From: Eli Billauer eli.billauer@gmail.com
[ Upstream commit c002f04c0bc79ec00d4beb75fb631d5bf37419bd ]
@unit_mutex protects @unit from being freed, so obviously it should be released after @unit is used, and not before.
This is a follow-up to commit 282a4b71816b ("char: xillybus: Prevent use-after-free due to race condition") which ensures, among others, the protection of @private_data after @unit_mutex has been released.
Reported-by: Hyunwoo Kim imv4bel@gmail.com Signed-off-by: Eli Billauer eli.billauer@gmail.com Link: https://lore.kernel.org/r/20221117071825.3942-1-eli.billauer@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/char/xillybus/xillybus_class.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/char/xillybus/xillybus_class.c b/drivers/char/xillybus/xillybus_class.c index 0f238648dcfe..e9a288e61c15 100644 --- a/drivers/char/xillybus/xillybus_class.c +++ b/drivers/char/xillybus/xillybus_class.c @@ -227,14 +227,15 @@ int xillybus_find_inode(struct inode *inode, break; }
- mutex_unlock(&unit_mutex); - - if (!unit) + if (!unit) { + mutex_unlock(&unit_mutex); return -ENODEV; + }
*private_data = unit->private_data; *index = minor - unit->lowest_minor;
+ mutex_unlock(&unit_mutex); return 0; } EXPORT_SYMBOL(xillybus_find_inode);