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Sat, 27 Jun 2026 03:47:06 -0700 (PDT) Received: from Abds-MacBook-Air.local ([141.2.113.129]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-471490336d5sm3421142f8f.35.2026.06.27.03.47.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 27 Jun 2026 03:47:05 -0700 (PDT) From: Abd-Alrhman Masalkhi To: Chen Cheng , linux-raid@vger.kernel.org, yukuai@fygo.io Cc: chencheng@fnnas.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] md: protect read mddev->recovery in md_sync_action() In-Reply-To: <20260627102909.141036-1-chencheng@fnnas.com> Precedence: bulk X-Mailing-List: linux-raid@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain References: <20260627102909.141036-1-chencheng@fnnas.com> Hi Chen, Date: Sat, 27 Jun 2026 12:46:51 +0200 Message-ID: On Sat, Jun 27, 2026 at 18:29 +0800, Chen Cheng wrote: > From: Chen Cheng > > md_sync_action() read mddev->recovery in lockless path, use READ_ONCE() > instead of u64 plain read. > unisgned long is not always u64... I can not see what it fixes, is this just to silence KCSAN? If so, please say so in the commit message. > Fixes: e792a4c2156a3 ("md: add new helpers for sync_action") > > Signed-off-by: Chen Cheng > --- > drivers/md/md.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/md/md.c b/drivers/md/md.c > index c5c50640b684..f4415c1a79d9 100644 > --- a/drivers/md/md.c > +++ b/drivers/md/md.c > @@ -5074,11 +5074,11 @@ static enum sync_action md_get_active_sync_action(struct mddev *mddev) > return is_recover ? ACTION_RECOVER : ACTION_IDLE; > } > > enum sync_action md_sync_action(struct mddev *mddev) > { > - unsigned long recovery = mddev->recovery; > + unsigned long recovery = READ_ONCE(mddev->recovery); > enum sync_action active_action; > > /* > * frozen has the highest priority, means running sync_thread will be > * stopped immediately, and no new sync_thread can start. > -- > 2.54.0 > -- Best Regards, Abd-Alrhman