Re: test_bitmap fails on ppc/ppc64 on kernels v7.1.3, v7.2-rc2

["Christophe Leroy (CS GROUP)" <chleroy@kernel.org>]

Hi,

Le 06/07/2026 à 21:27, Erhard Furtner a écrit :
> Greetings!
> 
> I don't get this on my x86_64 machines, but on ppc32 (PowerMac G4 DP) 
> and on ppc64 (Talos II, POWER9) running Gentoo Linux. This dmesg snippet 
> is from the G4:
> 
> Total memory = 2048MB; using 4096kB for hash table
> Activating Kernel Userspace Access Protection
> Activating Kernel Userspace Execution Prevention
> Linux version 7.2.0-rc2-PMacG4 (root@T1000) (gcc (Gentoo 15.3.0 p8) 
> 15.3.0, GNU ld (Gentoo 2.46.0 p1) 2.46.0) #1 SMP PREEMPT Mon Jul  6 
> 20:22:47 CEST 2026
> 
> [...]
> 
> 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

On 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

> 
> 
> Full dmesg available at request. Kernel .config attached.
> 
> Regards,
> Erhard