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 E76501B6D06; Sun, 24 Nov 2024 13:38:32 +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=1732455513; cv=none; b=i3TuKM8Fm0nflLINp4i8tKlntGL0JvFW+WwOc1n8MLU9iMZTUGjSHyyXVMM6rq0vXS0g54CmB0kwYtZmTqJsnreDncQ//x6ipoeuJM1qZIft82wGS8aPC6moEmPwJwF6CA02DEdrvr7Isdxj/97r4xU+7R81SqnwrX6hlE7iv94= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732455513; c=relaxed/simple; bh=frMsR8PTOxaQrnnDp39CBVkRcossL8PMqqCmGH4P73Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=O/txAO0L2wVzt7TNyCwrRd3QYVOlvoOISS0hDk8yPnRlxdCLp9eL5m6sktlpovYdEds5LRbT09BPvwdkYOOHZngjZwoP3/KxwuAujTC5VWUZdDXDYaXU+ovO4ooNhNKbvbNvjFqpNgJAP9bGki2VlJQbpuJ4e3sCx/B+EDv21cQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nh6ibUH1; 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="nh6ibUH1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C4A58C4CECC; Sun, 24 Nov 2024 13:38:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1732455512; bh=frMsR8PTOxaQrnnDp39CBVkRcossL8PMqqCmGH4P73Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nh6ibUH1SFeSwpHTXGM1Q461jDjwOa5XJAxLJsYc1ucdNO6bA35g9OMqAkhQgtWy8 pVsMCR3Z/llZssNhclF4sysUviiQlrzyaFNlWdPV6pRpFWsGhs5swvEGReQxlV/sAh MYSu67OKmDz9svI1sIc2MMrahQmWHorjoXPY9SDNIzUD4Nox4Azatzh5xAWeOSXhTz jr8lMdERmCW3p8q6QoydZSaSIImbJOkTpSMPgpI0ttEvRqA7xlQCuuZoJrsa0JNzI3 5wipk0oevZGyAPxLZVcQ3waWn+jXk/z94oNhcbfQxwYQVcWov2u/GgEaO+k12418i3 bNA4vpVG3kZRA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Andrew Lunn , Jakub Kicinski , Sasha Levin , olteanv@gmail.com, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, florian.fainelli@broadcom.com, alsi@bang-olufsen.dk, luizluca@gmail.com, michal.vokac@ysoft.com, rmk+kernel@armlinux.org.uk, javier.carrasco.cruz@gmail.com, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 6.12 091/107] dsa: qca8k: Use nested lock to avoid splat Date: Sun, 24 Nov 2024 08:29:51 -0500 Message-ID: <20241124133301.3341829-91-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241124133301.3341829-1-sashal@kernel.org> References: <20241124133301.3341829-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.12.1 Content-Transfer-Encoding: 8bit From: Andrew Lunn [ Upstream commit 078e0d596f7b5952dad8662ace8f20ed2165e2ce ] qca8k_phy_eth_command() is used to probe the child MDIO bus while the parent MDIO is locked. This causes lockdep splat, reporting a possible deadlock. It is not an actually deadlock, because different locks are used. By making use of mutex_lock_nested() we can avoid this false positive. Signed-off-by: Andrew Lunn Link: https://patch.msgid.link/20241110175955.3053664-1-andrew@lunn.ch Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/dsa/qca/qca8k-8xxx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/dsa/qca/qca8k-8xxx.c b/drivers/net/dsa/qca/qca8k-8xxx.c index f8d8c70642c4f..59b4a7240b583 100644 --- a/drivers/net/dsa/qca/qca8k-8xxx.c +++ b/drivers/net/dsa/qca/qca8k-8xxx.c @@ -673,7 +673,7 @@ qca8k_phy_eth_command(struct qca8k_priv *priv, bool read, int phy, * We therefore need to lock the MDIO bus onto which the switch is * connected. */ - mutex_lock(&priv->bus->mdio_lock); + mutex_lock_nested(&priv->bus->mdio_lock, MDIO_MUTEX_NESTED); /* Actually start the request: * 1. Send mdio master packet -- 2.43.0