From patchwork Wed Nov 3 13:56:35 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Frank Heimes X-Patchwork-Id: 1550287 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: bilbo.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=canonical.com header.i=@canonical.com header.a=rsa-sha256 header.s=20210705 header.b=iRVfKKTB; dkim-atps=neutral Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lists.ubuntu.com (client-ip=91.189.94.19; helo=huckleberry.canonical.com; envelope-from=kernel-team-bounces@lists.ubuntu.com; receiver=) Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by bilbo.ozlabs.org (Postfix) with ESMTPS id 4HkpJ01ZFGz9sXS for ; Thu, 4 Nov 2021 00:57:51 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.86_2) (envelope-from ) id 1miGlq-0000ZR-TF; Wed, 03 Nov 2021 13:57:42 +0000 Received: from smtp-relay-canonical-1.internal ([10.131.114.174] helo=smtp-relay-canonical-1.canonical.com) by huckleberry.canonical.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1miGlo-0000Yr-AU for kernel-team@lists.ubuntu.com; Wed, 03 Nov 2021 13:57:40 +0000 Received: from T570.fritz.box (p54abb560.dip0.t-ipconnect.de [84.171.181.96]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by smtp-relay-canonical-1.canonical.com (Postfix) with ESMTPSA id 209193F1CD for ; Wed, 3 Nov 2021 13:57:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=canonical.com; s=20210705; t=1635947860; bh=4F+d0/Ihkn3MJ9gLbjbf8N4rJq5CWuAWg8In/m4iMRY=; h=From:To:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=iRVfKKTBW1sbxK8Qm775RR4v1Wt62w9nlOV//t59EMGkqMT+k2F+42WOQsCeq8tXG hISCol+ftNAe1Fj/pQ2oDeFP6zTOyvMhyiY7Axsbl/cBXjPFRZ77W+kMZc+x6zEtkU 08GZE5o1v/rVSZ40aGPAOkAJdF2tzaDv2ECBcPF9PIlpne1TPNITgFMuDtKxaA0N2C 03JGQlmyGw0Fz0qxe1zg4JYiWoiW8Slix+5rN3yqugGPguWYqoLmouz1H+nmTtfazv LfXhilmWSPEJiK81oc53CRCv22F90sK5b+LRH217b012GKCZBroMZIMh3Vzn1i1Szh oUFbDX67kRZkA== From: frank.heimes@canonical.com To: kernel-team@lists.ubuntu.com Subject: [SRU][F][PATCH 1/3] s390/pci: fix leak of PCI device structure Date: Wed, 3 Nov 2021 14:56:35 +0100 Message-Id: <20211103135637.2220305-2-frank.heimes@canonical.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211103135637.2220305-1-frank.heimes@canonical.com> References: <20211103135637.2220305-1-frank.heimes@canonical.com> MIME-Version: 1.0 X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.20 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: "kernel-team" From: Niklas Schnelle BugLink: https://bugs.launchpad.net/bugs/1943464 In commit 05bc1be6db4b2 ("s390/pci: create zPCI bus") we removed the pci_dev_put() call matching the earlier pci_get_slot() done as part of __zpci_event_availability(). This was based on the wrong understanding that the device_put() done as part of pci_destroy_device() would counter the pci_get_slot() when it only counters the initial reference. This same understanding and existing bad example also lead to not doing a pci_dev_put() in zpci_remove_device(). Since releasing the PCI devices, unlike releasing the PCI slot, does not print any debug message for testing I added one in pci_release_dev(). This revealed that we are indeed leaking the PCI device on PCI hotunplug. Further testing also revealed another missing pci_dev_put() in disable_slot(). Fix this by adding the missing pci_dev_put() in disable_slot() and fix zpci_remove_device() with the correct pci_dev_put() calls. Also instead of calling pci_get_slot() in __zpci_event_availability() to determine if a PCI device is registered and then doing the same again in zpci_remove_device() do this once in zpci_remove_device() which makes sure that the pdev in __zpci_event_availability() is only used for the result of pci_scan_single_device() which does not need a reference count decremnt as its ownership goes to the PCI bus. Also move the check if zdev->zbus->bus is set into zpci_remove_device() since it may be that we're removing a device with devfn != 0 which never had a PCI bus. So we can still set the pdev->error_state to indicate that the device is not usable anymore, add a flag to set the error state. Fixes: 05bc1be6db4b2 ("s390/pci: create zPCI bus") Cc: # 5.8+: e1bff843cde6 s390/pci: remove superfluous zdev->zbus check Cc: # 5.8+: ba764dd703fe s390/pci: refactor zpci_create_device() Cc: # 5.8+ Reviewed-by: Matthew Rosato Signed-off-by: Niklas Schnelle Signed-off-by: Heiko Carstens (backported from commit 0b13525c20febcfecccf6fc1db5969727401317d) Signed-off-by: Frank Heimes --- arch/s390/include/asm/pci.h | 4 ++-- arch/s390/pci/pci.c | 28 ++++++++++++++++++++++++---- arch/s390/pci/pci_event.c | 18 ++++++------------ drivers/pci/hotplug/s390_pci_hpc.c | 3 ++- 4 files changed, 34 insertions(+), 19 deletions(-) diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h index ea0daab3eb80..5bcac3ac872d 100644 --- a/arch/s390/include/asm/pci.h +++ b/arch/s390/include/asm/pci.h @@ -201,8 +201,8 @@ extern unsigned int s390_pci_no_rid; Prototypes ----------------------------------------------------------------------------- */ /* Base stuff */ -int zpci_create_device(struct zpci_dev *); -void zpci_remove_device(struct zpci_dev *zdev); +int zpci_create_device(struct zpci_dev *zdev); +void zpci_remove_device(struct zpci_dev *zdev, bool set_error); int zpci_enable_device(struct zpci_dev *); int zpci_disable_device(struct zpci_dev *); int zpci_register_ioat(struct zpci_dev *, u8, u64, u64, u64); diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c index 55b7a8a48940..5e9b6b2185c9 100644 --- a/arch/s390/pci/pci.c +++ b/arch/s390/pci/pci.c @@ -717,16 +717,36 @@ int zpci_disable_device(struct zpci_dev *zdev) } EXPORT_SYMBOL_GPL(zpci_disable_device); -void zpci_remove_device(struct zpci_dev *zdev) +/* zpci_remove_device - Removes the given zdev from the PCI core + * @zdev: the zdev to be removed from the PCI core + * @set_error: if true the device's error state is set to permanent failure + * + * Sets a zPCI device to a configured but offline state; the zPCI + * device is still accessible through its hotplug slot and the zPCI + * API but is removed from the common code PCI bus, making it + * no longer available to drivers. + */ +void zpci_remove_device(struct zpci_dev *zdev, bool set_error) { struct zpci_bus *zbus = zdev->zbus; struct pci_dev *pdev; + if (!zdev->zbus->bus) + return; + pdev = pci_get_slot(zbus->bus, zdev->devfn); if (pdev) { - if (pdev->is_virtfn) - return zpci_remove_virtfn(pdev, zdev->vfn); + if (set_error) + pdev->error_state = pci_channel_io_perm_failure; + if (pdev->is_virtfn) { + zpci_remove_virtfn(pdev, zdev->vfn); + /* balance pci_get_slot */ + pci_dev_put(pdev); + return; + } pci_stop_and_remove_bus_device_locked(pdev); + /* balance pci_get_slot */ + pci_dev_put(pdev); } } @@ -775,7 +795,7 @@ void zpci_release_device(struct kref *kref) struct zpci_dev *zdev = container_of(kref, struct zpci_dev, kref); if (zdev->zbus->bus) - zpci_remove_device(zdev); + zpci_remove_device(zdev, false); switch (zdev->state) { case ZPCI_FN_STATE_ONLINE: diff --git a/arch/s390/pci/pci_event.c b/arch/s390/pci/pci_event.c index 40a569b548cc..c5b7980ff937 100644 --- a/arch/s390/pci/pci_event.c +++ b/arch/s390/pci/pci_event.c @@ -76,13 +76,10 @@ void zpci_event_error(void *data) static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf) { struct zpci_dev *zdev = get_zdev_by_fid(ccdf->fid); - struct pci_dev *pdev = NULL; enum zpci_state state; + struct pci_dev *pdev; int ret; - if (zdev && zdev->zbus && zdev->zbus->bus) - pdev = pci_get_slot(zdev->zbus->bus, zdev->devfn); - zpci_err("avail CCDF:\n"); zpci_err_hex(ccdf, sizeof(*ccdf)); @@ -124,8 +121,7 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf) case 0x0303: /* Deconfiguration requested */ if (!zdev) break; - if (pdev) - zpci_remove_device(zdev); + zpci_remove_device(zdev, false); ret = zpci_disable_device(zdev); if (ret) @@ -140,12 +136,10 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf) case 0x0304: /* Configured -> Standby|Reserved */ if (!zdev) break; - if (pdev) { - /* Give the driver a hint that the function is - * already unusable. */ - pdev->error_state = pci_channel_io_perm_failure; - zpci_remove_device(zdev); - } + /* Give the driver a hint that the function is + * already unusable. + */ + zpci_remove_device(zdev, true); zdev->fh = ccdf->fh; zpci_disable_device(zdev); diff --git a/drivers/pci/hotplug/s390_pci_hpc.c b/drivers/pci/hotplug/s390_pci_hpc.c index c9e790c74051..a047c421debe 100644 --- a/drivers/pci/hotplug/s390_pci_hpc.c +++ b/drivers/pci/hotplug/s390_pci_hpc.c @@ -93,8 +93,9 @@ static int disable_slot(struct hotplug_slot *hotplug_slot) pci_dev_put(pdev); return -EBUSY; } + pci_dev_put(pdev); - zpci_remove_device(zdev); + zpci_remove_device(zdev, false); rc = zpci_disable_device(zdev); if (rc)