747873 - Provide error information when input configuration not properly initialized

Status: RESOLVED FIXED

(Core :: Widget, defect)

Description

[Cervantes Yu [:cyu] [:cervantes]]

STR:
* on the device mv /system/usr/idc/sec_touchscreen.idc /system/usr/idc/sec_touchscreen.idc.bak to simulate idc file missing
* restart b2g and touch the home screen
* b2g reloads

Under some corner cases the device's input configuration is not properly configured. Files under /system/usr/idc/ can be missing and pointer device is initialized to default. When this happens, b2g process gets segv on touch. Here is the gdb session showing the symptom

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Breakpoint 1, GeckoInputReaderPolicy::obtainPointerController (this=0x422fb1c0, deviceId=6) at /home/cervantes/hg/mozilla-central/widget/gonk/nsAppShell.cpp:281
281         virtual sp<PointerControllerInterface> obtainPointerController(int32_t
(gdb) bt
#0  GeckoInputReaderPolicy::obtainPointerController (this=0x422fb1c0, deviceId=6) at /home/cervantes/hg/mozilla-central/widget/gonk/nsAppShell.cpp:281
#1  0x8297507c in android::TouchInputMapper::configureSurface (this=0x3a670, when=<optimized out>, outResetNeeded=0x43fffdb7) at /home/cervantes/hg/mozilla-central/widget/gonk/libui/InputReader.cpp:2694
#2  0x8297656e in android::TouchInputMapper::configure (this=0x3a670, when=1335175995285881000, config=0x43da2020, changes=0) at /home/cervantes/hg/mozilla-central/widget/gonk/libui/InputReader.cpp:2500
#3  0x8296cf6c in android::InputDevice::configure (this=0x39168, when=1335175995285881000, config=0x43da2020, changes=0) at /home/cervantes/hg/mozilla-central/widget/gonk/libui/InputReader.cpp:910

...(some lines are omitted)

Program received signal SIGSEGV, Segmentation fault.
android::TouchInputMapper::preparePointerGestures (this=0x3a670, when=1335176027728114000, outCancelPreviousGesture=0x43fffd37, outFinishPreviousGesture=0x43fffd36, isTimeout=<optimized out>)
    at /home/cervantes/hg/mozilla-central/widget/gonk/libui/InputReader.cpp:4533
4533            mPointerController->getPosition(&x, &y);
(gdb) bt
#0  android::TouchInputMapper::preparePointerGestures (this=0x3a670, when=1335176027728114000, outCancelPreviousGesture=0x43fffd37, outFinishPreviousGesture=0x43fffd36, isTimeout=<optimized out>)
    at /home/cervantes/hg/mozilla-central/widget/gonk/libui/InputReader.cpp:4533
#1  0x829725fc in android::TouchInputMapper::dispatchPointerGestures (this=0x0, when=<optimized out>, policyFlags=0, isTimeout=48)
    at /home/cervantes/hg/mozilla-central/widget/gonk/libui/InputReader.cpp:3959
#2  0x82972d48 in android::TouchInputMapper::dispatchPointerUsage (this=0x3a670, when=1335176027728114000, policyFlags=0, pointerUsage=android::TouchInputMapper::POINTER_USAGE_GESTURES)
    at /home/cervantes/hg/mozilla-central/widget/gonk/libui/InputReader.cpp:3923
#3  0x82973ac4 in android::TouchInputMapper::sync (this=0x3a670, when=1335176027728114000) at /home/cervantes/hg/mozilla-central/widget/gonk/libui/InputReader.cpp:3423
#4  0x82973c36 in android::TouchInputMapper::process (this=0x3a670, rawEvent=0x43da2180) at /home/cervantes/hg/mozilla-central/widget/gonk/libui/InputReader.cpp:3299
#5  0x82973c4c in android::MultiTouchInputMapper::process (this=0x0, rawEvent=0x43fff778) at /home/cervantes/hg/mozilla-central/widget/gonk/libui/InputReader.cpp:5571
#6  0x82976634 in android::InputDevice::process (this=0x39168, rawEvents=<optimized out>, count=1) at /home/cervantes/hg/mozilla-central/widget/gonk/libui/InputReader.cpp:961
#7  0x829766a4 in android::InputReader::processEventsForDeviceLocked (this=<optimized out>, deviceId=6, rawEvents=0x43da20c0, count=7)
    at /home/cervantes/hg/mozilla-central/widget/gonk/libui/InputReader.cpp:459
#8  0x82977428 in android::InputReader::processEventsLocked (this=0x43da2000, rawEvents=<optimized out>, count=7) at /home/cervantes/hg/mozilla-central/widget/gonk/libui/InputReader.cpp:321
#9  0x82977654 in android::InputReader::loopOnce (this=0x43da2000) at /home/cervantes/hg/mozilla-central/widget/gonk/libui/InputReader.cpp:283
#10 0x8296cf08 in android::InputReaderThread::threadLoop (this=<optimized out>) at /home/cervantes/hg/mozilla-central/widget/gonk/libui/InputReader.cpp:838
#11 0xa811dd28 in android::Thread::_threadLoop (user=<optimized out>) at frameworks/base/libs/utils/Threads.cpp:770
#12 0xa811e2ea in thread_data_t::trampoline (t=<optimized out>) at frameworks/base/libs/utils/Threads.cpp:127
#13 0xafd11c38 in __thread_entry (func=0xa811e24d <thread_data_t::trampoline(thread_data_t const*)>, arg=0x2bd80, tls=<optimized out>) at bionic/libc/bionic/pthread.c:213
#14 0xafd117ec in pthread_create (thread_out=<optimized out>, attr=0xbe8b14d4, start_routine=0xa811e24d <thread_data_t::trampoline(thread_data_t const*)>, arg=<optimized out>)

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The problem originates from program flow enters GeckoInputReaderPolicy::obtainPointerController(), which should never be called in our case (and returns NULL).
We might consider add MOZ_NOTREACHED() here to die early on such cases or add log print indicating something wrong happened.

Comment 1

[Cervantes Yu [:cyu] [:cervantes]]

MOZ_NOT_REACHED() might be too over here because GeckoInputReaderPolicy::obtainPointerController () is in startup code.

Comment 2

[Cervantes Yu [:cyu] [:cervantes]]

Attachment: Add MOZ_NOT_REACHED() in code path that should never be reached

Comment 3

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/9dc532ce5de7

Comment 4

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/9dc532ce5de7