[PATCH 5.10 065/406] reiserfs: Check the return value from __getblk()

Greg Kroah-Hartman
2023-09-17T19:22:02Z

From: Matthew Wilcox <willy@infradead.org>

[ Upstream commit ba38980add7ffc9e674ada5b4ded4e7d14e76581 ]

__getblk() can return a NULL pointer if we run out of memory or if we
try to access beyond the end of the device; check it and handle it
appropriately.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/lkml/CAFcO6XOacq3hscbXevPQP7sXRoYFz34ZdKPYjmd6k5sZuhGFDw@mail.gmail.com/
Tested-by: butt3rflyh4ck <butterflyhuangxx@gmail.com>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") # probably introduced in 2002
Acked-by: Edward Shishkin <edward.shishkin@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/reiserfs/journal.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c
index df5fc12a6ceed..cfa4defbd0401 100644
--- a/fs/reiserfs/journal.c
+++ b/fs/reiserfs/journal.c
@@ -2325,7 +2325,7 @@ static struct buffer_head *reiserfs_breada(struct block_device *dev,
int i, j;

bh = __getblk(dev, block, bufsize);
- if (buffer_uptodate(bh))
+ if (!bh || buffer_uptodate(bh))
return (bh);

if (block + BUFNR > max_block) {
@@ -2335,6 +2335,8 @@ static struct buffer_head *reiserfs_breada(struct block_device *dev,
j = 1;
for (i = 1; i < blocks; i++) {
bh = __getblk(dev, block + i, bufsize);
+ if (!bh)
+ break;
if (buffer_uptodate(bh)) {
brelse(bh);
break;
--
2.40.1