linux-kernel - Re: [PATCH v12 07/22] selftests/vm: fixed bugs in pkey_disable

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Date:   Wed, 28 Mar 2018 17:47:04 -0300
From:   Thiago Jung Bauermann <bauerman@...ux.vnet.ibm.com>
To:     Dave Hansen <dave.hansen@...el.com>
Cc:     Ram Pai <linuxram@...ibm.com>, shuahkh@....samsung.com,
        linux-kselftest@...r.kernel.org, mpe@...erman.id.au,
        linuxppc-dev@...ts.ozlabs.org, linux-mm@...ck.org, x86@...nel.org,
        linux-arch@...r.kernel.org, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org, mingo@...hat.com,
        akpm@...ux-foundation.org, benh@...nel.crashing.org,
        paulus@...ba.org, khandual@...ux.vnet.ibm.com,
        aneesh.kumar@...ux.vnet.ibm.com, bsingharora@...il.com,
        hbabu@...ibm.com, mhocko@...nel.org, ebiederm@...ssion.com,
        arnd@...db.de
Subject: Re: [PATCH v12 07/22] selftests/vm: fixed bugs in pkey_disable_clear()


Dave Hansen <dave.hansen@...el.com> writes:

> On 02/21/2018 05:55 PM, Ram Pai wrote:
>> --- a/tools/testing/selftests/vm/protection_keys.c
>> +++ b/tools/testing/selftests/vm/protection_keys.c
>> @@ -461,7 +461,7 @@ void pkey_disable_clear(int pkey, int flags)
>>  			pkey, pkey, pkey_rights);
>>  	pkey_assert(pkey_rights >= 0);
>>
>> -	pkey_rights |= flags;
>> +	pkey_rights &= ~flags;
>>
>>  	ret = pkey_set(pkey, pkey_rights, 0);
>>  	/* pkey_reg and flags have the same format */
>> @@ -475,7 +475,7 @@ void pkey_disable_clear(int pkey, int flags)
>>  	dprintf1("%s(%d) pkey_reg: 0x%016lx\n", __func__,
>>  			pkey, rdpkey_reg());
>>  	if (flags)
>> -		assert(rdpkey_reg() > orig_pkey_reg);
>> +		assert(rdpkey_reg() < orig_pkey_reg);
>>  }
>>
>>  void pkey_write_allow(int pkey)
>
> This seems so horribly wrong that I wonder how it worked in the first
> place.  Any idea?

The code simply wasn't used. pkey_disable_clear() is called by
pkey_write_allow() and pkey_access_allow(), but before this patch series
nothing called either of these functions.


--
Thiago Jung Bauermann
IBM Linux Technology Center