[PATCH v2] crypto: ccp: Initialize DBC ioctl mutex before registering device

[Runyu Xiao]

dbc_dev_init() registers the DBC misc device before initializing
ioctl_mutex. Once misc_register() publishes the device, userspace can
open it and invoke dbc_ioctl() while the mutex is still uninitialized.

Initialize ioctl_mutex before calling misc_register() so the published
ioctl callback always sees an initialized mutex.

Fixes: c04cf9e14f10 ("crypto: ccp - Add support for fetching a nonce for dynamic boost control")
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/all/20260829133410.1708684-1-runyu.xiao@xxxxxxxxxx/
Signed-off-by: Runyu Xiao <runyu.xiao@xxxxxxxxxx>
Assisted-by: Codex:GPT-5
---
v2:
- Move mutex initialization before setting up the misc device, as suggested
  by Tom Lendacky.

 drivers/crypto/ccp/dbc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/crypto/ccp/dbc.c b/drivers/crypto/ccp/dbc.c
index 410084a9039c..4db49a14550c 100644
--- a/drivers/crypto/ccp/dbc.c
+++ b/drivers/crypto/ccp/dbc.c
@@ -235,6 +235,8 @@ int dbc_dev_init(struct psp_device *psp)
 		goto cleanup_mbox;
 	}
 
+	mutex_init(&dbc_dev->ioctl_mutex);
+
 	dbc_dev->char_dev.minor = MISC_DYNAMIC_MINOR;
 	dbc_dev->char_dev.name = "dbc";
 	dbc_dev->char_dev.fops = &dbc_fops;
@@ -243,8 +245,6 @@ int dbc_dev_init(struct psp_device *psp)
 	if (ret)
 		goto cleanup_mbox;
 
-	mutex_init(&dbc_dev->ioctl_mutex);
-
 	return 0;
 
 cleanup_mbox: