From 508baf1713f32f287bfb4f85d759403ec8ba35a3 Mon Sep 17 00:00:00 2001 From: Linmao Li Date: Mon, 31 Aug 2026 09:45:09 +0800 Subject: [PATCH] hwmon: (corsair-cpro) Create debugfs entries after hwmon registration ccp_debugfs_init() registers debugfs files whose private data is the devm allocated ccp. It runs before hwmon_device_register_with_info(), so when that registration fails, ccp_probe() returns with the files still in place. The HID core then frees ccp, and ccp_remove() is not called for a failed probe, so nothing removes them later either. Reading one of the files dereferences the freed pointer. Create the debugfs entries only after the hwmon device has been registered, so no failing path can leave them behind. The two version queries stay where they are. They send USB commands without holding ccp->mutex, which is only safe as long as nothing else can call send_usb_cmd(); once the hwmon device is registered its callbacks can do so concurrently. Only the debugfs creation moves, and it is told which queries succeeded. Reported-by: Sashiko Closes: https://lore.kernel.org/linux-hwmon/20260708031612.BD7E61F000E9@smtp.kernel.org/ Suggested-by: Guenter Roeck Fixes: 5997eb60f896 ("hwmon: (corsair-cpro) Add firmware and bootloader information") Signed-off-by: Linmao Li Link: https://patch.msgid.link/20260831014509.3352442-1-lilinmao@kylinos.cn Signed-off-by: Guenter Roeck --- drivers/hwmon/corsair-cpro.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/drivers/hwmon/corsair-cpro.c b/drivers/hwmon/corsair-cpro.c index 8354a002f4c5..56de0fe0f544 100644 --- a/drivers/hwmon/corsair-cpro.c +++ b/drivers/hwmon/corsair-cpro.c @@ -566,21 +566,18 @@ static int bootloader_show(struct seq_file *seqf, void *unused) } DEFINE_SHOW_ATTRIBUTE(bootloader); -static void ccp_debugfs_init(struct ccp_device *ccp) +static void ccp_debugfs_init(struct ccp_device *ccp, bool fw_valid, bool bl_valid) { char name[32]; - int ret; scnprintf(name, sizeof(name), "corsaircpro-%s", dev_name(&ccp->hdev->dev)); ccp->debugfs = debugfs_create_dir(name, NULL); - ret = get_fw_version(ccp); - if (!ret) + if (fw_valid) debugfs_create_file("firmware_version", 0444, ccp->debugfs, ccp, &firmware_fops); - ret = get_bl_version(ccp); - if (!ret) + if (bl_valid) debugfs_create_file("bootloader_version", 0444, ccp->debugfs, ccp, &bootloader_fops); } @@ -588,6 +585,7 @@ static void ccp_debugfs_init(struct ccp_device *ccp) static int ccp_probe(struct hid_device *hdev, const struct hid_device_id *id) { struct ccp_device *ccp; + bool fw_valid, bl_valid; int ret; ccp = devm_kzalloc(&hdev->dev, sizeof(*ccp), GFP_KERNEL); @@ -632,7 +630,13 @@ static int ccp_probe(struct hid_device *hdev, const struct hid_device_id *id) if (ret) goto out_hw_close; - ccp_debugfs_init(ccp); + /* + * Query the versions before registering the hwmon device: they send + * USB commands without holding ccp->mutex, which is only safe while + * nothing else can call send_usb_cmd(). + */ + fw_valid = !get_fw_version(ccp); + bl_valid = !get_bl_version(ccp); ccp->hwmon_dev = hwmon_device_register_with_info(&hdev->dev, "corsaircpro", ccp, &ccp_chip_info, NULL); @@ -641,6 +645,8 @@ static int ccp_probe(struct hid_device *hdev, const struct hid_device_id *id) goto out_hw_close; } + ccp_debugfs_init(ccp, fw_valid, bl_valid); + return 0; out_hw_close: