iOS app crashes, xcode says 'Lost connection to X's iPhone' when debugging

Question

My app crashes and I need some advice to find and fix the problem. It is not a device or cable problem because it happens with all devices and not only when debugging. Xcode won't stop on an exception breakpoint the app just simply stops running with no error information. When debugging xcode only says 'Lost connection to X's iPhone'. I have the following log from the device, see MY_CRASHING_APP:

Incident Identifier: 85730E97-BA21-4C72-8AD1-02075A8FD9A7
CrashReporter Key:   d9e9eb14ac1801fea11e662a394244d7caf29154
Hardware Model:      iPhone4,1
OS Version:          iPhone OS 8.0 (12A365)
Kernel Version:      Darwin Kernel Version 14.0.0: Tue Aug 19 15:08:02 PDT 2014; root:xnu-2783.1.72~8/RELEASE_ARM_S5L8940X
Date:                2014-09-24 15:02:41 +0200
Time since snapshot: 325 ms

Free pages:                              20793
Active pages:                            20412
Inactive pages:                          10678
Speculative pages:                       1757
Throttled pages:                         55906
Purgeable pages:                         699
Wired pages:                             21196
File-backed pages:                       30263
Anonymous pages:                         2584
Compressions:                            76385
Decompressions:                          3948
Compressor Size:                         81
Uncompressed Pages in Compressor:        61
Page Size:                               4096
Largest process:   MY_CRASHING_APP

Processes
     Name       |            <UUID>                |     CPU Time|     rpages|       purgeable| recent_max| lifetime_max| fds |  [reason]         | (state)

       coreduetd <675ac3d39b193f9bba42896818431859>         0.049         124                0           -           391   50     [vnode-limit]     (daemon) (idle)
           homed <77bcbc47e2723e269b0ff9d115658259>         0.052         146                0           -           458   50     [vnode-limit]     (daemon) (idle)
           gamed <a51b1ad16b693a75aeaaf2166e7b1b0b>         0.049          38                0           -            74   50     [vnode-limit]     (daemon) (idle)
             lsd <72b4494834d3357bb8aa32fd5b5c8e83>         0.068         161                0           -           368   50     [vnode-limit]     (daemon)
   InCallService <88e149874b1c35f2b8adbeee958d7258>        18.461        1289                0           -          3238   50     [vnode-limit]     (resume) (continuous)
 MY_CRASHING_APP <1542054cd5393df29827ca1a6bd34e04>        59.116       24504              600           -         29490 1600     [vnode-limit]     (frontmost) (resume)
            ptpd <c0bc1e573edb3bcebea0f3140a139421>         3.442         878                0           -          1634   50                       (daemon)
        BTServer <1b7372b3ae393847b1c3ccaa720e991e>         3.057         393                0           -          1437   50                       (daemon)
       lockdownd <bb602fb4b5ac3b51af2d22c4fdce9778>        11.306         271                0           -           761   50                       (daemon)
         imagent <01ebc2c08d7f36059714967efaa86e78>        19.892         585                0           -          1286   50                       (daemon)
       locationd <9727e24fbe4f357cb27d7bc8cf882c93>       489.694        1665                0           -          3586   50                       (daemon)
identityservices <13c2b979d6433252a011087be05e1aa5>        22.999         696                0          +2          1585   50                       (daemon)
      discoveryd <dff5d0d2edf43b45b0c7fbd4a3e1b677>        93.758         589                0           -          1077  100                       (daemon)
           wifid <5fb79228aa653a9bb725217b9cb891e6>        63.420         571                0           -          1098   50                       (daemon)
   iaptransportd <ae70565455de38f3aab8993e9d109207>         7.713         306                0           -           579   50                       (daemon)
    mediaserverd <b5ba58774a853d43a17559ae76a6f918>       649.476        1025               64           -          6134   50                       (daemon)
         syslogd <a5a138dc01cd34d19bbe336c03099ce7>        40.100         201                0           -           384   50                       (daemon)
          powerd <b3163caaebd53f7aa42634836472ea04>        43.199         231                0           -           474   50                       (daemon)
            apsd <17af2320ccfb3e668b6455b95b4612ce>        37.461         631                0           -          1445   50                       (daemon)
        networkd <a657abe0ce803333b886876a8f7a36e0>        77.271         596                0           -          1297   50                       (daemon)
     dataaccessd <db655c44d5c830dc9e5f34f7edcb17a4>       243.259        1777                0           -          3097  100                       (daemon)
             vmd <88cebb23d0f1344db23e1896b1787f2d>         0.505         204                0           -           617   50                       (daemon)
            iapd <e84bb9b7cf7530babc36c6ca37b7f345>        11.963         453                0           -          1673   50                       (daemon)
    syslog_relay <9e18dbcbcc07374e9d14c732b8dabad2>         1.424          98                0           -           189   50                       (daemon)
          voiced <2d24fa3e32533f2f8298743eaf348d63>         0.179         210                0           -           581   50                       (daemon)
    itunesstored <d50d5b1c3f693694a2eee878aae8facf>         0.573         908                0           -          1759   50                       (daemon)
     SpringBoard <3e0aacaca7103aa09a71e5c9fee3e012>       841.081        7088               29           -         16912   50                      
      backboardd <117d65aca8ce3ba68c7fd87d9ab81da6>      3424.058        6678              625           -          4409   50                       (daemon)
  UserEventAgent <2f6c74a697943aed899faebac621e4c3>       316.816         848                0           -          2101  200                       (daemon)
         configd <64e4db8bced23463b446c4b7c868fcfa>        31.906         416                0           -           933   50                       (daemon)
       fseventsd <a393d343a7533860b5c1eddb922a33f1>        20.088         405                0           -           805   50                       (daemon)
    fairplayd.H1 <c3856f0573fb3f9887721a239507f28b>        30.647         159                0           -          1096   50                       (daemon)
      assertiond <032107d4db2b36ddac986060d8c62f73>        26.282         289                0           -           702   50                       (daemon)
   wirelessproxd <ba82fe3b38f63f2b8b8807a2bf97aadd>         1.071         179                0           -           643   50                       (daemon)
       distnoted <e8f9e76e751838a880dad2d4a953f814>         4.457         193                0           -           254   50                       (daemon)
discoveryd_helpe <84abc0c6dd5b37a8b2c8323881e16da7>         0.493         123                0           -           466   50                       (daemon)
             ubd <5f4f0054821e3b41b543a4d9f4176291>         9.040         730                0           -          1540   50                       (daemon)
filecoordination <68a3848887853629adae42f5828a5443>         2.731         251                0           -           649  100                       (daemon)
      aggregated <ab0d307a392f36cc827709d24c4b8696>      1335.558        1081                0           -          1688   50                       (daemon)
      DTMobileIS <086152f142ac30a686a172b148d38fbc>       109.156         474                0           -          1724   50                       (daemon)
     touchsetupd <d8aabe65f2d23f6ab7704bbccc6c2ba1>         0.388         158                0           -           464   50                       (daemon)
        cfprefsd <6e5dcfe209183c719091d07edad590da>         0.150         166                0           -           320   50                       (daemon)
       accountsd <9eb0309b021033c6b24ce65da48fa228>         0.665         595                0           -          1909   50                       (daemon)
      CommCenter <0e1ced0eddce346ba27e9f54886ef025>       669.306        1543                0           -          4623   50                       (daemon)
         notifyd <7beaf472572334d4989a40473776f635>        61.698         272                0           -           309   50                       (daemon)
     ReportCrash <b36d5780860a3dfcbb146b2cc6bca339>         0.062         146                0           -           443   50                       (daemon)

**End**

UPDATE:

It turned out to be a memory issue. The app was allocating a lot of memory very quickly and the OS terminated the app. It was strange that Xcode did not log a memory warning while in Instruments show that the app received a LOT of warnings. Other apps that used the same amount of memory got away with no memory warnings. My guess is that those were not allocating memory at such a fast rate.

The app was running on an iPhone 4S and it got killed at around 90MB memory usage.

What confused me is other out of memory issues all had Purgeable pages: 0. So I'm guessing this is not exactly an out of memory but too much memory usage in a short time?

Solution 1

Just chipping in for anyone else who is struggling on this one.

For me the solution was to restart my device.

Solution 2

I had this same issue when loading a bunch of very large images (5000px x 5000px) in UIImages. Luckily the images were not supposed to be anywhere near that big and I just needed to resize them.

Solution 3

This bug appears frequently since I switched on iOS 11 Beta. Sometimes restarting the device works, sometimes my computer...

Solution 4

Yes, it is a memory issue, or you have opened too many threads. I have met this problem before. The problem I met like this:

When I delete a photo, which may cost about 0.2s, I would like to show a toast(MBProgressHUD) to user, and GCD to hide the toast after deleting.
When I tried to delete 100 photos, it is okay. However, when I tried to delete 200 photos, the app might be crashed. When I tried to delete 300 photos, the iPhone always restart itself.

Solution 5

Posting for posterity, as I recently experienced this 'crash' and it wasn't due to memory issues as others have suggested:

In rare cases, this can be an issue with the cord used to connect the iPhone to the computer. I had a faulty lightning cable, that would sporadically lose connection to my mac. The solution was to by a new one!

View more solutions

Comments

[aircraft]

do you mean when upload the image resize it ,or when download it to resize it?

[Wish]

Hi Andy, Did you find out any solution for this issue?

[Andy Darwin]

You have to figure out the wrong logic. My problem is showing MBProgressHUD 200 times in 1 second. There must be something wrong with your code logic.

[Jay Wong]

Is there a way to deallocate those UIImage's?

[coolcool1994]

I have the official latest version of iOS 11 on 10/4/2017, and I couldn't run my app from Xcode every time to my devices. Yesterday things were just fine. The solution was to restart my device like this person said. Thanks.

[Fattie]

it can DEFINITELY be the cable !

[Protocol]

This issue raised at my side when webservice response contains heavy data.

[aardvarkk]

A combination of rebooting the device and using a genuine cable seemed to help stability for me.