From: Haoxiang Li <haoxiang_li2024@163.com>
Date: Tue, 18 Feb 2025 03:41:04 +0000 (+0800)
Subject: s390/tty: Fix a potential memory leak bug
X-Git-Tag: v6.15-rc1~113^2~35
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ad9bb8f049717d64c5e62b2a44954be9f681c65b;p=thirdparty%2Fkernel%2Flinux.git

s390/tty: Fix a potential memory leak bug

The check for get_zeroed_page() leads to a direct return
and overlooked the memory leak caused by loop allocation.
Add a free helper to free spaces allocated by get_zeroed_page().

Signed-off-by: Haoxiang Li <haoxiang_li2024@163.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20250218034104.2436469-1-haoxiang_li2024@163.com
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
---

diff --git a/drivers/s390/char/sclp_tty.c b/drivers/s390/char/sclp_tty.c
index acd5ea0f7381c..0a92d08830e7c 100644
--- a/drivers/s390/char/sclp_tty.c
+++ b/drivers/s390/char/sclp_tty.c
@@ -490,6 +490,17 @@ static const struct tty_operations sclp_ops = {
 	.flush_buffer = sclp_tty_flush_buffer,
 };
 
+/* Release allocated pages. */
+static void __init __sclp_tty_free_pages(void)
+{
+	struct list_head *page, *p;
+
+	list_for_each_safe(page, p, &sclp_tty_pages) {
+		list_del(page);
+		free_page((unsigned long)page);
+	}
+}
+
 static int __init
 sclp_tty_init(void)
 {
@@ -516,6 +527,7 @@ sclp_tty_init(void)
 	for (i = 0; i < MAX_KMEM_PAGES; i++) {
 		page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
 		if (page == NULL) {
+			__sclp_tty_free_pages();
 			tty_driver_kref_put(driver);
 			return -ENOMEM;
 		}