[PATCH AUTOSEL 5.15 7/8] s390/tty: Fix a potential memory leak bug

Sasha Levin
2025-04-04T00:07:47Z

From: Haoxiang Li <haoxiang_li2024@163.com>

[ Upstream commit ad9bb8f049717d64c5e62b2a44954be9f681c65b ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/s390/char/sclp_tty.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/drivers/s390/char/sclp_tty.c b/drivers/s390/char/sclp_tty.c
index 971fbb52740bf..432dad2a22664 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;
}
--
2.39.5