[PATCH 4.19 042/273] reiserfs: Check the return value from __getblk()

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4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Matthew Wilcox <willy@xxxxxxxxxxxxx>

[ 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@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/lkml/CAFcO6XOacq3hscbXevPQP7sXRoYFz34ZdKPYjmd6k5sZuhGFDw@xxxxxxxxxxxxxx/
Tested-by: butt3rflyh4ck <butterflyhuangxx@xxxxxxxxx>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") # probably introduced in 2002
Acked-by: Edward Shishkin <edward.shishkin@xxxxxxxxx>
Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 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 78be6dbcd7627..3425a04bc8a01 100644
--- a/fs/reiserfs/journal.c
+++ b/fs/reiserfs/journal.c
@@ -2336,7 +2336,7 @@ 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) {
@@ -2346,6 +2346,8 @@ 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






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