From 36f78b0dfa7df4892ba067ccf00d95a4513b4935 Mon Sep 17 00:00:00 2001 From: "Christophe Leroy (CS GROUP)" Date: Thu, 9 Jul 2026 13:40:06 +0200 Subject: [PATCH] bitmap: Properly initialise destination bitmap for scatter & gather test Erhard reports failure of bitmap tests on powerpc: test_bitmap: loaded. test_bitmap: [lib/test_bitmap.c:397] bitmaps contents differ: expected "1,3-4,9", got "1,3-4,9,65-71,73-79,81-87,89-95,97-99" test_bitmap: parselist('0-2047:128/256'): 912 test_bitmap: scnprintf("%*pbl", '0-32767'): 5977 test_bitmap: test_bitmap_read_perf: 1191082 test_bitmap: test_bitmap_write_perf: 1270153 test_bitmap: failed 1 out of 208655 tests It happens mainly when CONFIG_INIT_STACK_ALL_PATTERN is set. Commit 6b5a4b687367 ("bitmap: Add test for out-of-boundary modifications for scatter & gather") extended the test to out-of-boundary bits, but those bits were left uninitialised. Properly initialise the entire result bitmap before the test. [Yury: minor commit message tweaks] Reported-by: Erhard Furtner Closes: https://lore.kernel.org/all/ca3547ae-8b79-43a2-a758-23ec980bfd9a@mailbox.org Fixes: 6b5a4b687367 ("bitmap: Add test for out-of-boundary modifications for scatter & gather") Signed-off-by: Christophe Leroy (CS GROUP) Reviewed-by: Andy Shevchenko Signed-off-by: Yury Norov --- lib/test_bitmap.c | 1 + 1 file changed, 1 insertion(+) diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c index 8665df77c960..56bd23059b26 100644 --- a/lib/test_bitmap.c +++ b/lib/test_bitmap.c @@ -429,6 +429,7 @@ static void __init test_bitmap_sg(void) /* Scatter/gather relationship */ bitmap_zero(bmap_tmp, 100); + bitmap_zero(bmap_res, 100); bitmap_gather(bmap_tmp, bmap_scatter, sg_mask, nbits); bitmap_scatter(bmap_res, bmap_tmp, sg_mask, nbits); expect_eq_bitmap(bmap_scatter, bmap_res, 100);