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[103.168.172.200]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-471ea7af88fsm9840941cf.69.2025.02.16.18.35.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 16 Feb 2025 18:35:14 -0800 (PST) Received: from phl-compute-06.internal (phl-compute-06.phl.internal [10.202.2.46]) by mailfauth.phl.internal (Postfix) with ESMTP id DB3471200043; Sun, 16 Feb 2025 21:35:13 -0500 (EST) Received: from phl-mailfrontend-02 ([10.202.2.163]) by phl-compute-06.internal (MEProxy); Sun, 16 Feb 2025 21:35:13 -0500 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgdehjedujecutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpggftfghnshhusghstghrihgsvgdp uffrtefokffrpgfnqfghnecuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivg hnthhsucdlqddutddtmdenucfjughrpeffhffvvefukfhfgggtuggjsehttdertddttddv necuhfhrohhmpeeuohhquhhnucfhvghnghcuoegsohhquhhnrdhfvghnghesghhmrghilh drtghomheqnecuggftrfgrthhtvghrnhephfetvdfgtdeukedvkeeiteeiteejieehvdet heduudejvdektdekfeegvddvhedtnecuffhomhgrihhnpehkvghrnhgvlhdrohhrghenuc evlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpegsohhquhhn odhmvghsmhhtphgruhhthhhpvghrshhonhgrlhhithihqdeiledvgeehtdeigedqudejje ekheehhedvqdgsohhquhhnrdhfvghngheppehgmhgrihhlrdgtohhmsehfihigmhgvrdhn rghmvgdpnhgspghrtghpthhtohepkedpmhhouggvpehsmhhtphhouhhtpdhrtghpthhtoh epmhhmphhgohhurhhiuggvsehgmhgrihhlrdgtohhmpdhrtghpthhtoheprhhitghhrghr ugdrfigvihihrghnghesghhmrghilhdrtghomhdprhgtphhtthhopehprghulhhmtghkse hkvghrnhgvlhdrohhrghdprhgtphhtthhopehfrhgvuggvrhhitgeskhgvrhhnvghlrdho rhhgpdhrtghpthhtohepnhgvvghrrghjrdhuphgrughhhigrhieskhgvrhhnvghlrdhorh hgpdhrtghpthhtoheprhgtuhesvhhgvghrrdhkvghrnhgvlhdrohhrghdprhgtphhtthho pehlihhnuhigqdguohgtsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtohepsg hoqhhunhesfhhigihmvgdrnhgrmhgv X-ME-Proxy: Feedback-ID: iad51458e:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Sun, 16 Feb 2025 21:35:13 -0500 (EST) Date: Sun, 16 Feb 2025 18:35:12 -0800 From: Boqun Feng To: Alan Huang Cc: Wei Yang , paulmck@kernel.org, frederic@kernel.org, neeraj.upadhyay@kernel.org, rcu@vger.kernel.org, linux-doc@vger.kernel.org Subject: Re: [PATCH] doc/RCU/listRCU: fix an example code snippets Message-ID: References: <20250101082306.10404-1-richard.weiyang@gmail.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Mon, Feb 17, 2025 at 10:22:53AM +0800, Alan Huang wrote: > On Feb 17, 2025, at 10:12, Boqun Feng wrote: > > > > Hi Wei, > > > > The change loosk good to me, thanks! > > > > I queued the patch for futher reviews and tests with some changes in the > > commit log (for title formating and a bit more explanation), please see > > below. > > > > Regards, > > Boqun > > > > On Wed, Jan 01, 2025 at 08:23:06AM +0000, Wei Yang wrote: > >> The example code for "Eliminating Stale Data" looks not correct: > >> > >> * rcu_read_unlock() should put after kstrdup() > >> * spin_unlock() should be called before return > >> > >> Signed-off-by: Wei Yang > > [...] > > > > > > ------------------>8 > > Subject: [PATCH] doc/RCU/listRCU: Fix an example code snippets > > > > The example code for "Eliminating Stale Data" looks not correct: > > > > * rcu_read_unlock() should put after kstrdup(), because otherwise > > entry may get freed while kstrdup() is being called. > > > > * spin_unlock() should be called before return, otherwise the > > function would return with the lock of the entry held. > > > > Hence fix these. > > > > Signed-off-by: Wei Yang > > Link: https://lore.kernel.org/r/20250101082306.10404-1-richard.weiyang@gmail.com > > Signed-off-by: Boqun Feng > > --- > > Documentation/RCU/listRCU.rst | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/Documentation/RCU/listRCU.rst b/Documentation/RCU/listRCU.rst > > index ed5c9d8c9afe..8df50fcd69fd 100644 > > --- a/Documentation/RCU/listRCU.rst > > +++ b/Documentation/RCU/listRCU.rst > > @@ -348,9 +348,10 @@ to accomplish this would be to add a ``deleted`` flag and a ``lock`` spinlock to > > rcu_read_unlock(); > > return AUDIT_BUILD_CONTEXT; > > } > > - rcu_read_unlock(); > > if (state == AUDIT_STATE_RECORD) > > *key = kstrdup(e->rule.filterkey, GFP_ATOMIC); > > + spin_unlock(&e->lock); > > According to the above quick quiz, we should return with the lock held. > Good catch! I think we then don't need this patch? Wei, are you able to confirm Alan's reasoning here? Regards, Boqun > > + rcu_read_unlock(); > > return state; > > } > > } > > -- > > >