linux-kernel - Re: Re: [PATCH v2] io_uring: releasing CPU resources when polling

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Date: Tue, 23 Apr 2024 11:31:47 +0800
From: hexue <xue01.he@...sung.com>
To: ammarfaizi2@...weeb.org
Cc: anuj20.g@...sung.com, asml.silence@...il.com, axboe@...nel.dk,
	cliang01.li@...sung.com, io-uring@...r.kernel.org, joshi.k@...sung.com,
	kundan.kumar@...sung.com, linux-kernel@...r.kernel.org,
	peiwei.li@...sung.com, ruyi.zhang@...sung.com, wenwen.chen@...sung.com,
	xiaobing.li@...sung.com, xue01.he@...sung.com
Subject: Re: Re: [PATCH v2] io_uring: releasing CPU resources when polling

On Mon, Apr 19, 2024 at 16:09 Ammar Faizi wrote:
>On Fri, Apr 19, 2024 at 3:47 PM hexue wrote:
>> +void init_hybrid_poll_info(struct io_ring_ctx *ctx, struct io_kiocb *req)
>> +{
>> +       u32 index;
>> +
>> +       index = req->file->f_inode->i_rdev;
>> +       struct iopoll_info *entry = xa_load(&ctx->poll_array, index);
>> +
>> +       if (!entry) {
>> +               entry = kmalloc(sizeof(struct iopoll_info), GFP_KERNEL);
>> +               entry->last_runtime = 0;
>> +               entry->last_irqtime = 0;
>> +               xa_store(&ctx->poll_array, index, entry, GFP_KERNEL);
>> +       }
>
>GFP_KERNEL may fail; you must check for failure. Otherwise, it could
>lead to NULL pointer dereference.
>

yes, thanks for your correction, I will fix this and resubmit v3 patch.