Commit v9.8-95-g4c0cf3864 intended to initialize
ext_start to src_pos, as was described at:
https://lists.gnu.org/r/coreutils/2025-11/msg00035.html
However ipos was inadvertently used, which is only
valid the first time through the loop.

* src/copy-file-data.c (lseek_copy): Use scan_inference->hole_start
only with the initial offset passed to lseek_copy().
* NEWS: Mention the bug fix.
Reported at https://github.com/coreutils/coreutils/issues/159
---
 NEWS                 | 5 +++++
 src/copy-file-data.c | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/NEWS b/NEWS
index e3858a855..af8667aeb 100644
--- a/NEWS
+++ b/NEWS
@@ -4,6 +4,11 @@ GNU coreutils NEWS                                    -*- 
outline -*-
 
 ** Bug fixes
 
+  'cp' no longer enters an infinite loop copying sparse files with SEEK_HOLE.
+  E.g., this was seen copying files with certain extent patterns,
+  from ext4 to another file system.
+  [bug introduced in coreutils-9.9]
+
   'date' no longer fails with format directives that return an empty string.
   [bug introduced in coreutils-9.9]
 
diff --git a/src/copy-file-data.c b/src/copy-file-data.c
index 927a6e048..56b669fe7 100644
--- a/src/copy-file-data.c
+++ b/src/copy-file-data.c
@@ -338,7 +338,7 @@ lseek_copy (int src_fd, int dest_fd, char **abuf, idx_t 
buf_size,
   for (off_t ext_start = scan_inference->ext_start;
        0 <= ext_start && ext_start < max_ipos; )
     {
-      off_t ext_end = (ext_start == ipos
+      off_t ext_end = (ext_start == src_pos
                        ? scan_inference->hole_start
                        : lseek (src_fd, ext_start, SEEK_HOLE));
       if (0 <= ext_end)
-- 
2.52.0


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