1218830 - SendTo: Crash with unowned profile in BrowserSyncManager.onFinishedSyncing

Status: RESOLVED FIXED

(Firefox for iOS :: General, defect)

Description

[Richard Newman [:rnewman]]

We have an unowned reference to our profile to avoid a retain cycle.

But we use notifications to hear when a sync is finished, and those notifications call:

        @objc func onFinishSyncing(notification: NSNotification) {
            profile.prefs.setTimestamp(NSDate.now(), forKey: PrefsKeys.KeyLastSyncFinishTime)
        }

We have a crash in 1.0.1 that indicates that this notification can be processed after the profile has already been deallocated.

Based on code reading, this bug will affect 1.1.



Thread 7 Crashed:
0   libswiftCore.dylib            	0x00a3b8a0 swift_retainUnowned + 40 (Debug.h:39)
1   SendTo                        	0x000e8f9c @objc SendTo.BrowserProfile.BrowserSyncManager.onFinishSyncing (SendTo.BrowserProfile.BrowserSyncManager)(ObjectiveC.NSNotification) -> () + 48 (<unknown>:0)
2   CoreFoundation                	0x23d5fffc __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__ + 12 (CFNotificationCenter.c:676)
3   CoreFoundation                	0x23d5fa0a _CFXRegistrationPost + 398 (CFNotificationCenter.c:172)
4   CoreFoundation                	0x23d5f7e0 ___CFXNotificationPost_block_invoke + 40 (CFNotificationCenter.c:1017)
5   CoreFoundation                	0x23db3ac2 -[_CFXNotificationRegistrar find:object:observer:enumerator:] + 1334 (CFXNotificationRegistrar.m:164)
6   CoreFoundation                	0x23cc104a _CFXNotificationPost + 486 (CFNotificationCenter.c:1037)
7   SendTo                        	0x00107680 SendTo.BrowserProfile.BrowserSyncManager.((withSyncInputs in _8B55E06CDD7E68DC6BC252D6F91FAD70) (SendTo.BrowserProfile.BrowserSyncManager) -> <A>(label : Swift.String?, function : (Sync.SyncDelegate, Shared.Prefs, Sync.Ready) -> Shared.Deferred<Shared.Result<A>>) -> Shared.Deferred<Shared.Result<A>>?).(closure #2) + 360 (Profile.swift:604)
8   Shared                        	0x006bd560 reabstraction thunk helper <T_0_0> from @callee_owned (@in T_0_0) -> (@unowned ()) to @callee_owned (@in T_0_0) -> (@out ()) + 32 (<unknown>:0)
9   Shared                        	0x006b78a4 partial apply forwarder for reabstraction thunk helper <T_0_0> from @callee_owned (@in T_0_0) -> (@unowned ()) to @callee_owned (@in T_0_0) -> (@out ()) with unmangled suffix "249 + 100 (<unknown>:0)
10  Shared                        	0x006be138 reabstraction thunk helper <T_0_0> from @callee_owned (@in T_0_0) -> (@out ()) to @callee_owned (@in T_0_0) -> (@unowned ()) + 44 (<unknown>:0)
11  Shared                        	0x006c4f20 0x660000 + 413472
12  Shared                        	0x006b74a8 partial apply forwarder for Shared.Deferred.((_fill in _64863D17A065AD747F9AFBDCF9C2ED6A) <A>(Shared.Deferred<A>) -> (A, assertIfFilled : Swift.Bool) -> ()).(closure #2) + 120 (<unknown>:0)
13  Shared                        	0x006b9340 reabstraction thunk helper from @callee_owned () -> (@unowned ()) to @callee_unowned @objc_block () -> (@unowned ()) + 56 (<unknown>:0)
14  libdispatch.dylib             	0x35baced6 _dispatch_call_block_and_release + 10 (init.c:761)
15  libdispatch.dylib             	0x35bb8870 _dispatch_root_queue_drain + 1572 (inline_internal.h:1063)
16  libdispatch.dylib             	0x35bb824a _dispatch_worker_thread3 + 94 (queue.c:4250)
17  libsystem_pthread.dylib       	0x35d41e28 _pthread_wqthread + 1024 (pthread.c:1990)
18  libsystem_pthread.dylib       	0x35d41a18 start_wqthread + 8 (pthread_asm.s:151)

Comment 1

[Richard Newman [:rnewman]]

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