[PATCH 5.2 269/313] lib/lzo/lzo1x_compress.c: fix alignment bug in lzo-rle

[Greg Kroah-Hartman]

From: Dave Rodgman <dave.rodgman@xxxxxxx>

commit 09b35b4192f6682dff96a093ab1930998cdb73b4 upstream.

Fix an unaligned access which breaks on platforms where this is not
permitted (e.g., Sparc).

Link: http://lkml.kernel.org/r/20190912145502.35229-1-dave.rodgman@xxxxxxx
Signed-off-by: Dave Rodgman <dave.rodgman@xxxxxxx>
Cc: Dave Rodgman <dave.rodgman@xxxxxxx>
Cc: Markus F.X.J. Oberhumer <markus@xxxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 lib/lzo/lzo1x_compress.c |   14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

--- a/lib/lzo/lzo1x_compress.c
+++ b/lib/lzo/lzo1x_compress.c
@@ -83,17 +83,19 @@ next:
 					ALIGN((uintptr_t)ir, 4)) &&
 					(ir < limit) && (*ir == 0))
 				ir++;
-			for (; (ir + 4) <= limit; ir += 4) {
-				dv = *((u32 *)ir);
-				if (dv) {
+			if (IS_ALIGNED((uintptr_t)ir, 4)) {
+				for (; (ir + 4) <= limit; ir += 4) {
+					dv = *((u32 *)ir);
+					if (dv) {
 #  if defined(__LITTLE_ENDIAN)
-					ir += __builtin_ctz(dv) >> 3;
+						ir += __builtin_ctz(dv) >> 3;
 #  elif defined(__BIG_ENDIAN)
-					ir += __builtin_clz(dv) >> 3;
+						ir += __builtin_clz(dv) >> 3;
 #  else
 #    error "missing endian definition"
 #  endif
-					break;
+						break;
+					}
 				}
 			}
 #endif