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Subject: Re: [PATCH v3] ocfs2: quota_local: fix possible
 uninitialized-variable access in ocfs2_local_read_info()
From:   Joseph Qi <joseph.qi@linux.alibaba.com>
To:     Tuo Li <islituo@gmail.com>, akpm <akpm@linux-foundation.org>
Cc:     ocfs2-devel@oss.oracle.com, linux-kernel@vger.kernel.org,
        baijiaju1990@gmail.com, TOTE Robot <oslab@tsinghua.edu.cn>,
        Joel Becker <jlbec@evilplan.org>, Mark Fasheh <mark@fasheh.com>
References: <20210804031832.57154-1-islituo@gmail.com>
 <d19dd958-93f6-bc42-b419-c60571de9b70@linux.alibaba.com>
Message-ID: <ee5f3d8b-3781-d04a-b379-40d4df6e1feb@linux.alibaba.com>
Date:   Thu, 19 Aug 2021 11:46:03 +0800
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Hi Andrew,
It seems you haven't picked this patch into -mm tree.
Should we resend it or it's fine now?

Thanks,
Joseph

On 8/4/21 11:26 AM, Joseph Qi wrote:
> 
> 
> On 8/4/21 11:18 AM, Tuo Li wrote:
>> A memory block is allocated through kmalloc(), and its return value is
>> assigned to the pointer oinfo. However, oinfo->dqi_gqinode is not
>> initialized but it is accessed in:
>>   iput(oinfo->dqi_gqinode);
>>
>> To fix this possible uninitialized-variable access, assign NULL to
>> oinfo->dqi_gqinode, and add ocfs2_qinfo_lock_res_init()
>> behind the assignment in ocfs2_local_read_info(). Remove
>> ocfs2_qinfo_lock_res_init() in ocfs2_global_read_info().
>>
> 
> Or we can simplify the above description to:
> "To fix the possible uninitialized-variable access, initialize
> dqi_gqinode and dqi_gqlock first before calling
> ocfs2_global_read_info()."
> 
>> Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
>> Signed-off-by: Tuo Li <islituo@gmail.com>
> 
> Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
>> ---
>> v3:
>> * Update description.
>> * Assign NULL to oinfo->dqi_gqinode, and add ocfs2_qinfo_lock_res_init()
>> behind the assignment in ocfs2_local_read_info(). Remove
>> ocfs2_qinfo_lock_res_init() in ocfs2_global_read_info()
>>   Thank Joseph Qi for helpful advice.
>> v2:
>> * Replace kzalloc() with NULL assignment to oinfo->dqi_gqinode.
>>   Thank Joseph Qi for helpful advice.
>> ---
>>  fs/ocfs2/quota_global.c | 1 -
>>  fs/ocfs2/quota_local.c  | 2 ++
>>  2 files changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/ocfs2/quota_global.c b/fs/ocfs2/quota_global.c
>> index eda83487c9ec..f033de733adb 100644
>> --- a/fs/ocfs2/quota_global.c
>> +++ b/fs/ocfs2/quota_global.c
>> @@ -357,7 +357,6 @@ int ocfs2_global_read_info(struct super_block *sb, int type)
>>  	}
>>  	oinfo->dqi_gi.dqi_sb = sb;
>>  	oinfo->dqi_gi.dqi_type = type;
>> -	ocfs2_qinfo_lock_res_init(&oinfo->dqi_gqlock, oinfo);
>>  	oinfo->dqi_gi.dqi_entry_size = sizeof(struct ocfs2_global_disk_dqblk);
>>  	oinfo->dqi_gi.dqi_ops = &ocfs2_global_ops;
>>  	oinfo->dqi_gqi_bh = NULL;
>> diff --git a/fs/ocfs2/quota_local.c b/fs/ocfs2/quota_local.c
>> index b1a8b046f4c2..0e4b16d4c037 100644
>> --- a/fs/ocfs2/quota_local.c
>> +++ b/fs/ocfs2/quota_local.c
>> @@ -702,6 +702,8 @@ static int ocfs2_local_read_info(struct super_block *sb, int type)
>>  	info->dqi_priv = oinfo;
>>  	oinfo->dqi_type = type;
>>  	INIT_LIST_HEAD(&oinfo->dqi_chunk);
>> +	oinfo->dqi_gqinode = NULL;
>> +	ocfs2_qinfo_lock_res_init(&oinfo->dqi_gqlock, oinfo);
>>  	oinfo->dqi_rec = NULL;
>>  	oinfo->dqi_lqi_bh = NULL;
>>  	oinfo->dqi_libh = NULL;
>>