This is a note to let you know that I've just added the patch titled NFC: fix broken device allocation to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: nfc-fix-broken-device-allocation.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 20777bc57c346b6994f465e0d8261a7fbf213a09 Mon Sep 17 00:00:00 2001 From: Johan Hovold <johan@xxxxxxxxxx> Date: Thu, 30 Mar 2017 12:15:35 +0200 Subject: NFC: fix broken device allocation From: Johan Hovold <johan@xxxxxxxxxx> commit 20777bc57c346b6994f465e0d8261a7fbf213a09 upstream. Commit 7eda8b8e9677 ("NFC: Use IDR library to assing NFC devices IDs") moved device-id allocation and struct-device initialisation from nfc_allocate_device() to nfc_register_device(). This broke just about every nfc-device-registration error path, which continue to call nfc_free_device() that tries to put the device reference of the now uninitialised (but zeroed) struct device: kobject: '(null)' (ce316420): is not initialized, yet kobject_put() is being called. The late struct-device initialisation also meant that various work queues whose names are derived from the nfc device name were also misnamed: 421 root 0 SW< [(null)_nci_cmd_] 422 root 0 SW< [(null)_nci_rx_w] 423 root 0 SW< [(null)_nci_tx_w] Move the id-allocation and struct-device initialisation back to nfc_allocate_device() and fix up the single call site which did not use nfc_free_device() in its error path. Fixes: 7eda8b8e9677 ("NFC: Use IDR library to assing NFC devices IDs") Cc: Samuel Ortiz <sameo@xxxxxxxxxxxxxxx> Signed-off-by: Johan Hovold <johan@xxxxxxxxxx> Signed-off-by: Samuel Ortiz <sameo@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/nfc/core.c | 31 ++++++++++++++++++------------- 1 file changed, 18 insertions(+), 13 deletions(-) --- a/net/nfc/core.c +++ b/net/nfc/core.c @@ -950,6 +950,8 @@ static void nfc_release(struct device *d kfree(se); } + ida_simple_remove(&nfc_index_ida, dev->idx); + kfree(dev); } @@ -1024,6 +1026,7 @@ struct nfc_dev *nfc_allocate_device(stru int tx_headroom, int tx_tailroom) { struct nfc_dev *dev; + int rc; if (!ops->start_poll || !ops->stop_poll || !ops->activate_target || !ops->deactivate_target || !ops->im_transceive) @@ -1036,6 +1039,15 @@ struct nfc_dev *nfc_allocate_device(stru if (!dev) return NULL; + rc = ida_simple_get(&nfc_index_ida, 0, 0, GFP_KERNEL); + if (rc < 0) + goto err_free_dev; + dev->idx = rc; + + dev->dev.class = &nfc_class; + dev_set_name(&dev->dev, "nfc%d", dev->idx); + device_initialize(&dev->dev); + dev->ops = ops; dev->supported_protocols = supported_protocols; dev->tx_headroom = tx_headroom; @@ -1058,6 +1070,11 @@ struct nfc_dev *nfc_allocate_device(stru } return dev; + +err_free_dev: + kfree(dev); + + return ERR_PTR(rc); } EXPORT_SYMBOL(nfc_allocate_device); @@ -1072,14 +1089,6 @@ int nfc_register_device(struct nfc_dev * pr_debug("dev_name=%s\n", dev_name(&dev->dev)); - dev->idx = ida_simple_get(&nfc_index_ida, 0, 0, GFP_KERNEL); - if (dev->idx < 0) - return dev->idx; - - dev->dev.class = &nfc_class; - dev_set_name(&dev->dev, "nfc%d", dev->idx); - device_initialize(&dev->dev); - mutex_lock(&nfc_devlist_mutex); nfc_devlist_generation++; rc = device_add(&dev->dev); @@ -1117,12 +1126,10 @@ EXPORT_SYMBOL(nfc_register_device); */ void nfc_unregister_device(struct nfc_dev *dev) { - int rc, id; + int rc; pr_debug("dev_name=%s\n", dev_name(&dev->dev)); - id = dev->idx; - if (dev->rfkill) { rfkill_unregister(dev->rfkill); rfkill_destroy(dev->rfkill); @@ -1147,8 +1154,6 @@ void nfc_unregister_device(struct nfc_de nfc_devlist_generation++; device_del(&dev->dev); mutex_unlock(&nfc_devlist_mutex); - - ida_simple_remove(&nfc_index_ida, id); } EXPORT_SYMBOL(nfc_unregister_device); Patches currently in stable-queue which might be from johan@xxxxxxxxxx are queue-3.18/nfc-fix-broken-device-allocation.patch