[PATCH AUTOSEL 5.4 1/2] printk: Fix signed integer overflow when defining LOG_BUF_LEN_MAX

[PATCH AUTOSEL 5.4 1/2] printk: Fix signed integer overflow when defining LOG_BUF_LEN_MAX

[Sasha Levin]

From: Kuan-Wei Chiu <visitorckw@gmail.com>

[ Upstream commit 3d6f83df8ff2d5de84b50377e4f0d45e25311c7a ]

Shifting 1 << 31 on a 32-bit int causes signed integer overflow, which
leads to undefined behavior. To prevent this, cast 1 to u32 before
performing the shift, ensuring well-defined behavior.

This change explicitly avoids any potential overflow by ensuring that
the shift occurs on an unsigned 32-bit integer.

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Acked-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20240928113608.1438087-1-visitorckw@gmail.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/printk/printk.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index ae1a97dd0c3cb..f6e1e154d9c18 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -457,7 +457,7 @@ static u32 clear_idx;
 /* record buffer */
 #define LOG_ALIGN __alignof__(struct printk_log)
 #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT)
-#define LOG_BUF_LEN_MAX (u32)(1 << 31)
+#define LOG_BUF_LEN_MAX ((u32)1 << 31)
 static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN);
 static char *log_buf = __log_buf;
 static u32 log_buf_len = __LOG_BUF_LEN;
-- 
2.39.5

[PATCH AUTOSEL 5.4 2/2] drm/sti: hdmi: use eld_mutex to protect access to connector->eld

[Sasha Levin]

From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

[ Upstream commit e99c0b517bcd53cf61f998a3c4291333401cb391 ]

Reading access to connector->eld can happen at the same time the
drm_edid_to_eld() updates the data. Take the newly added eld_mutex in
order to protect connector->eld from concurrent access.

Reviewed-by: Maxime Ripard <mripard@kernel.org>
Acked-by: Raphael Gallais-Pou <rgallaispou@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241206-drm-connector-eld-mutex-v2-9-c9bce1ee8bea@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/sti/sti_hdmi.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/sti/sti_hdmi.c b/drivers/gpu/drm/sti/sti_hdmi.c
index c5547fedebe30..ce7cc84499f45 100644
--- a/drivers/gpu/drm/sti/sti_hdmi.c
+++ b/drivers/gpu/drm/sti/sti_hdmi.c
@@ -1214,7 +1214,9 @@ static int hdmi_audio_get_eld(struct device *dev, void *data, uint8_t *buf, size
 	struct drm_connector *connector = hdmi->drm_connector;
 
 	DRM_DEBUG_DRIVER("\n");
+	mutex_lock(&connector->eld_mutex);
 	memcpy(buf, connector->eld, min(sizeof(connector->eld), len));
+	mutex_unlock(&connector->eld_mutex);
 
 	return 0;
 }
-- 
2.39.5