From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 27D6C219485; Sun, 24 Nov 2024 13:45:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732455935; cv=none; b=nx164lvyDVpLzHiGHKBjeE+Fc/bBu3Jq7XJ48ui4v+8swnwGTfiFdaIBkVrsYTDyg7P1EoM9OENjoTBH/qzGDFzBbOQux62J0ziSpmooOSbSkI0zyXLOiCuAbnqnMC8oeP6GiTttp3bHI9au5+qTUadl5/WpnlLty92r2B6SyDw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732455935; c=relaxed/simple; bh=7R/4zkp3mmqZEvUlmwUoJEtoNU7zMbodl275S1AVnKk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BMkQXaqz01HDYC+8Ht084SR60P3K9qi8NFn7ikAG2FQ8HV5mShNEX98hPFzGVonPCitCkGAszBuhZcm4zU/RwOLkLR+LVI/RMsxj82TQ7FNZzIkEKNeMfe052Doq/Lffnqs2ERTo0LFI+0Rez9SiziLjbINWGUQk+vtwpafj4f8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pRt22F7M; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="pRt22F7M" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B3D54C4CED1; Sun, 24 Nov 2024 13:45:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1732455935; bh=7R/4zkp3mmqZEvUlmwUoJEtoNU7zMbodl275S1AVnKk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pRt22F7MEzT3n4T8Y+s7I9PV8fFI9bZ23lvrGyCHP0m6HH6b46l0a5L4578R985B3 xYMksQH4rilJwrfKMb7HGEF0h2dJ+9gVsJfn61YMu7/4jHoI7yofew8xgfGb/92I9d hIm7FBIVBQiseR1ibxuHq1NAiFDXvUzYkGTuuZzc6F11FGGUzYfhdvWuuYoXM1w0Do s0MaBep+9xQNtlbC1HAnG3FHHztMsv+pJkRv7Fqkr9u3wrJPxKXCuD/wfPDMUNejhU y3+6I+dFNmAjJj8wXF4UGmx/V7M9GEDtkmYvU6XL5R39yUXWck5u8X2cku5yLubkJq OQYC47ZlS4k3Q== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Breno Leitao , Michal Kubiak , Jakub Kicinski , Sasha Levin , davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, horms@kernel.org, viro@zeniv.linux.org.uk, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 6.11 87/87] netpoll: Use rcu_access_pointer() in __netpoll_setup Date: Sun, 24 Nov 2024 08:39:05 -0500 Message-ID: <20241124134102.3344326-87-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241124134102.3344326-1-sashal@kernel.org> References: <20241124134102.3344326-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.11.10 Content-Transfer-Encoding: 8bit From: Breno Leitao [ Upstream commit c69c5e10adb903ae2438d4f9c16eccf43d1fcbc1 ] The ndev->npinfo pointer in __netpoll_setup() is RCU-protected but is being accessed directly for a NULL check. While no RCU read lock is held in this context, we should still use proper RCU primitives for consistency and correctness. Replace the direct NULL check with rcu_access_pointer(), which is the appropriate primitive when only checking for NULL without dereferencing the pointer. This function provides the necessary ordering guarantees without requiring RCU read-side protection. Reviewed-by: Michal Kubiak Signed-off-by: Breno Leitao Link: https://patch.msgid.link/20241118-netpoll_rcu-v1-1-a1888dcb4a02@debian.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/core/netpoll.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 930acc87c8c08..d2f8d07ca5cfd 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -631,7 +631,7 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev) goto out; } - if (!ndev->npinfo) { + if (!rcu_access_pointer(ndev->npinfo)) { npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL); if (!npinfo) { err = -ENOMEM; -- 2.43.0