Crash in ContactsSynchronizer

Question

Crash in ContactsSynchronizer

or-else opened this issue 5 years ago · comments

This is a fresh installation which has never logged in. It seems to assume that the database has been created.

#5	0x000000010d4a6558 in SubscriberDb.createTable() at /tinode/ios/Tinodios/db/SubscriberDb.swift:68
#6	0x000000010d3f31f5 in BaseDb.initDb() at /tinode/ios/Tinodios/db/BaseDb.swift:82
#7	0x000000010d3f3e8f in static BaseDb.getInstance() at /tinode/ios/Tinodios/db/BaseDb.swift:100
#8	0x000000010d3ee233 in ContactsManager.init() at /tinode/ios/Tinodios/account/ContactsManager.swift:32
#9	0x000000010d3ede30 in ContactsManager.__allocating_init() ()
#10	0x000000010d3edddc in globalinit_33_4AE933758BA578E6197EF98E870A28F2_func0 /tinode/ios/Tinodios/account/ContactsManager.swift:27
#11	0x0000000111b7ddb5 in _dispatch_client_callout ()
#12	0x0000000111b7f83c in _dispatch_once_callout ()
#13	0x00000001111f6579 in swift_once ()
#14	0x000000010d3edeb4 in ContactsManager.default.unsafeMutableAddressor at /tinode/ios/Tinodios/account/ContactsManager.swift:27
#15	0x000000010d3a28f6 in ContactsSynchronizer.synchronizeInternal() at /tinode/ios/Tinodios/account/ContactsSynchronizer.swift:125
#16	0x000000010d39f7ab in closure #1 in ContactsSynchronizer.authStatus.didset at /tinode/ios/Tinodios/account/ContactsSynchronizer.swift:45

Gene · Answer 1 · Mon Aug 05 2019 17:32:29 GMT+0800 (China Standard Time)

Crashes about once in 3 runs.

aforge · Answer 2 · Tue Aug 06 2019 13:45:46 GMT+0800 (China Standard Time)

I can't reproduce this.
Do you have the rest of the stack trace and the error message by any chance?

Gene · Answer 3 · Tue Aug 06 2019 14:48:59 GMT+0800 (China Standard Time)

I cannot reproduce it today. It's been happening regularly yesterday. I'll collect more info if I see it again.

Gene · Answer 4 · Fri Aug 09 2019 22:42:46 GMT+0800 (China Standard Time)

Got it again today. This is the entire call stack. It crashes immediately on startup while logged out.

#0	0x0000000106102b50 in _swift_runtime_on_report ()
#1	0x00000001061624e8 in _swift_stdlib_reportFatalError ()
#2	0x00000001060624d6 in specialized closure #2 in _fatalErrorMessage(_:_:file:line:flags:) ()
#3	0x0000000106062853 in specialized _fatalErrorMessage(_:_:file:line:flags:) ()
#4	0x0000000105e5df83 in _fatalErrorMessage(_:_:file:line:flags:) ()
#5	0x00000001023d2c48 in SubscriberDb.createTable() at /Users/gene/ventures/tinode/ios/Tinodios/db/SubscriberDb.swift:68
#6	0x00000001023214f5 in BaseDb.initDb() at /Users/gene/ventures/tinode/ios/Tinodios/db/BaseDb.swift:82
#7	0x000000010232218f in static BaseDb.getInstance() at /Users/gene/ventures/tinode/ios/Tinodios/db/BaseDb.swift:100
#8	0x000000010231c343 in ContactsManager.init() at /Users/gene/ventures/tinode/ios/Tinodios/account/ContactsManager.swift:32
#9	0x000000010231bf40 in ContactsManager.__allocating_init() ()
#10	0x000000010231beec in globalinit_33_4AE933758BA578E6197EF98E870A28F2_func0 at /Users/gene/ventures/tinode/ios/Tinodios/account/ContactsManager.swift:27
#11	0x0000000106aacdb5 in _dispatch_client_callout ()
#12	0x0000000106aae83c in _dispatch_once_callout ()
#13	0x0000000106125579 in swift_once ()
#14	0x000000010231bfc4 in ContactsManager.default.unsafeMutableAddressor at /Users/gene/ventures/tinode/ios/Tinodios/account/ContactsManager.swift:27
#15	0x00000001022cfcf6 in ContactsSynchronizer.synchronizeInternal() at /Users/gene/ventures/tinode/ios/Tinodios/account/ContactsSynchronizer.swift:125
#16	0x00000001022ccbab in closure #1 in ContactsSynchronizer.authStatus.didset at /Users/gene/ventures/tinode/ios/Tinodios/account/ContactsSynchronizer.swift:45
#17	0x00000001022d411c in partial apply for closure #1 in ContactsSynchronizer.authStatus.didset ()
#18	0x000000010229718d in thunk for @escaping @callee_guaranteed () -> () ()
#19	0x0000000106aabd7f in _dispatch_call_block_and_release ()
#20	0x0000000106aacdb5 in _dispatch_client_callout ()
#21	0x0000000106ab4225 in _dispatch_lane_serial_drain ()
#22	0x0000000106ab4e9c in _dispatch_lane_invoke ()
#23	0x0000000106abeea3 in _dispatch_workloop_worker_thread ()
#24	0x0000000106f5a611 in _pthread_wqthread ()
#25	0x0000000106f5a3fd in start_wqthread ()

let topicDb = BaseDb.getInstance().topicDb! is nil.

Gene · Answer 5 · Fri Aug 09 2019 23:53:28 GMT+0800 (China Standard Time)

I don't see the immediate reason for the crash but there is a logical problem in initialization of ContactsManager:

ContactsManager.init() calls BaseDb.getInstance()
If it's been initialized, it returns BaseDb.default - all is fine.
If it's not yet initialized, it proceeds to initialize it by calling BaseDb.initDb()
BaseDb.initDb() makes calls to self.xxxxDb!.createTable()
And self.xxxxDb!.createTable() calls BaseDb.getInstance() which returns assigned but not fully initialized BaseDb.default!

Gene · Answer 6 · Fri Aug 09 2019 23:56:47 GMT+0800 (China Standard Time)

My guess it's a race condition due to the timing of the run of synchronizeContactsPeriodically: if it happens to be run before DB is initialized by other means the app crashes. Otherwise it's fine.

Gene · Answer 7 · Sat Aug 10 2019 00:15:41 GMT+0800 (China Standard Time)

How about this? 1c68eac

aforge · Answer 8 · Sat Aug 10 2019 12:54:49 GMT+0800 (China Standard Time)

Thanks for discovering this.
I'll also refactor createTable() to not use BaseDb.getInstance().

Gene · Answer 9 · Sat Nov 09 2019 02:55:08 GMT+0800 (China Standard Time)

I think it's fixed. I have not seen these crashes for a long time. I'm closing.