linux-kernel - Re: [PATCH 3/5] lib/bitmap: add test for bitmap_{from,to}

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Y/qhL8kSzzhMm+tO@yury-laptop>
Date:   Sat, 25 Feb 2023 16:04:59 -0800
From:   Yury Norov <yury.norov@...il.com>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     linux-kernel@...r.kernel.org,
        Alexander Gordeev <agordeev@...ux.ibm.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Christian Borntraeger <borntraeger@...ux.ibm.com>,
        Claudio Imbrenda <imbrenda@...ux.ibm.com>,
        David Hildenbrand <david@...hat.com>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Janosch Frank <frankja@...ux.ibm.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Sven Schnelle <svens@...ux.ibm.com>,
        Vasily Gorbik <gor@...ux.ibm.com>, linux-s390@...r.kernel.org,
        kvm@...r.kernel.org
Subject: Re: [PATCH 3/5] lib/bitmap: add test for bitmap_{from,to}_arr64

On Sat, Feb 25, 2023 at 10:47:02AM -0800, Guenter Roeck wrote:
> Hi,
> 
> On Thu, Apr 28, 2022 at 01:51:14PM -0700, Yury Norov wrote:
> > Test newly added bitmap_{from,to}_arr64() functions similarly to
> > already existing bitmap_{from,to}_arr32() tests.
> > 
> > Signed-off-by: Yury Norov <yury.norov@...il.com>
> 
> Ever since this test is in the tree, several of my boot tests show
> lots of messages such as
> 
> test_bitmap: bitmap_to_arr64(nbits == 1): tail is not safely cleared: 0xa5a5a5a500000001 (must be 0x0000000000000001)
> test_bitmap: bitmap_to_arr64(nbits == 2): tail is not safely cleared: 0xa5a5a5a500000001 (must be 0x0000000000000003)
> test_bitmap: bitmap_to_arr64(nbits == 3): tail is not safely cleared: 0xa5a5a5a500000001 (must be 0x0000000000000007)
> ...
> test_bitmap: bitmap_to_arr64(nbits == 927): tail is not safely cleared: 0xa5a5a5a500000000 (must be 0x000000007fffffff)
> test_bitmap: bitmap_to_arr64(nbits == 928): tail is not safely cleared: 0xa5a5a5a580000000 (must be 0x00000000ffffffff)

This may be a real problem. Can you share what's the system is? What's
endianness and register length?

+ Alexander Lobakin, the author of the exact subtest.
 
> but then:
> 
> test_bitmap: all 6550 tests passed

It's because corresponding error path doesn't increment failed_tests
counter. I'll send a fix shortly.

> 
> The message suggests an error, given that it is displayed with pr_err,
> but the summary suggests otherwise.
> 
> Is the message just noise, or is there a problem ?
> 
> Thanks,
> Guenter
> 
> > ---
> >  lib/test_bitmap.c | 25 +++++++++++++++++++++++++
> >  1 file changed, 25 insertions(+)
> > 
> > diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
> > index 0c82f07f74fc..d5923a640457 100644
> > --- a/lib/test_bitmap.c
> > +++ b/lib/test_bitmap.c
> > @@ -585,6 +585,30 @@ static void __init test_bitmap_arr32(void)
> >  	}
> >  }
> >  
> > +static void __init test_bitmap_arr64(void)
> > +{
> > +	unsigned int nbits, next_bit;
> > +	u64 arr[EXP1_IN_BITS / 64];
> > +	DECLARE_BITMAP(bmap2, EXP1_IN_BITS);
> > +
> > +	memset(arr, 0xa5, sizeof(arr));
> > +
> > +	for (nbits = 0; nbits < EXP1_IN_BITS; ++nbits) {
> > +		memset(bmap2, 0xff, sizeof(arr));
> > +		bitmap_to_arr64(arr, exp1, nbits);
> > +		bitmap_from_arr64(bmap2, arr, nbits);
> > +		expect_eq_bitmap(bmap2, exp1, nbits);
> > +
> > +		next_bit = find_next_bit(bmap2, round_up(nbits, BITS_PER_LONG), nbits);
> > +		if (next_bit < round_up(nbits, BITS_PER_LONG))
> > +			pr_err("bitmap_copy_arr64(nbits == %d:"
> > +				" tail is not safely cleared: %d\n", nbits, next_bit);
> > +
> > +		if (nbits < EXP1_IN_BITS - 64)
> > +			expect_eq_uint(arr[DIV_ROUND_UP(nbits, 64)], 0xa5a5a5a5);
> > +	}
> > +}
> > +
> >  static void noinline __init test_mem_optimisations(void)
> >  {
> >  	DECLARE_BITMAP(bmap1, 1024);
> > @@ -852,6 +876,7 @@ static void __init selftest(void)
> >  	test_copy();
> >  	test_replace();
> >  	test_bitmap_arr32();
> > +	test_bitmap_arr64();
> >  	test_bitmap_parse();
> >  	test_bitmap_parselist();
> >  	test_bitmap_printlist();
> > -- 
> > 2.32.0
> >