EXC_BAD_ACCESS Attempted to dereference garbage pointer 0x871dcbeb8

[dwilt]

"react-native": "0.41.2",
"react-native-fetch-blob": "0.10.2",

Got a crash while using our app. Not totally sure what the repro steps are but wanted to put this out there.

EXC_BAD_ACCESS Attempted to dereference garbage pointer 0x871dcbeb8. 
    /usr/lib/libobjc.A.dylib objc_msgSend
    Frameworks/Foundation.framework/Foundation -[NSObject(NSKeyValueObservingPrivate) _changeValueForKey:key:key:usingBlock:]
    Frameworks/Foundation.framework/Foundation -[NSOperationQueue setMaxConcurrentOperationCount:]
    /Users/dwilt/Projects/GJS/gjs-app/node_modules/react-native-fetch-blob/ios/RNFetchBlobNetwork.m:114:19 -[RNFetchBlobNetwork init]
    /Users/dwilt/Projects/GJS/gjs-app/node_modules/react-native-fetch-blob/ios/RNFetchBlob/RNFetchBlob.m:102:46 __65-[RNFetchBlob fetchBlob:taskId:method:url:headers:body:callback:]_block_invoke
    /Users/dwilt/Projects/GJS/gjs-app/node_modules/react-native-fetch-blob/ios/RNFetchBlobReqBuilder.m:160:9 __85+[RNFetchBlobReqBuilder buildOctetRequest:taskId:method:url:headers:body:onComplete:]_block_invoke
    /usr/lib/system/libdispatch.dylib __dispatch_call_block_and_release
    /usr/lib/system/libdispatch.dylib __dispatch_client_callout
    /usr/lib/system/libdispatch.dylib __dispatch_queue_override_invoke
    /usr/lib/system/libdispatch.dylib __dispatch_root_queue_drain
    /usr/lib/system/libdispatch.dylib __dispatch_worker_thread3
    /usr/lib/system/libsystem_pthread.dylib __pthread_wqthread

[wkh237]

@dwilt , could you provide a sample about your usage which can replicate the error?

[GaborWnuk]

Hi! I also have this problem, can't replicate whatsoever:

# Issue #: 3121
# Issue ID: 58cbfcf70aeb16625b824896
# Session ID: 106ae09fabfd479a8b692f05b6bbd9ab_9f34c65b3a0d4190bb2c0d88a6fe659f_0_v1
# Date: 2017-04-18T08:50:19Z
# OS Version: 10.3.1 (14E304)
# Device: iPhone 7
# RAM Free: 13.3%
# Disk Free: 35.9%

#4. Crashed: com.apple.root.default-qos
0  libobjc.A.dylib                0x182dd4150 objc_msgSend + 16
1  Foundation                     0x184d62c94 -[NSObject(NSKeyValueObservingPrivate) _changeValueForKey:key:key:usingBlock:] + 60
2  Foundation                     0x184d8aa5c -[NSOperationQueue setMaxConcurrentOperationCount:] + 204
3  Xxxxxxx                        0x1002fe3ac -[RNFetchBlobNetwork init] (RNFetchBlobNetwork.m:117)
4  Xxxxxxx                        0x1002f4b10 __65-[RNFetchBlob fetchBlob:taskId:method:url:headers:body:callback:]_block_invoke (RNFetchBlob.m:131)
5  Xxxxxxx                        0x1003031c4 __85+[RNFetchBlobReqBuilder buildOctetRequest:taskId:method:url:headers:body:onComplete:]_block_invoke (RNFetchBlobReqBuilder.m:178)
6  libdispatch.dylib              0x1832169e0 _dispatch_call_block_and_release + 24
7  libdispatch.dylib              0x1832169a0 _dispatch_client_callout + 16
8  libdispatch.dylib              0x1832250d4 _dispatch_queue_override_invoke + 644
9  libdispatch.dylib              0x183226a50 _dispatch_root_queue_drain + 540
10 libdispatch.dylib              0x1832267d0 _dispatch_worker_thread3 + 124
11 libsystem_pthread.dylib        0x18341f1d0 _pthread_wqthread + 1096
12 libsystem_pthread.dylib        0x18341ed7c start_wqthread + 4

It is not OS version specific (i have crashes on iOS 9 and 10) or phone specific (also - full range of devices).

The problem is quite rare (around 1% of my users on scale of few thousand) however - it does exist.

The view consists of ~15 images displayed in ListView, with following render conditions for ListView:

initialListSize={3}
scrollRenderAheadDistance={Dimensions.get("window").height * 3}
pageSize={2}

as cells are quite big.

[knutvalen]

I also got the same problem as @GaborWnuk. The view is a ListView with one Image in each row.

# Issue #: 11
# Issue ID: 58ef3d0f0aeb16625b9db7bd
# Session ID: cf40838edb814dcaaaa7db573ea9c141_1d0b9e3debdf4c20a45a5eb09689e102_0_v1
# Date: 2017-05-04T13:28:19Z
# OS Version: 10.3.1 (14E304)
# Device: iPhone 6s
# RAM Free: 9.4%
# Disk Free: 14%

#2. Crashed: com.apple.root.default-qos
0  libobjc.A.dylib                0x1854a4150 objc_msgSend + 16
1  Foundation                     0x1874ea85c -[NSObject(NSKeyValueObservingPrivate) _changeValueForKeys:count:maybeOldValuesDict:usingBlock:] + 188
2  Foundation                     0x187432c94 -[NSObject(NSKeyValueObservingPrivate) _changeValueForKey:key:key:usingBlock:] + 60
3  Foundation                     0x18745aa5c -[NSOperationQueue setMaxConcurrentOperationCount:] + 204
4  x                              0x100136434 -[RNFetchBlobNetwork init] + 4296729652
5  x                              0x10013d758 __65-[RNFetchBlob fetchBlob:taskId:method:url:headers:body:callback:]_block_invoke + 4296759128
6  x                              0x10013b790 __85+[RNFetchBlobReqBuilder buildOctetRequest:taskId:method:url:headers:body:onComplete:]_block_invoke + 4296750992
7  libdispatch.dylib              0x1858e69e0 _dispatch_call_block_and_release + 24
8  libdispatch.dylib              0x1858e69a0 _dispatch_client_callout + 16
9  libdispatch.dylib              0x1858f50d4 _dispatch_queue_override_invoke + 644
10 libdispatch.dylib              0x1858f6a50 _dispatch_root_queue_drain + 540
11 libdispatch.dylib              0x1858f67d0 _dispatch_worker_thread3 + 124
12 libsystem_pthread.dylib        0x185aef1d0 _pthread_wqthread + 1096
13 libsystem_pthread.dylib        0x185aeed7c start_wqthread + 4

[kelset]

Similar situation over here too, we have a SectionList (RN 0.44) with two images in each row.

Crashed: com.apple.root.default-qos
0  libobjc.A.dylib                0x189904150 objc_msgSend + 16
1  Foundation                     0x18b94a82c -[NSObject(NSKeyValueObservingPrivate) _changeValueForKeys:count:maybeOldValuesDict:usingBlock:] + 140
2  Foundation                     0x18b892c94 -[NSObject(NSKeyValueObservingPrivate) _changeValueForKey:key:key:usingBlock:] + 60
3  Foundation                     0x18b8baa5c -[NSOperationQueue setMaxConcurrentOperationCount:] + 204
4  TheWeek                        0x1004eb8a4 -[RNFetchBlobNetwork init] (RNFetchBlobNetwork.m:112)
5  TheWeek                        0x1004f2b00 __65-[RNFetchBlob fetchBlob:taskId:method:url:headers:body:callback:]_block_invoke (RNFetchBlob.m:131)
6  TheWeek                        0x1004f0b14 __85+[RNFetchBlobReqBuilder buildOctetRequest:taskId:method:url:headers:body:onComplete:]_block_invoke (RNFetchBlobReqBuilder.m:178)
7  libdispatch.dylib              0x189d469e0 _dispatch_call_block_and_release + 24
8  libdispatch.dylib              0x189d469a0 _dispatch_client_callout + 16
9  libdispatch.dylib              0x189d550d4 _dispatch_queue_override_invoke + 644
10 libdispatch.dylib              0x189d56a50 _dispatch_root_queue_drain + 540
11 libdispatch.dylib              0x189d567d0 _dispatch_worker_thread3 + 124
12 libsystem_pthread.dylib        0x189f4f1d0 _pthread_wqthread + 1096
13 libsystem_pthread.dylib        0x189f4ed7c start_wqthread + 4

We are also using this lib ( react-native-img-cache ) for caching, which relies on react-native-fetch-blob.

[samueljmurray]

Also having this issue (RN 0.43) and using react-native-img-cache too. All images are used in a FlatList. Similar to @GaborWnuk this has affected ~1% (40) out of a few thousand users. Only on iOS 10, though our sample probably isn't big enough for this to be meaningful as we only support down to 9.3.5.

Crashed: com.apple.root.default-qos
0  libobjc.A.dylib                0x18f1f6f30 objc_msgSend + 16
1  Foundation                     0x19125b738 -[NSObject(NSKeyValueObservingPrivate) _changeValueForKeys:count:maybeOldValuesDict:usingBlock:] + 176
2  Foundation                     0x1911a3a40 -[NSObject(NSKeyValueObservingPrivate) _changeValueForKey:key:key:usingBlock:] + 64
3  Foundation                     0x1911cb3f0 -[NSOperationQueue setMaxConcurrentOperationCount:] + 204
4  MyApp                          0x100291644 -[RNFetchBlobNetwork init] + 463760
5  MyApp                          0x100298968 __65-[RNFetchBlob fetchBlob:taskId:method:url:headers:body:callback:]_block_invoke + 493236
6  MyApp                          0x1002969a0 __85+[RNFetchBlobReqBuilder buildOctetRequest:taskId:method:url:headers:body:onComplete:]_block_invoke + 485100
7  libdispatch.dylib              0x18f635200 _dispatch_call_block_and_release + 24
8  libdispatch.dylib              0x18f6351c0 _dispatch_client_callout + 16
9  libdispatch.dylib              0x18f643ab4 _dispatch_queue_override_invoke + 732
10 libdispatch.dylib              0x18f64538c _dispatch_root_queue_drain + 572
11 libdispatch.dylib              0x18f6450ec _dispatch_worker_thread3 + 124
12 libsystem_pthread.dylib        0x18f83e2b8 _pthread_wqthread + 1288
13 libsystem_pthread.dylib        0x18f83dda4 start_wqthread + 4

[kelset]

Any update on this? I've updated my app to 0.45 and I still have this issue, on a small number of iPhones with iOS 10.x

[wkh237]

I have tried to find the problem but unfortunately couldn't find a way to reproduce it, I think if there's sample for replicate the issue would be helpful.