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Message-ID: <d0fb08ca-872e-1b46-9c6c-4896fdaebb0a@igalia.com>
Date:   Thu, 6 Oct 2022 20:35:27 -0300
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Subject: Re: [PATCH 1/8] pstore: Improve error reporting in case of backend
 overlap
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To:     Kees Cook <keescook@chromium.org>
Cc:     linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        kernel-dev@igalia.com, kernel@gpiccoli.net, anton@enomsg.org,
        ccross@android.com, tony.luck@intel.com
References: <20221006224212.569555-1-gpiccoli@igalia.com>
 <20221006224212.569555-2-gpiccoli@igalia.com>
 <202210061627.E29FCDBE1@keescook>
From:   "Guilherme G. Piccoli" <gpiccoli@igalia.com>
In-Reply-To: <202210061627.E29FCDBE1@keescook>
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On 06/10/2022 20:27, Kees Cook wrote:
> On Thu, Oct 06, 2022 at 07:42:05PM -0300, Guilherme G. Piccoli wrote:
>> The pstore infrastructure supports one single backend at a time;
>> trying to load a another backend causes an error and displays a
>> message, introduced on commit 0d7cd09a3dbb ("pstore: Improve
>> register_pstore() error reporting").
>>
>> Happens that this message is not really clear about the situation,
>> also the current error returned (-EPERM) isn't accurate, whereas
>> -EBUSY makes more sense. We have another place in the code that
>> relies in the -EBUSY return for a similar check.
>>
>> So, make it consistent here by returning -EBUSY and using a
>> similar message in both scenarios.
>>
>> Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
>> ---
>>  fs/pstore/platform.c | 5 +++--
>>  1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
>> index 0c034ea39954..c32957e4b256 100644
>> --- a/fs/pstore/platform.c
>> +++ b/fs/pstore/platform.c
>> @@ -562,8 +562,9 @@ static int pstore_write_user_compat(struct pstore_record *record,
>>  int pstore_register(struct pstore_info *psi)
>>  {
>>  	if (backend && strcmp(backend, psi->name)) {
>> -		pr_warn("ignoring unexpected backend '%s'\n", psi->name);
>> -		return -EPERM;
>> +		pr_warn("backend '%s' already in use: ignoring '%s'\n",
>> +			backend, psi->name);
>> +		return -EBUSY;
> 
> Thank you! Yes, this has bothered me for a while. :)

Heheh ditto! Thank you for the great and fast review =)