NFC: Fix sleeping in invalid context when netlink socket is closed
netlink_register_notifier requires notify functions to not sleep. nfc_stop_poll locks device mutex and must not be called from notifier. Create workqueue that will handle this for all devices. BUG: sleeping function called from invalid context at kernel/mutex.c:269 in_atomic(): 0, irqs_disabled(): 0, pid: 4497, name: neard 1 lock held by neard/4497: Pid: 4497, comm: neard Not tainted 3.5.0-999-nfc+ #5 Call Trace: [<ffffffff810952c5>] __might_sleep+0x145/0x200 [<ffffffff81743dde>] mutex_lock_nested+0x2e/0x50 [<ffffffff816ffd19>] nfc_stop_poll+0x39/0xb0 [<ffffffff81700a17>] nfc_genl_rcv_nl_event+0x77/0xc0 [<ffffffff8174aa8c>] notifier_call_chain+0x5c/0x120 [<ffffffff8174abd6>] __atomic_notifier_call_chain+0x86/0x140 [<ffffffff8174ab50>] ? notifier_call_chain+0x120/0x120 [<ffffffff815e1347>] ? skb_dequeue+0x67/0x90 [<ffffffff8174aca6>] atomic_notifier_call_chain+0x16/0x20 [<ffffffff8162119a>] netlink_release+0x24a/0x280 [<ffffffff815d7aa8>] sock_release+0x28/0xa0 [<ffffffff815d7be7>] sock_close+0x17/0x30 [<ffffffff811b2a7c>] __fput+0xcc/0x250 [<ffffffff811b2c0e>] ____fput+0xe/0x10 [<ffffffff81085009>] task_work_run+0x69/0x90 [<ffffffff8101b951>] do_notify_resume+0x81/0xd0 [<ffffffff8174ef22>] int_signal+0x12/0x17 Signed-off-by: Szymon Janc <szymon.janc@tieto.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
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@ -761,31 +761,63 @@ static struct genl_ops nfc_genl_ops[] = {
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},
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};
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struct urelease_work {
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struct work_struct w;
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int pid;
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};
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static void nfc_urelease_event_work(struct work_struct *work)
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{
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struct urelease_work *w = container_of(work, struct urelease_work, w);
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struct class_dev_iter iter;
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struct nfc_dev *dev;
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pr_debug("pid %d\n", w->pid);
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mutex_lock(&nfc_devlist_mutex);
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nfc_device_iter_init(&iter);
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dev = nfc_device_iter_next(&iter);
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while (dev) {
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mutex_lock(&dev->genl_data.genl_data_mutex);
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if (dev->genl_data.poll_req_pid == w->pid) {
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nfc_stop_poll(dev);
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dev->genl_data.poll_req_pid = 0;
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}
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mutex_unlock(&dev->genl_data.genl_data_mutex);
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dev = nfc_device_iter_next(&iter);
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}
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nfc_device_iter_exit(&iter);
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mutex_unlock(&nfc_devlist_mutex);
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kfree(w);
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}
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static int nfc_genl_rcv_nl_event(struct notifier_block *this,
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unsigned long event, void *ptr)
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{
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struct netlink_notify *n = ptr;
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struct class_dev_iter iter;
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struct nfc_dev *dev;
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struct urelease_work *w;
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if (event != NETLINK_URELEASE || n->protocol != NETLINK_GENERIC)
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goto out;
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pr_debug("NETLINK_URELEASE event from id %d\n", n->pid);
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nfc_device_iter_init(&iter);
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dev = nfc_device_iter_next(&iter);
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while (dev) {
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if (dev->genl_data.poll_req_pid == n->pid) {
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nfc_stop_poll(dev);
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dev->genl_data.poll_req_pid = 0;
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}
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dev = nfc_device_iter_next(&iter);
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w = kmalloc(sizeof(*w), GFP_ATOMIC);
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if (w) {
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INIT_WORK((struct work_struct *) w, nfc_urelease_event_work);
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w->pid = n->pid;
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schedule_work((struct work_struct *) w);
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}
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nfc_device_iter_exit(&iter);
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out:
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return NOTIFY_DONE;
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}
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