filemap: avoid truncating 64-bit offset to 32 bits

BugLink: https://bugs.launchpad.net/bugs/2107449

commit f505e6c91e7a22d10316665a86d79f84d9f0ba76 upstream.

On 32-bit kernels, folio_seek_hole_data() was inadvertently truncating a
64-bit value to 32 bits, leading to a possible infinite loop when writing
to an xfs filesystem.

Link: https://lkml.kernel.org/r/20250102190540.1356838-1-marco.nelissen@gmail.com
Fixes: 54fa39a ("iomap: use mapping_seek_hole_data")
Signed-off-by: Marco Nelissen <marco.nelissen@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CVE-2025-21665
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

Author: marcone

mm/filemap.c

@@ -2983,7 +2983,7 @@ static inline loff_t folio_seek_hole_data(struct xa_state *xas,
 		if (ops->is_partially_uptodate(folio, offset, bsz) ==
 							seek_data)
 			break;
-		start = (start + bsz) & ~(bsz - 1);
+		start = (start + bsz) & ~((u64)bsz - 1);
 		offset += bsz;
 	} while (offset < folio_size(folio));
 unlock: