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 <20240418093143.2188131-1-xue01.he@samsung.com>
In-Reply-To: <20240418093143.2188131-1-xue01.he@samsung.com>
From: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Date: Fri, 19 Apr 2024 16:09:56 +0700
Message-ID: <CAFBCWQJAjef4AGXmVDZ-dR02zqstpXuP_mWimsF5HQCMxxeCcg@mail.gmail.com>
Subject: Re: [PATCH v2] io_uring: releasing CPU resources when polling
To: hexue <xue01.he@samsung.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, 
	io-uring Mailing List <io-uring@vger.kernel.org>, Jens Axboe <axboe@kernel.dk>, 
	Pavel Begunkov <asml.silence@gmail.com>, Kanchan Joshi <joshi.k@samsung.com>, 
	Kundan Kumar <kundan.kumar@samsung.com>, Anuj Gupta <anuj20.g@samsung.com>, 
	Wenwen Chen <wenwen.chen@samsung.com>, Ruyi Zhang <ruyi.zhang@samsung.com>, 
	Xiaobing Li <xiaobing.li@samsung.com>, cliang01.li@samsung.com, peiwei.li@samsung.com
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On Fri, Apr 19, 2024 at 3:47=E2=80=AFPM hexue wrote:
> +void init_hybrid_poll_info(struct io_ring_ctx *ctx, struct io_kiocb *req=
)
> +{
> +       u32 index;
> +
> +       index =3D req->file->f_inode->i_rdev;
> +       struct iopoll_info *entry =3D xa_load(&ctx->poll_array, index);
> +
> +       if (!entry) {
> +               entry =3D kmalloc(sizeof(struct iopoll_info), GFP_KERNEL)=
;
> +               entry->last_runtime =3D 0;
> +               entry->last_irqtime =3D 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.

--=20
Ammar Faizi