• Open Menu Close Menu
  • Apple
  • Shopping Bag
  • Apple
  • Mac
  • iPad
  • iPhone
  • Watch
  • TV
  • Music
  • Support
  • Search apple.com
  • Shopping Bag

Lists

Open Menu Close Menu
  • Terms and Conditions
  • Lists hosted on this site
  • Email the Postmaster
  • Tips for posting to public mailing lists
Re: Crash encountered when calling resume and cancel on a NSURLSessionTask quickly
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Crash encountered when calling resume and cancel on a NSURLSessionTask quickly

  • Subject: Re: Crash encountered when calling resume and cancel on a NSURLSessionTask quickly
  • From: Scott Hancher <email@hidden>
  • Date: Mon, 06 Oct 2014 14:25:55 -0700
We found a short and simple piece of code that triggers our crash.

while (YES) {
    NSURL *url = "" URLWithString:@"http://example.com/bozo"];
    NSURLSessionConfiguration *config = [NSURLSessionConfiguration ephemeralSessionConfiguration];
    NSURLSession *session = [NSURLSession sessionWithConfiguration:config];
    NSURLSessionDataTask *task =
        [session dataTaskWithURL:url
               completionHandler: ^(NSData *data,
                                    NSURLResponse *response,
                                    NSError *error) {
               }];
    [task resume];
    [task cancel];
    // *** It is this call to finishTasksAndInvalidate that seems to trigger the crash.
    // If I comment it out, no crash.
    [session finishTasksAndInvalidate];
  }

Is there something wrong with calling cancel on a task followed by calling finishTasksAndInvalidate on the session that created it? After calling cancel, we're just trying to correctly cleanup the session, but perhaps we should do nothing.

Please advise. Thank you,
++Scott.


On Mon, Oct 6, 2014 at 12:52 PM, Scott Hancher <email@hidden> wrote:
This is occurring in our Google Play Music app.

We've filed radar 18471901. We believe this to be an SDK issue, but would appreciate some guidance if felt otherwise. We've included a test case in the bug.

If we don't bother canceling the download, we avoid the crash, but we don't feel this is a reasonable solution given the unnecessary bandwidth being used, since the user is driving the request to cancel the download.

Here's a sample stack crawl:

Thread 10 CRASHED [EXC_BAD_ACCESS / KERN_INVALID_ADDRESS @ 0x00000000]
0x2bc04fe8	[CFNetwork + 0x0002dfe8 ]	-[__NSURLSessionLocal _createXURLCache]
0x2bc76b0d	[CFNetwork + 0x0009fb0d ]	HTTPProtocol::initialize(NSURLSessionTask const*, URLProtocolClient*)
0x2bc76b0d	[CFNetwork + 0x0009fb0d ]	HTTPProtocol::initialize(NSURLSessionTask const*, URLProtocolClient*)
0x2bc76731	[CFNetwork + 0x0009f731 ]	HTTPProtocol::_instantiateProtocol(__CFAllocator const*, NSURLSessionTask const*, URLProtocolClient*, void const*)
0x2bc05ca3	[CFNetwork + 0x0002eca3 ]	-[__NSURLSessionLocal _newURLProtocolForTask:client:protocolClass:]
0x2bc05da9	[CFNetwork + 0x0002eda9 ]	-[__NSURLSessionLocal _newURLProtocolForTask:client:]
0x2bc9ce0f	[CFNetwork + 0x000c5e0f ]	URLConnectionLoader::ensureLoaderHasProtocolNoLock(NSURLRequest const*)
0x2bc9ddf7	[CFNetwork + 0x000c6df7 ]	URLConnectionLoader::_private_ScheduleOriginLoad(NSURLRequest const*, _CFCachedURLResponse const*)
0x2bc9db65	[CFNetwork + 0x000c6b65 ]	URLConnectionLoader::loadWithWhatToDo(NSURLRequest const*, _CFCachedURLResponse const*, long, URLConnectionLoader::WhatToDo)
0x2bc9d847	[CFNetwork + 0x000c6847 ]	URLConnectionLoader::loadWithCacheValidity(NSURLRequest const*, _CFCachedURLResponse const*, CacheResponseValidity)
0x2bc9dc33	[CFNetwork + 0x000c6c33 ]	___ZN19URLConnectionLoader22_loaderEvent_StartLoadEPK16NSURLSessionTask_block_invoke_2
0x2bc94ca7	[CFNetwork + 0x000bdca7 ]	___ZNK25URLConnectionInstanceData18withWorkQueueAsyncEU13block_pointerFvvE_block_invoke
0x39dbb8c9	[libdispatch.dylib + 0x000018c9 ]	_dispatch_call_block_and_release
0x39dc364f	[libdispatch.dylib + 0x0000964f ]	_dispatch_queue_drain
0x39dbe09b	[libdispatch.dylib + 0x0000409b ]	_dispatch_queue_invoke
0x39dc4b9f	[libdispatch.dylib + 0x0000ab9f ]	_dispatch_root_queue_drain
0x39dc5cd5	[libdispatch.dylib + 0x0000bcd5 ]	_dispatch_worker_thread3
0x39f1ce2f	[libsystem_pthread.dylib + 0x00000e2f ]	_pthread_wqthread
0x39f1cb82	[libsystem_pthread.dylib + 0x00000b82 ]	start_wqthread

Scott.


 _______________________________________________
Do not post admin requests to the list. They will be ignored.
Macnetworkprog mailing list      (email@hidden)
Help/Unsubscribe/Update your Subscription:

This email sent to email@hidden
References: 
 >Crash encountered when calling resume and cancel on a NSURLSessionTask quickly (From: Scott Hancher <email@hidden>)

  • Prev by Date: Crash encountered when calling resume and cancel on a NSURLSessionTask quickly
  • Next by Date: iOS server and client trusts
  • Previous by thread: Crash encountered when calling resume and cancel on a NSURLSessionTask quickly
  • Next by thread: iOS server and client trusts
  • Index(es):
    • Date
    • Thread