Re: test_bitmap fails on ppc/ppc64 on kernels v7.1.3, v7.2-rc2
From: Erhard Furtner <hidden>
Date: 2026-07-07 23:25:27
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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 testsOn QEMU (pmac32_defconfig) I get: test_bitmap: loaded. test_bitmap: parselist('0-2047:128/256'): 2200 test_bitmap: scnprintf("%*pbl", '0-32767'): 26440 test_bitmap: test_bitmap_read_perf: 1819760 test_bitmap: test_bitmap_write_perf: 18189840 test_bitmap: all 208655 tests passed On QEMU with your confirm I get: [ 1.162486] test_bitmap: loaded. [ 1.177069] 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" [ 1.180599] test_bitmap: parselist('0-2047:128/256'): 2920 [ 1.190105] test_bitmap: scnprintf("%*pbl", '0-32767'): 65560 [ 1.427378] test_bitmap: test_bitmap_read_perf: 9546321 [ 1.438769] test_bitmap: test_bitmap_write_perf: 9344481 [ 1.457679] test_bitmap: failed 1 out of 208655 tests So there is something with your config
Interesting! As I get the same test failure on my Talos II too.
Anyhow, I was able to bisect the issue. Offending commit is:
# git bisect bad
6b5a4b68736798df1031404a2fad06d031253ef7 is the first bad commit
commit 6b5a4b68736798df1031404a2fad06d031253ef7 (HEAD)
Author: Andy Shevchenko [off-list ref]
Date: Thu Feb 26 12:16:44 2026 +0100
bitmap: Add test for out-of-boundary modifications for scatter & gather
Make sure that bitmap_scatter() and bitmap_gather() do not modify
the bits outside of the given nbits span.
Signed-off-by: Andy Shevchenko [off-list ref]
Signed-off-by: Yury Norov [off-list ref]
lib/test_bitmap.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
Reverting this commit on top of v7.2-rc2 lets the test pass:
test_bitmap: loaded.
test_bitmap: parselist('0-2047:128/256'): 888
test_bitmap: scnprintf("%*pbl", '0-32767'): 6074
test_bitmap: test_bitmap_read_perf: 1190938
test_bitmap: test_bitmap_write_perf: 1259471
test_bitmap: all 208655 tests passed
Your hint about my config made me check a few options and I found the
offending one, which is INIT_STACK_ALL_PATTERN=y. On a kernel built with
INIT_STACK_ALL_ZERO=y the issue does not show up.
Regards,
Erhard