CODEWITHSUNDEEP
iosios6nsurlcache
Ben-G
Ben-G

Reputation: 5026

NSURLCache crashes under iOS 6.1

Using iOS 6.1 my App crashes regulary, directly after startup, when it attempts to make several HTTP-Requests, but it works fine on any OS < 6.1.

I'm experiencing EXC_BAD_ACCESS crashes in the strlen function called from the Queue : com.apple.CFURLCACHE_work_queue, everytime my App is started, except for the first time.

NSURLCache crashes

I could resolve the issue by clearing the NSURLCache, directly after the app started:

[[NSURLCache sharedURLCache] removeAllCachedResponses];

Does anyone else experience these crashes? Could there be some issue in the application code causing these crashes? Or should this be a bug filed to apple?

Upvotes: 4

Views: 2686

Answers (2)

Luke Redpath
Luke Redpath

Reputation: 10555

This is only half an answer, but I'm running into a very similar problem whilst running my unit tests. Bizarrely, this only seemed to start happening today.

The full details of my issue are outlined in this Apple dev forums thread.

The common link between our problems appears to be the call to RecreateEmptyPersistentStoreOnDiskAndOpen_NoLock(). If my understanding of CFURLCache is correct, and based on the backtrace, it uses a sqlite3 database internally as a cache. I'd assume this function call creates the empty sqlite3 database on disk.

I was able to repeatedly and consistently stop my tests crashing by deleting the simulator's Library/Caches directory (~/Library/Application Support/iPhone Simulator/6.1/Library/Caches) and make the crash return by re-creating that directory.

Deleting the entire simulator home directory and letting it be recreated by launching my app in the simulator would also fix and re-create the issue.

I'm guessing this is an OS bug; the curious thing is why for me, it only just started happening.

Upvotes: 1

slammens
slammens

Reputation: 11

Experiencing a similar crash since iOS 6.1 with a newly installed application. The difference is that the crash occurs when tapping a text cell in a table view. No web requests are being made at this time.

This is the bt:

thread #4: tid = 0x2903, 0x3ae7ad74 libsystem_c.dylib`strlen + 28, stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
frame #0: 0x3ae7ad74 libsystem_c.dylib`strlen + 28
frame #1: 0x3ac6be24 libsqlite3.dylib`___lldb_unnamed_function282$$libsqlite3.dylib + 1232
frame #2: 0x3ac74a5e libsqlite3.dylib`sqlite3_file_control + 174
frame #3: 0x328493fe CFNetwork`__CFURLCache::RecreateEmptyPersistentStoreOnDiskAndOpen_NoLock() + 30
frame #4: 0x32849000 CFNetwork`__CFURLCache::RecreateEmptyPersistentStoreOnDiskAndOpen() + 44
frame #5: 0x327f9488 CFNetwork`__CFURLCache::OpenDatabase() + 192
frame #6: 0x32846a72 CFNetwork`__CFURLCache::ProcessCacheTasks0(bool) + 358
frame #7: 0x32846900 CFNetwork`__CFURLCache::ProcessCacheTasks(bool) + 36
frame #8: 0x3284681e CFNetwork`__CFURLCache::_CFURLCacheTimerCallback0() + 358
frame #9: 0x328466ac CFNetwork`__CFURLCache::_CFURLCacheTimerCallback(void*) + 32
frame #10: 0x328490fc CFNetwork`__SignalWorkerTaskToPerformWork_block_invoke_0 + 12
frame #11: 0x3ae4611e libdispatch.dylib`_dispatch_call_block_and_release + 10
frame #12: 0x3ae49ece libdispatch.dylib`_dispatch_queue_drain$VARIANT$mp + 142
frame #13: 0x3ae49dc0 libdispatch.dylib`_dispatch_queue_invoke$VARIANT$mp + 40
frame #14: 0x3ae4a91c libdispatch.dylib`_dispatch_root_queue_drain + 184
frame #15: 0x3ae4aac0 libdispatch.dylib`_dispatch_worker_thread2 + 84
frame #16: 0x3ae7aa10 libsystem_c.dylib`_pthread_wqthread + 360
frame #17: 0x3ae7a8a4 libsystem_c.dylib`start_wqthread + 8

Reported this as a TSI to Apple, it was reviewed and they requests that I log this as a bug, still need to do this.

Interestingly enough the solution which you found also helped me, clearing the cache at launch solved this problem.

Upvotes: 1

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