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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>,
        Matthew Wilcox <willy@infradead.org>,
        "Darrick J . Wong" <djwong@kernel.org>,
        Sasha Levin <sashal@kernel.org>, linux-xfs@vger.kernel.org,
        linux-fsdevel@vger.kernel.org
Subject: [PATCH AUTOSEL 6.4 1/5] iomap: Fix possible overflow condition in iomap_write_delalloc_scan
Date:   Thu,  7 Sep 2023 11:43:45 -0400
Message-Id: <20230907154349.3421707-1-sashal@kernel.org>
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From: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>

[ Upstream commit eee2d2e6ea5550118170dbd5bb1316ceb38455fb ]

folio_next_index() returns an unsigned long value which left shifted
by PAGE_SHIFT could possibly cause an overflow on 32-bit system. Instead
use folio_pos(folio) + folio_size(folio), which does this correctly.

Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/iomap/buffered-io.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 063133ec77f49..5e5bffa384976 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -929,7 +929,7 @@ static int iomap_write_delalloc_scan(struct inode *inode,
 			 * the end of this data range, not the end of the folio.
 			 */
 			*punch_start_byte = min_t(loff_t, end_byte,
-					folio_next_index(folio) << PAGE_SHIFT);
+					folio_pos(folio) + folio_size(folio));
 		}
 
 		/* move offset to start of next folio in range */
-- 
2.40.1