ide: don't call memcpy with the same source and destination

The parisc architecture recently reimplemented the memcpy function and
their reimplementation crashed when source and destination overlapped.

The crash happened in the function ide_complete_cmd where memcpy is called
with the same source and destination pointer. According to the C
specification, memcpy behavior is undefined if the source and destination
range overlaps. This patches fixes the undefined behavior.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c
index 45b3f41a43d4112a7c587c45f25b89b281bfcac3..323af721f8cb96e01393124b85c2342b6e9f8ff8 100644 (file)
--- a/drivers/ide/ide-io.c
+++ b/drivers/ide/ide-io.c
@@ -107,7 +107,7 @@ void ide_complete_cmd(ide_drive_t *drive, struct ide_cmd *cmd, u8 stat, u8 err)
 
                if (cmd->tf_flags & IDE_TFLAG_DYN)
                        kfree(orig_cmd);
-               else
+               else if (cmd != orig_cmd)
                        memcpy(orig_cmd, cmd, sizeof(*cmd));
        }
 }