Recurring crash when connection object goes out of scope

[ssokol]

SQLite.swift Version: 0.15.3
X-Code: 15.4
iOS: 17.5.1 on iPad Pro 11-inch (M4)
Included via SPM

I recently started getting crash reports from Crashlytics indicating an issue with the release of a SQLite connection object in a specific module within my app.

The code is extremely simple - it opens a connection to the SQLite file, runs a single query, then exits, allowing the connection object to fall out of scope. Here's the function where it occurs:

    private func findObstaclesWithinBox(bbox:GLMapBBox, minElevation: Int = 0) -> [FBObstacle] {
        
        print("Finding obstacles within box...")
        
        let minX = bbox.origin.x
        let minY = bbox.origin.y
        let maxX = bbox.origin.x + bbox.size.x
        let maxY = bbox.origin.y + bbox.size.y
        
        let mpMin = GLMapPoint(x: minX, y: minY)
        let mpMax = GLMapPoint(x: maxX, y: maxY)
        let gpMin = GLMapView.makeGeoPoint(from: mpMin)
        let gpMax = GLMapView.makeGeoPoint(from: mpMax)
        
        let query = obstacleTable.select(identifier, type, agl, msl, lighting, lat, lng)
            .filter(lat >= (gpMin.lat - 0.1))
            .filter(lng >= (gpMin.lon - 0.1))
            .filter(lat <= (gpMax.lat + 0.1))
            .filter(lng <= (gpMax.lon + 0.1))
            .filter(msl >= minElevation)
            .filter(agl > 150)
        
        var obstacles:[FBObstacle] = []
        if let db = FBDatabaseManager.shared.getDatabaseConnection() {
            do {
                let q = try db.prepare(query)
                for row in q {
                    if let obs = makeObstacleFromRow(row: row) {
                        obstacles.append(obs)
                    }
                }
            } catch {
                print("Something went wrong querying obstacles")
            }
        } // CRASH OCCURS HERE
        return obstacles
    }

This function is executed thousands of times over the life of a typical app instance. It crashes once every one to two, always in the same place. There's nothing unusual about the means by which the database handle is allocated: other elements of the application use the same singleton database manager instance to return a handle without any problem.

I finally managed to catch the crash in the debugger on a test system with Address Sanitizer enabled. Here are a screenshot and a copy of the output from X-Code. Please let me know if you see anything that I'm missing or have any idea what might be causing this.

X-Code Screenshot

X-Code Crash Log

2024-08-14 15:14:00.139 -0500: Finding obstacles within box...
=================================================================
==3269==ERROR: AddressSanitizer: attempting free on address which was not malloc()-ed: 0x00013e2a0aa0 in thread T1116
2024-08-14 15:14:00.180 -0500: FDC: 2024-08-14 21:14:00.0981 | fvTraffic        | Deleting distant target: N400FJ (83.2)
2024-08-14 15:14:00.181 -0500: FDC: 2024-08-14 21:14:00.0991 | fvTraffic        | Deleting distant target: N352I9 (64.5)
2024-08-14 15:14:00.181 -0500: FDC: 2024-08-14 21:14:00.0996 | fvTraffic        | Deleting distant target: N300ML (52.9)
2024-08-14 15:14:00.183 -0500: FDC: 2024-08-14 21:14:00.1008 | fvTraffic        | Deleting distant target: N455UY (54.1)
2024-08-14 15:14:00.184 -0500: FDC: 2024-08-14 21:14:00.1029 | fvTraffic        | Deleting distant target: N483O1 (60.6)
2024-08-14 15:14:00.186 -0500: FDC: 2024-08-14 21:14:00.1039 | fvTraffic        | Deleting distant target: N125E9 (46.2)
    #0 0x106d40558 in __sanitizer_mz_free+0xf8 (/private/var/containers/Bundle/Application/2A2E4E89-4163-4145-948C-DCB323F9A064/FlightBox PFD.app/Frameworks/libclang_rt.asan_ios_dynamic.dylib:arm64e+0x54558)
    #1 0x1ce4a8780 in sqlite3_log+0x11c0c (/usr/lib/libsqlite3.dylib:arm64e+0x2b780)
    #2 0x1ce4a85ac in sqlite3_log+0x11a38 (/usr/lib/libsqlite3.dylib:arm64e+0x2b5ac)
    #3 0x1ce52f6b8 in sqlite3_sourceid+0x21608 (/usr/lib/libsqlite3.dylib:arm64e+0xb26b8)
    #4 0x1ce524870 in sqlite3_sourceid+0x167c0 (/usr/lib/libsqlite3.dylib:arm64e+0xa7870)
    #5 0x1ce4cece8 in sqlite3_bind_int64+0xee0 (/usr/lib/libsqlite3.dylib:arm64e+0x51ce8)
    #6 0x1ce4f1070 in sqlite3_backup_finish+0x2d4 (/usr/lib/libsqlite3.dylib:arm64e+0x74070)
    #7 0x1ce4fb9c4 in sqlite3_txn_state+0x4f4 (/usr/lib/libsqlite3.dylib:arm64e+0x7e9c4)
    #8 0x1042f3c14 in SQLite.Connection.deinit+0x160 (/private/var/containers/Bundle/Application/2A2E4E89-4163-4145-948C-DCB323F9A064/FlightBox PFD.app/FlightBox PFD:arm64+0x101e37c14)
    #9 0x1042f3e80 in SQLite.Connection.__deallocating_deinit+0x15c (/private/var/containers/Bundle/Application/2A2E4E89-4163-4145-948C-DCB323F9A064/FlightBox PFD.app/FlightBox PFD:arm64+0x101e37e80)
    #10 0x1a3297368 in <redacted>+0x34 (/usr/lib/swift/libswiftCore.dylib:arm64e+0x3ab368)
    #11 0x1a3298484 in <redacted>+0x84 (/usr/lib/swift/libswiftCore.dylib:arm64e+0x3ac484)
    #12 0x10266b45c in FlightBox_PFD.FBObstacleFactory.(findObstaclesWithinBox in _B4968670F7213BBAF4E566B92458E66A)(bbox: __C.GLMapBBox, minElevation: Swift.Int) -> Swift.Array<FlightBox_PFD.FBObstacle>+0x9a0c (/private/var/containers/Bundle/Application/2A2E4E89-4163-4145-948C-DCB323F9A064/FlightBox PFD.app/FlightBox PFD:arm64+0x1001af45c)
    #13 0x10265f3f4 in FlightBox_PFD.FBObstacleFactory.displayObstaclesWithinBBox(altitude: Swift.Double) -> ()+0x1a4c (/private/var/containers/Bundle/Application/2A2E4E89-4163-4145-948C-DCB323F9A064/FlightBox PFD.app/FlightBox PFD:arm64+0x1001a33f4)
    #14 0x102647040 in closure #1 @Sendable () -> () in FlightBox_PFD.FBObstacleFactory.locationUpdate(notification: Foundation.Notification) -> ()+0x2a4 (/private/var/containers/Bundle/Application/2A2E4E89-4163-4145-948C-DCB323F9A064/FlightBox PFD.app/FlightBox PFD:arm64+0x10018b040)
    #15 0x102582840 in reabstraction thunk helper from @escaping @callee_guaranteed @Sendable () -> () to @escaping @callee_unowned @convention(block) @Sendable () -> ()+0xa4 (/private/var/containers/Bundle/Application/2A2E4E89-4163-4145-948C-DCB323F9A064/FlightBox PFD.app/FlightBox PFD:arm64+0x1000c6840)
    #16 0x106d3e5bc in __wrap_dispatch_async_block_invoke+0xc0 (/private/var/containers/Bundle/Application/2A2E4E89-4163-4145-948C-DCB323F9A064/FlightBox PFD.app/Frameworks/libclang_rt.asan_ios_dynamic.dylib:arm64e+0x525bc)
    #17 0x1091c0b94 in _dispatch_call_block_and_release+0x1c (/usr/lib/system/introspection/libdispatch.dylib:arm64e+0x4b94)

    #18 0x1091c27b8 in _dispatch_client_callout+0x10 (/usr/lib/system/introspection/libdispatch.dylib:arm64e+0x67b8)
    #19 0x1091ca668 in _dispatch_lane_serial_drain+0x33c (/usr/lib/system/introspection/libdispatch.dylib:arm64e+0xe668)
    #20 0x1091cb404 in _dispatch_lane_invoke+0x194 (/usr/lib/system/introspection/libdispatch.dylib:arm64e+0xf404)
    #21 0x1091d8400 in _dispatch_root_queue_drain_deferred_wlh+0x144 (/usr/lib/system/introspection/libdispatch.dylib:arm64e+0x1c400)
    #22 0x1091d7a34 in _dispatch_workloop_worker_thread+0x1b8 (/usr/lib/system/introspection/libdispatch.dylib:arm64e+0x1ba34)
    #23 0x2013fa930 in _pthread_wqthread+0x11c (/usr/lib/system/libsystem_pthread.dylib:arm64e+0x4930)
    #24 0x2013f70c8 in start_wqthread+0x4 (/usr/lib/system/libsystem_pthread.dylib:arm64e+0x10c8)

0x00013e2a0aa0 is located 240 bytes after 32-byte region [0x00013e2a0990,0x00013e2a09b0)
allocated by thread T0 here:
2024-08-14 15:14:00.187 -0500: FDC: 2024-08-14 21:14:00.1058 | fvTraffic        | Deleting distant target: N064DY (69.0)
2024-08-14 15:14:00.188 -0500: FDC: 2024-08-14 21:14:00.1066 | fvTraffic        | Deleting distant target: N4153V (84.1)
2024-08-14 15:14:00.189 -0500: FDC: 2024-08-14 21:14:00.1074 | fvTraffic        | Deleting distant target: N113V8 (59.6)
2024-08-14 15:14:00.189 -0500: FDC: 2024-08-14 21:14:00.1079 | fvTraffic        | Deleting distant target: N316EA (70.4)
2024-08-14 15:14:00.190 -0500: FDC: 2024-08-14 21:14:00.1089 | fvTraffic        | Deleting distant target: N86698 (30.9)
    #0 0x106d3fba0 in wrap_calloc+0x9c (/private/var/containers/Bundle/Application/2A2E4E89-4163-4145-948C-DCB323F9A064/FlightBox PFD.app/Frameworks/libclang_rt.asan_ios_dynamic.dylib:arm64e+0x53ba0)
    #1 0x1b47f6c80 in <redacted>+0x64 (/usr/lib/system/libsystem_malloc.dylib:arm64e+0x1bc80)
    #2 0x19c51dae4 in <redacted>+0x90 (/usr/lib/libobjc.A.dylib:arm64e+0xdae4)
    #3 0x19c51dd64 in <redacted>+0x310 (/usr/lib/libobjc.A.dylib:arm64e+0xdd64)
    #4 0x19c51cfac in <redacted>+0x190 (/usr/lib/libobjc.A.dylib:arm64e+0xcfac)
    #5 0x19c515144 in <redacted>+0x36c (/usr/lib/libobjc.A.dylib:arm64e+0x5144)
    #6 0x19c5134c0 in <redacted>+0x40 (/usr/lib/libobjc.A.dylib:arm64e+0x34c0)
    #7 0x1af9ea1c8 in <redacted>+0x98 (/System/Library/PrivateFrameworks/UIFoundation.framework/UIFoundation:arm64e+0x411c8)
    #8 0x1af9e9090 in <redacted>+0x68 (/System/Library/PrivateFrameworks/UIFoundation.framework/UIFoundation:arm64e+0x40090)
    #9 0x1af9e7f90 in <redacted>+0x6a0 (/System/Library/PrivateFrameworks/UIFoundation.framework/UIFoundation:arm64e+0x3ef90)
    #10 0x1af9f5cdc in <redacted>+0x94 (/System/Library/PrivateFrameworks/UIFoundation.framework/UIFoundation:arm64e+0x4ccdc)
    #11 0x1af9f7e5c in <redacted>+0x734 (/System/Library/PrivateFrameworks/UIFoundation.framework/UIFoundation:arm64e+0x4ee5c)
    #12 0x1af9f76f8 in <redacted>+0xcc (/System/Library/PrivateFrameworks/UIFoundation.framework/UIFoundation:arm64e+0x4e6f8)
    #13 0x1af9f6614 in <redacted>+0x1dc (/System/Library/PrivateFrameworks/UIFoundation.framework/UIFoundation:arm64e+0x4d614)
    #14 0x1af9d669c in <redacted>+0x43c (/System/Library/PrivateFrameworks/UIFoundation.framework/UIFoundation:arm64e+0x2d69c)
    #15 0x1af9f7334 in <redacted>+0xb4 (/System/Library/PrivateFrameworks/UIFoundation.framework/UIFoundation:arm64e+0x4e334)
    #16 0x1af9d9f00 in <redacted>+0x3e8 (/System/Library/PrivateFrameworks/UIFoundation.framework/UIFoundation:arm64e+0x30f00)
    #17 0x1afa087a8 in <redacted>+0x12c (/System/Library/PrivateFrameworks/UIFoundation.framework/UIFoundation:arm64e+0x5f7a8)
    #18 0x1afa5de08 in <redacted>+0x28 (/System/Library/PrivateFrameworks/UIFoundation.framework/UIFoundation:arm64e+0xb4e08)
    #19 0x1afa5b028 in <redacted>+0x454 (/System/Library/PrivateFrameworks/UIFoundation.framework/UIFoundation:arm64e+0xb2028)
    #20 0x1afa5dcf0 in <redacted>+0xb0 (/System/Library/PrivateFrameworks/UIFoundation.framework/UIFoundation:arm64e+0xb4cf0)
    #21 0x1af9b4aac in <redacted>+0xa28 (/System/Library/PrivateFrameworks/UIFoundation.framework/UIFoundation:arm64e+0xbaac)
    #22 0x1af9b3c5c in <redacted>+0x280 (/System/Library/PrivateFrameworks/UIFoundation.framework/UIFoundation:arm64e+0xac5c)
    #23 0x1a6938e14 in <redacted>+0x6c (/System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore:arm64e+0xf2e14)
    #24 0x1a6935ab8 in <redacted>+0x1d4 (/System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore:arm64e+0xefab8)
    #25 0x1a690c5f0 in <redacted>+0x1bc (/System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore:arm64e+0xc65f0)
    #26 0x1a6915ecc in <redacted>+0x1b4 (/System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore:arm64e+0xcfecc)
    #27 0x1a6915be0 in <redacted>+0x18 (/System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore:arm64e+0xcfbe0)
    #28 0x1a6916290 in <redacted>+0x4c (/System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore:arm64e+0xd0290)
    #29 0x1041f173c in FlightBox_PFD.MFDViewController.(heightForView in _2E534678638008F374288BF91470636D)(text: __C.NSAttributedString) -> CoreGraphics.CGFloat+0x6c4 (/private/var/containers/Bundle/Application/2A2E4E89-4163-4145-948C-DCB323F9A064/FlightBox PFD.app/FlightBox PFD:arm64+0x101d3573c)

Thread T1116 created by T1115 here:
    <empty stack>

Thread T1115 created by T9 here:
    <empty stack>

Thread T9 created by T4 here:
    <empty stack>

Thread T4 created by T2 here:
    <empty stack>

Thread T2 created by T0 here:
    <empty stack>

SUMMARY: AddressSanitizer: bad-free (/private/var/containers/Bundle/Application/2A2E4E89-4163-4145-948C-DCB323F9A064/FlightBox PFD.app/Frameworks/libclang_rt.asan_ios_dynamic.dylib:arm64e+0x54558) in __sanitizer_mz_free+0xf8
==3269==ABORTING