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Date: Wed, 27 Aug 2025 15:59:23 -0600
From: Keith Busch <kbusch@kernel.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: Qingyue Zhang <chunzhennn@qq.com>, io-uring@vger.kernel.org,
	linux-kernel@vger.kernel.org, Suoxing Zhang <aftern00n@qq.com>
Subject: Re: [PATCH 2/2] io_uring/kbuf: fix infinite loop in
 io_kbuf_inc_commit()
Message-ID: <aK9_u9ZK9NgKiBkE@kbusch-mbp>
References: <20250827114339.367080-1-chunzhennn@qq.com>
 <tencent_000C02641F6250C856D0C26228DE29A3D30A@qq.com>
 <fcfd5324-9918-4613-94b0-c27fb8398375@kernel.dk>
 <4b8eb795-239f-4f46-af4f-7a05056ab516@kernel.dk>
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In-Reply-To: <4b8eb795-239f-4f46-af4f-7a05056ab516@kernel.dk>

On Wed, Aug 27, 2025 at 03:45:28PM -0600, Jens Axboe wrote:
> > +		buf_len = READ_ONCE(buf->len);
> > +		this_len = min_t(int, len, buf_len);
> > +		buf_len -= this_len;
> > +		if (buf_len) {
> >  			buf->addr += this_len;
> > +			buf->len = buf_len;
> >  			return false;
> >  		}
> > +		buf->len = 0;

Purely for symmetry, assigning buf->len ought to be a WRITE_ONCE.