Android webview segfaults on display

Issue

I have a webview in a fragment. It has been working fine for a few months. I was playing around with the HTML embedded in it (a generated string) and i think it had a bad font reference.

The result is that now on one device this webview always segfaults when it displays - but only on the one device (a Galaxy Nexus) i was testing on - testing on other devices it all works fine. it load in the background in a viewpager so I know it initialises properly but when it display it always segfaults the app on this device.

So it looks like there is some cached data somewhere that is not being cleared. I cant understand why the same apk works on all other devices (all android versions - but only crashes on this one device.

i have tried to clear the cache using

_web.clearCache(true);
webSettings.setCacheMode(WebSettings.LOAD_NO_CACHE);

but no difference. Are there any other caches i can clear? I have rebooted the phone - no difference.

Looking for any ideas on how to resolve this error - no matter how crazy!

Here is the segfault - looks to be OpenGL related - -does the webview use opengl for fonts? - Is there a font cache for the webview?

D/TilesManager( 5776): new EGLContext from framework: 50c5df28 
D/GLWebViewState( 5776): Reinit shader
W/webcore ( 5776): skip viewSizeChanged as w is 0
D/GLWebViewState( 5776): Reinit transferQueue
D/MyPodV2 ( 5776): load page:0 - 0.0
D/MyPodV2 ( 5776): load page:720 - 100.0
F/libc    ( 5776): Fatal signal 11 (SIGSEGV) at 0x00000008 (code=1), thread 5776 (nelweb.mypod.v2)
I/DEBUG   (  121): *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
I/DEBUG   (  121): Build fingerprint: 'samsung/yakjuxw/maguro:4.1.1/JRO03C/I9250XWLH2:user/release-keys'
I/DEBUG   (  121): pid: 5776, tid: 5776, name: nelweb.mypod.v2  >>> co.uk.sentinelweb.mypod.v2 <<<
I/DEBUG   (  121): signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 00000008
I/DEBUG   (  121):     r0 00000008  r1 585b7008  r2 00000010  r3 00000004
I/DEBUG   (  121):     r4 56dbdb90  r5 56dbe9c0  r6 00000001  r7 00000004
I/DEBUG   (  121):     r8 00000008  r9 00000001  sl 00000004  fp 00000001
I/DEBUG   (  121):     ip 00000001  sp beac4180  lr 5863688c  pc 5865f774  cpsr 80000010
I/DEBUG   (  121):     d0  000000003e8374f1  d1  0000000000000000
I/DEBUG   (  121):     d2  3e8374f100000000  d3  0000000000000000
I/DEBUG   (  121):     d4  0000000000000000  d5  000000003f800000
I/DEBUG   (  121):     d6  426d42bcc1248268  d7  3f80000000000000
I/DEBUG   (  121):     d8  4411c6fc438013e9  d9  4507000000000000
I/DEBUG   (  121):     d10 43e72bda4481c000  d11 43e670f943e670f9
I/DEBUG   (  121):     d12 43e670f943e670f9  d13 bfa2695643f6cead
I/DEBUG   (  121):     d14 00000000bd134ab6  d15 0000000000000000
I/DEBUG   (  121):     d16 0000000800000000  d17 0000000000000000
I/DEBUG   (  121):     d18 0000000000000000  d19 0000000000000000
I/DEBUG   (  121):     d20 3ff0000000000000  d21 0000000000000000
I/DEBUG   (  121):     d22 0000000000000000  d23 0000000000000000
I/DEBUG   (  121):     d24 0000000000000000  d25 0000000000000000
I/DEBUG   (  121):     d26 0000000000000000  d27 0000000000000000
I/DEBUG   (  121):     d28 0000000000000000  d29 0000000000000000
I/DEBUG   (  121):     d30 0000000000000000  d31 0000000000000000
I/DEBUG   (  121):     scr 20000013
I/DEBUG   (  121): 
I/DEBUG   (  121): backtrace:
I/DEBUG   (  121):     #00  pc 00034774  /system/vendor/lib/egl/libGLESv2_POWERVR_SGX540_120.so
I/DEBUG   (  121):     #01  pc 0000b888  /system/vendor/lib/egl/libGLESv2_POWERVR_SGX540_120.so
I/DEBUG   (  121): 
I/DEBUG   (  121): stack:
I/DEBUG   (  121):          beac4140  03d00000  
I/DEBUG   (  121):          beac4144  00000000  
I/DEBUG   (  121):          beac4148  5c7b3dd0  
I/DEBUG   (  121):          beac414c  586d79f8  
I/DEBUG   (  121):          beac4150  56dbea6c  
I/DEBUG   (  121):          beac4154  585b6c7c  /dev/pvrsrvkm
I/DEBUG   (  121):          beac4158  00000002  
I/DEBUG   (  121):          beac415c  00000004  
I/DEBUG   (  121):          beac4160  56dbea6c  
I/DEBUG   (  121):          beac4164  56dbdb90  
I/DEBUG   (  121):          beac4168  56dbe9bc  
I/DEBUG   (  121):          beac416c  00000000  
I/DEBUG   (  121):          beac4170  00000004  
I/DEBUG   (  121):          beac4174  00000023  
I/DEBUG   (  121):          beac4178  df0027ad  
I/DEBUG   (  121):          beac417c  00000000  
I/DEBUG   (  121):     #00  beac4180  56dbdb90  
I/DEBUG   (  121):          ........  ........
I/DEBUG   (  121):     #01  beac4180  56dbdb90  
I/DEBUG   (  121):          beac4184  5863688c  /system/vendor/lib/egl/libGLESv2_POWERVR_SGX540_120.so
I/DEBUG   (  121):          beac4188  56dbdb90  
I/DEBUG   (  121):          beac418c  00000004  
I/DEBUG   (  121):          beac4190  00000004  
I/DEBUG   (  121):          beac4194  00000000  
I/DEBUG   (  121):          beac4198  00000005  
I/DEBUG   (  121):          beac419c  5863898c  /system/vendor/lib/egl/libGLESv2_POWERVR_SGX540_120.so
I/DEBUG   (  121):          beac41a0  56dbdb90  
I/DEBUG   (  121):          beac41a4  00000004  
I/DEBUG   (  121):          beac41a8  00000000  
I/DEBUG   (  121):          beac41ac  5868606c  /system/vendor/lib/egl/libGLESv2_POWERVR_SGX540_120.so
I/DEBUG   (  121):          beac41b0  00000005  
I/DEBUG   (  121):          beac41b4  58639a70  /system/vendor/lib/egl/libGLESv2_POWERVR_SGX540_120.so (glDrawArrays+804)
I/DEBUG   (  121):          beac41b8  00000004  
I/DEBUG   (  121):          beac41bc  00000000  
I/DEBUG   (  121): 
I/DEBUG   (  121): memory near r1:
I/DEBUG   (  121):     585b6fe8 ffffffff ffffffff ffffffff ffffffff  ................
I/DEBUG   (  121):     585b6ff8 ffffffff ffffffff ffffffff ffffffff  ................
I/DEBUG   (  121):     585b7008 ffffffff ffffffff ffffffff ffffffff  ................
I/DEBUG   (  121):     585b7018 ffffffff ffffffff ffffffff ffffffff  ................
I/DEBUG   (  121):     585b7028 ffffffff ffffffff ffffffff ffffffff  ................
I/DEBUG   (  121): 
I/DEBUG   (  121): memory near r4:
I/DEBUG   (  121):     56dbdb70 10000298 58ec5138 5dc1229f 00000298  ....8Q.X.".]....
I/DEBUG   (  121):     56dbdb80 58ca335c 5dbf356f 00000000 00000f9b  \3.Xo5.]........
I/DEBUG   (  121):     56dbdb90 00000018 0000e7fd 00001c80 00001100  ................
I/DEBUG   (  121):     56dbdba0 00001100 00000024 000003aa 00000064  ....$.......d...
I/DEBUG   (  121):     56dbdbb0 00000064 00000064 00000064 00000004  d...d...d.......
I/DEBUG   (  121): 
I/DEBUG   (  121): memory near r5:
I/DEBUG   (  121):     56dbe9a0 00000000 00000000 00000000 00000000  ................
I/DEBUG   (  121):     56dbe9b0 00000000 00000000 56dbe794 56dbe83c  ...........V<..V
I/DEBUG   (  121):     56dbe9c0 56dbe86c 00000000 00000000 00000000  l..V............
I/DEBUG   (  121):     56dbe9d0 00000000 00000000 00000000 00000000  ................
I/DEBUG   (  121):     56dbe9e0 00000002 00000003 00000003 00000004  ................
I/DEBUG   (  121): 
I/DEBUG   (  121): memory near sp:
I/DEBUG   (  121):     beac4160 56dbea6c 56dbdb90 56dbe9bc 00000000  l..V...V...V....
I/DEBUG   (  121):     beac4170 00000004 00000023 df0027ad 00000000  ....#....'......
I/DEBUG   (  121):     beac4180 56dbdb90 5863688c 56dbdb90 00000004  ...V.hcX...V....
I/DEBUG   (  121):     beac4190 00000004 00000000 00000005 5863898c  ..............cX
I/DEBUG   (  121):     beac41a0 56dbdb90 00000004 00000000 5868606c  ...V........l`hX
I/DEBUG   (  121): 
I/DEBUG   (  121): code around pc:
I/DEBUG   (  121):     5865f754 e781410c e28cc001 e15c0003 3afffffa  .A........\....:
I/DEBUG   (  121):     5865f764 e8bd8010 e92d4010 e3a0c000 ea000004  .....@-.........
I/DEBUG   (  121):     5865f774 e5904000 e5014008 e5904004 e0800002  .@...@...@......
I/DEBUG   (  121):     5865f784 e5014004 e15c0003 e2811008 e28cc001  .@....\.........
I/DEBUG   (  121):     5865f794 3afffff6 e8bd8010 e92d4010 e3a0c000  ...:.....@-.....
I/DEBUG   (  121): 
I/DEBUG   (  121): code around lr:
I/DEBUG   (  121):     5863686c e3530000 1a000005 e1a03007 e59c0018  ..S......0......
I/DEBUG   (  121):     5863687c e59c101c e59c2014 e1a0e00f e59cf024  ..... ......$...
I/DEBUG   (  121):     5863688c e2866001 e2855004 e5942e50 e3a03001  .`...P..P....0..
I/DEBUG   (  121):     5863689c e1560002 3affffeb e2840eed e1a01008  ..V....:........
I/DEBUG   (  121):     586368ac e280000c e1a02003 e8bd41f0 eaffe178  ..... ...A..x...
I/BootReceiver(  316): Copying /data/tombstones/tombstone_02 to DropBox (SYSTEM_TOMBSTONE)

UPDATE 10/03/13: this is the code that i use to stop caching - obviously i am getting a bit desperate.

_web.clearCache(true);
        _web.setAnimationCacheEnabled(false);
        _web.setDrawingCacheEnabled(false);
        _web.setAlwaysDrawnWithCacheEnabled(false);
        _web.clearHistory();
        _web.clearFormData();
        webSettings.setJavaScriptEnabled(false);
        webSettings.setCacheMode(WebSettings.LOAD_NO_CACHE);
        webSettings.setAppCacheMaxSize(0);
        webSettings.setAppCachePath("");
        webSettings.setAppCacheEnabled(false);
        getActivity().deleteDatabase("webview.db");
        getActivity().deleteDatabase("webviewCache.db");
        webSettings.setDomStorageEnabled(false);
        webSettings.setLoadsImagesAutomatically(false);
        _web.setWillNotCacheDrawing(true);
        webSettings.setBuiltInZoomControls(false);
        webSettings.setSupportZoom(false);
        webSettings.setSaveFormData(false);
        //_web.setWillNotDraw(true);// loads but stops drawing
        webSettings.setRenderPriority(WebSettings.RenderPriority.LOW);

Interesting to note that _web.setWillNotDraw(true); stops the segfault but does not draw anything (which is logical) so that indicates to me that segfault must be in the webview. drawing code.

Solution

Webview caches are app-specific, so uninstalling and reinstalling the app should fix this, if it was a temporary problem as you describe.

For more detail, caches live in:

/data/data/your.package.name/cache/

which you could have a look at, but then we get into the realms of whether you have access.

If your app was built for debug, then this adb command may let you see the directory contents:

run-as your.package.name ls /data/data/your.package.name/cache/

On my Galaxy S3 the related files are called 'webviewCacheChromiumStaging' and 'com.android.renderscript.cache', so your results may vary.

Answered By - Rob Pridham