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Subject: Re: [PATCH 7/7] sysvipc_find_ipc should increase position index
To:     linux-kernel@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     Waiman Long <longman@redhat.com>
References: <b7a20945-e315-8bb0-21e6-3875c14a8494@virtuozzo.com>
 <8ed2850e-7cec-ebeb-4e15-21da3715c42a@redhat.com>
From:   Vasily Averin <vvs@virtuozzo.com>
Message-ID: <8e097c72-5fd0-4a59-12e3-8298b9f5468e@virtuozzo.com>
Date:   Tue, 25 Feb 2020 09:35:34 +0300
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Dear Andrew,
Could you please pick up this patch?

On 1/24/20 7:26 PM, Waiman Long wrote:
> On 1/24/20 2:03 AM, Vasily Averin wrote:
>> if seq_file .next fuction does not change position index,
>> read after some lseek can generate unexpected output.
>>
>> https://bugzilla.kernel.org/show_bug.cgi?id=206283
>> Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
>> ---
>>  ipc/util.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/ipc/util.c b/ipc/util.c
>> index 915eacb..7a3ab2e 100644
>> --- a/ipc/util.c
>> +++ b/ipc/util.c
>> @@ -764,13 +764,13 @@ static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos,
>>  			total++;
>>  	}
>>  
>> +	*new_pos = pos + 1;
>>  	if (total >= ids->in_use)
>>  		return NULL;
>>  
>>  	for (; pos < ipc_mni; pos++) {
>>  		ipc = idr_find(&ids->ipcs_idr, pos);
>>  		if (ipc != NULL) {
>> -			*new_pos = pos + 1;
>>  			rcu_read_lock();
>>  			ipc_lock_object(ipc);
>>  			return ipc;
> 
> Acked-by: Waiman Long <longman@redhat.com>
>