6.12-stable review patch. If anyone has any objections, please let me know.
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From: Niklas Schnelle schnelle@linux.ibm.com
commit 48796104c864cf4dafa80bd8c2ce88f9c92a65ea upstream.
Prior to commit 0467cdde8c43 ("s390/pci: Sort PCI functions prior to creating virtual busses") the IOMMU was initialized and the device was registered as part of zpci_create_device() with the struct zpci_dev freed if either resulted in an error. With that commit this was moved into a separate function called zpci_add_device().
While this new function logs when adding failed, it expects the caller not to use and to free the struct zpci_dev on error. This difference between it and zpci_create_device() was missed while changing the callers and the incompletely initialized struct zpci_dev may get used in zpci_scan_configured_device in the error path. This then leads to a crash due to the device not being registered with the zbus. It was also not freed in this case. Fix this by handling the error return of zpci_add_device(). Since in this case the zdev was not added to the zpci_list it can simply be discarded and freed. Also make this more explicit by moving the kref_init() into zpci_add_device() and document that zpci_zdev_get()/zpci_zdev_put() must be used after adding.
Cc: stable@vger.kernel.org Fixes: 0467cdde8c43 ("s390/pci: Sort PCI functions prior to creating virtual busses") Reviewed-by: Gerd Bayer gbayer@linux.ibm.com Reviewed-by: Matthew Rosato mjrosato@linux.ibm.com Signed-off-by: Niklas Schnelle schnelle@linux.ibm.com Signed-off-by: Heiko Carstens hca@linux.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/s390/pci/pci.c | 21 +++++++++++++++++---- arch/s390/pci/pci_event.c | 10 ++++++++-- 2 files changed, 25 insertions(+), 6 deletions(-)
--- a/arch/s390/pci/pci.c +++ b/arch/s390/pci/pci.c @@ -779,8 +779,9 @@ int zpci_hot_reset_device(struct zpci_de * @fh: Current Function Handle of the device to be created * @state: Initial state after creation either Standby or Configured * - * Creates a new zpci device and adds it to its, possibly newly created, zbus - * as well as zpci_list. + * Allocates a new struct zpci_dev and queries the platform for its details. + * If successful the device can subsequently be added to the zPCI subsystem + * using zpci_add_device(). * * Returns: the zdev on success or an error pointer otherwise */ @@ -803,7 +804,6 @@ struct zpci_dev *zpci_create_device(u32 goto error; zdev->state = state;
- kref_init(&zdev->kref); mutex_init(&zdev->state_lock); mutex_init(&zdev->fmb_lock); mutex_init(&zdev->kzdev_lock); @@ -816,6 +816,17 @@ error: return ERR_PTR(rc); }
+/** + * zpci_add_device() - Add a previously created zPCI device to the zPCI subsystem + * @zdev: The zPCI device to be added + * + * A struct zpci_dev is added to the zPCI subsystem and to a virtual PCI bus creating + * a new one as necessary. A hotplug slot is created and events start to be handled. + * If successful from this point on zpci_zdev_get() and zpci_zdev_put() must be used. + * If adding the struct zpci_dev fails the device was not added and should be freed. + * + * Return: 0 on success, or an error code otherwise + */ int zpci_add_device(struct zpci_dev *zdev) { int rc; @@ -829,6 +840,7 @@ int zpci_add_device(struct zpci_dev *zde if (rc) goto error_destroy_iommu;
+ kref_init(&zdev->kref); spin_lock(&zpci_list_lock); list_add_tail(&zdev->entry, &zpci_list); spin_unlock(&zpci_list_lock); @@ -1105,7 +1117,8 @@ static void zpci_add_devices(struct list list_sort(NULL, scan_list, &zpci_cmp_rid); list_for_each_entry_safe(zdev, tmp, scan_list, entry) { list_del_init(&zdev->entry); - zpci_add_device(zdev); + if (zpci_add_device(zdev)) + kfree(zdev); } }
--- a/arch/s390/pci/pci_event.c +++ b/arch/s390/pci/pci_event.c @@ -340,7 +340,10 @@ static void __zpci_event_availability(st zdev = zpci_create_device(ccdf->fid, ccdf->fh, ZPCI_FN_STATE_CONFIGURED); if (IS_ERR(zdev)) break; - zpci_add_device(zdev); + if (zpci_add_device(zdev)) { + kfree(zdev); + break; + } } else { /* the configuration request may be stale */ if (zdev->state != ZPCI_FN_STATE_STANDBY) @@ -354,7 +357,10 @@ static void __zpci_event_availability(st zdev = zpci_create_device(ccdf->fid, ccdf->fh, ZPCI_FN_STATE_STANDBY); if (IS_ERR(zdev)) break; - zpci_add_device(zdev); + if (zpci_add_device(zdev)) { + kfree(zdev); + break; + } } else { zpci_update_fh(zdev, ccdf->fh); }