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From: Gao Xiang <hsiangkao@aol.com>
To: Eric Biggers <ebiggers@kernel.org>
Cc: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-f2fs-devel@lists.sourceforge.net,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Daniel Rosenberg <drosen@google.com>,
	Gabriel Krisman Bertazi <krisman@collabora.com>
Subject: Re: [PATCH] ext4: fix race conditions in ->d_compare() and ->d_hash()
Date: Fri, 24 Jan 2020 13:34:23 +0800	[thread overview]
Message-ID: <20200124053415.GC31271@hsiangkao-HP-ZHAN-66-Pro-G1> (raw)
In-Reply-To: <20200124051601.GB832@sol.localdomain>

On Thu, Jan 23, 2020 at 09:16:01PM -0800, Eric Biggers wrote:

[]

> So we need READ_ONCE() to ensure that a consistent value is used.

By the way, my understanding is all pointer could be accessed
atomicly guaranteed by compiler. In my opinion, we generally
use READ_ONCE() on pointers for other uses (such as, avoid
accessing a variable twice due to compiler optimization and
it will break some logic potentially or need some data
dependency barrier...)

Thanks,
Gao Xiang



  parent reply	other threads:[~2020-01-24  5:34 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-24  4:12 [PATCH] ext4: fix race conditions in ->d_compare() and ->d_hash() Eric Biggers
2020-01-24  5:04 ` Gao Xiang
2020-01-24  5:16   ` Eric Biggers
2020-01-24  5:27     ` Gao Xiang
2020-01-24  5:53       ` Eric Biggers
2020-01-24  5:34     ` Gao Xiang [this message]
2020-01-24  5:42       ` Eric Biggers
2020-01-24  6:15         ` Gao Xiang
2020-01-24 18:12           ` Eric Biggers
2020-01-24 18:31             ` Al Viro
2020-01-25  3:35 ` Theodore Y. Ts'o

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