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 60D48134A4 for ; Mon, 12 Jun 2023 10:44:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DD714C433EF; Mon, 12 Jun 2023 10:44:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1686566642; bh=eHqA/XNTgPzNyWaSNWkVQYCmkusbEx6uTjAX+yi3Nxk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HfvVFls+LYcEY7KLFLAx0zu4sm17NLszqxCawuPoPig59esamP1kqF9Wtqn4PQqxc eh7Za1Kq/V10rQMGp0a3CnI/r9CK7li2JSMyZNli7N8fjSF9z5XHZxM5hlwCDR8m9/ lBsFYtQXvh2reylrYu+eqHqicZscHB/tAyLEwpYE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Claudiu Beznea , Nicolas Ferre , Sasha Levin Subject: [PATCH 6.1 102/132] ARM: at91: pm: fix imbalanced reference counter for ethernet devices Date: Mon, 12 Jun 2023 12:27:16 +0200 Message-ID: <20230612101714.946062577@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230612101710.279705932@linuxfoundation.org> References: <20230612101710.279705932@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Claudiu Beznea [ Upstream commit ccd4923d18d5698a5910d516646ce125b9155d47 ] The of_find_device_by_node() function is returning a struct platform_device object with the embedded struct device member's reference counter incremented. This needs to be dropped when done with the platform device returned by of_find_device_by_node(). at91_pm_eth_quirk_is_valid() calls of_find_device_by_node() on suspend and resume path. On suspend it calls of_find_device_by_node() and on resume and failure paths it drops the counter of struct platform_device::dev. In case ethernet device may not wakeup there is a put_device() on at91_pm_eth_quirk_is_valid() which is wrong as it colides with put_device() on resume path leading to the reference counter of struct device embedded in struct platform_device to be messed, stack trace to be displayed (after 5 consecutive suspend/resume cycles) and execution to hang. Along with this the error path of at91_pm_config_quirks() had been also adapted to decrement propertly the reference counter of struct device embedded in struct platform_device. Fixes: b7fc72c63399 ("ARM: at91: pm: add quirks for pm") Signed-off-by: Claudiu Beznea Acked-by: Nicolas Ferre Link: https://lore.kernel.org/r/20230518062511.2988500-1-claudiu.beznea@microchip.com Signed-off-by: Sasha Levin --- arch/arm/mach-at91/pm.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c index 60dc56d8acfb9..437dd0352fd44 100644 --- a/arch/arm/mach-at91/pm.c +++ b/arch/arm/mach-at91/pm.c @@ -334,16 +334,14 @@ static bool at91_pm_eth_quirk_is_valid(struct at91_pm_quirk_eth *eth) pdev = of_find_device_by_node(eth->np); if (!pdev) return false; + /* put_device(eth->dev) is called at the end of suspend. */ eth->dev = &pdev->dev; } /* No quirks if device isn't a wakeup source. */ - if (!device_may_wakeup(eth->dev)) { - put_device(eth->dev); + if (!device_may_wakeup(eth->dev)) return false; - } - /* put_device(eth->dev) is called at the end of suspend. */ return true; } @@ -439,14 +437,14 @@ static int at91_pm_config_quirks(bool suspend) pr_err("AT91: PM: failed to enable %s clocks\n", j == AT91_PM_G_ETH ? "geth" : "eth"); } - } else { - /* - * Release the reference to eth->dev taken in - * at91_pm_eth_quirk_is_valid(). - */ - put_device(eth->dev); - eth->dev = NULL; } + + /* + * Release the reference to eth->dev taken in + * at91_pm_eth_quirk_is_valid(). + */ + put_device(eth->dev); + eth->dev = NULL; } return ret; -- 2.39.2