From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bmailout3.hostsharing.net (bmailout3.hostsharing.net [176.9.242.62]) (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 100D3155CBD; Mon, 23 Jun 2025 06:43:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=176.9.242.62 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750661018; cv=none; b=pW8rnZ3sgG96e/oIkeH9DfNn2CkqIVgoyaFG2ywdqnZjEcsMSHNiG7X2lcgG3Exz7pXNsp3nJK4YjfyexQOD0iXJxjWCUk9UwID4HBu4oO9K3TrvLHxCpb+ggFYsBSQ4Ws35XfTbj1kDfA4IG2AMTtXaUXHbNW1jmp5IB1OQWB8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750661018; c=relaxed/simple; bh=9PdGgbGKKUnTTw/LJl5rGRpxzu/5LUDwbLFp/xtn7b8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=TmdmpsY4tY/mYjcvSktotDA7cQAFUEb5mpsQV0sLFQUtuorBzTumhQfQ8GdEjXnfz3VeIugvHQDH3/YT1M94xuVqdJ7+0lJdnwC5dv805xQzkBf5NsOnGa+cozZL2HfqBOFhOCwVmxQOarRSX8M8zcZevXA88q4U6fOEdi9ZUsc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=wunner.de; spf=none smtp.mailfrom=h08.hostsharing.net; arc=none smtp.client-ip=176.9.242.62 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=wunner.de Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=h08.hostsharing.net Received: from h08.hostsharing.net (h08.hostsharing.net [83.223.95.28]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "*.hostsharing.net", Issuer "RapidSSL TLS RSA CA G1" (verified OK)) by bmailout3.hostsharing.net (Postfix) with ESMTPS id 053E62C00093; Mon, 23 Jun 2025 08:43:26 +0200 (CEST) Received: by h08.hostsharing.net (Postfix, from userid 100393) id D8717100451; Mon, 23 Jun 2025 08:43:25 +0200 (CEST) Date: Mon, 23 Jun 2025 08:43:25 +0200 From: Lukas Wunner To: Mario Limonciello Cc: Bjorn Helgaas , "open list:PCI SUBSYSTEM" , linux-pm@vger.kernel.org, "Rafael J . Wysocki" , Mario Limonciello Subject: Re: [PATCH v3 2/2] PCI: Fix runtime PM usage count underflow on device unplug Message-ID: References: <20250620025535.3425049-1-superm1@kernel.org> <20250620025535.3425049-3-superm1@kernel.org> <8d4d98b6-fec5-466f-bd2c-059d702c7860@kernel.org> <295bf182-7fed-4ffd-93a4-fb5ddf5f1bb4@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@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: <295bf182-7fed-4ffd-93a4-fb5ddf5f1bb4@kernel.org> On Sun, Jun 22, 2025 at 01:39:26PM -0500, Mario Limonciello wrote: > > > On 6/21/25 2:05 PM, Lukas Wunner wrote: > > > > So the refcount decrement happens in pcie_portdrv_probe() and > > > > the refcount increment happens in pcie_portdrv_remove(). > > > > Both times it's conditional on pci_bridge_d3_possible(). > > > > Does that return a different value on probe versus remove? > > I did this check and yes specifically on this PCIe port with the underflow > the d3 possible lookup returns false during pcie_portdrv_remove(). It > returns true during pcie_portdrv_probe(). That's not supposed to happen. The expectation is that pci_bridge_d3_possible() always returns the same value. For this reason the return value on ->probe() isn't cached. So which of the conditions changes in pci_bridge_d3_possible() on probe versus remove? Could you instrument each with a printk() so that we can understand what's going wrong there? Thanks, Lukas