Fixes: e27e3dac6517 ("drivers/edac: add edac_device class")
Signed-off-by: Jad Keskes <inasj268@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://patch.msgid.link/20260730145549.148229-1-inasj268@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/edac/edac_device_sysfs.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/edac/edac_device_sysfs.c b/drivers/edac/edac_device_sysfs.c
index fcebc4ffea26d..71940f43a0dd8 100644
--- a/drivers/edac/edac_device_sysfs.c
+++ b/drivers/edac/edac_device_sysfs.c
@@ -90,14 +90,21 @@ static ssize_t edac_device_ctl_poll_msec_store(struct edac_device_ctl_info
 					*ctl_info, const char *data,
 					size_t count)
 {
-	unsigned long value;
+	unsigned int value;
+	int ret;
 
 	/* get the value and enforce that it is non-zero, must be at least
 	 * one millisecond for the delay period, between scans
 	 * Then cancel last outstanding delay for the work request
 	 * and set a new one.
 	 */
-	value = simple_strtoul(data, NULL, 0);
+	ret = kstrtouint(data, 0, &value);
+	if (ret < 0)
+		return ret;
+
+	if (value < 1)
+		return -EINVAL;
+
 	edac_device_reset_delay_period(ctl_info, value);
 
 	return count;
-- 
2.53.0