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authorEli Billauer <eli.billauer@gmail.com>2022-11-17 10:18:25 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2022-11-23 21:44:04 +0300
commitc002f04c0bc79ec00d4beb75fb631d5bf37419bd (patch)
tree3ca57977121e09f82a4124ee4ddabed96dd2e008
parent0ef77698b85603d21453daf32ae70f76ae62ccae (diff)
downloadlinux-c002f04c0bc79ec00d4beb75fb631d5bf37419bd.tar.xz
char: xillybus: Fix trivial bug with mutex
@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>
-rw-r--r--drivers/char/xillybus/xillybus_class.c7
1 files 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);