JNI WARNING: input is not valid Modified UTF-8: illegal start byte 0xfe

W/dalvikvm( 1473): in Landroid/media/MediaScanner;.processFile (Ljava/lang/String;Ljava/lang/String;Landroid/media/MediaScannerClient;)V (NewStringUTF)

I/dalvikvm( 1473): "MediaScannerService" prio=5 tid=10 NATIVE

I/dalvikvm( 1473): | group="main" sCount=0 dsCount=0 s=N obj=0x45f1ea18 self=0x22f0d0

I/dalvikvm( 1473): | sysTid=1647 nice=11 sched=3/0 cgrp=unknown handle=2229456

I/dalvikvm( 1473): at android.media.MediaScanner.processFile(Native Method)

I/dalvikvm( 1473): at android.media.MediaScanner.access$500(MediaScanner.java:103)

这个就是蛋疼的地方，

造成该问题的原因是没有通过虚拟机的checkjni检查。代码在dalvik/vm/CheckJni.c

/*

* Verify that "bytes" points to valid "modified UTF-8" data.

*/

static void checkUtfString(JNIEnv* env, const char* bytes, bool nullOk,

const char* func)

{

const char* origBytes = bytes;

if (bytes == NULL) {

if (!nullOk) {

LOGW("JNI WARNING: unexpectedly null UTF string/n");

goto fail;

}

return;

}

while (*bytes != '/0') {

u1 utf8 = *(bytes++);

// Switch on the high four bits.

switch (utf8 >> 4) {

case 0x00:

case 0x01:

case 0x02:

case 0x03:

case 0x04:

case 0x05:

case 0x06:

case 0x07: {

// Bit pattern 0xxx. No need for any extra bytes.

break;

}

case 0x08:

case 0x09:

case 0x0a:

case 0x0b:

case 0x0f: {

/*

* Bit pattern 10xx or 1111, which are illegal start bytes.

* Note: 1111 is valid for normal UTF-8, but not the

* modified UTF-8 used here.

*/

LOGW("JNI WARNING: illegal start byte 0x%x/n", utf8);

goto fail;

}

case 0x0e: {

// Bit pattern 1110, so there are two additional bytes.

utf8 = *(bytes++);

if ((utf8 & 0xc0) != 0x80) {

LOGW("JNI WARNING: illegal continuation byte 0x%x/n", utf8);

goto fail;

}

// Fall through to take care of the final byte.

}

case 0x0c:

case 0x0d: {

// Bit pattern 110x, so there is one additional byte.

utf8 = *(bytes++);

if ((utf8 & 0xc0) != 0x80) {

LOGW("JNI WARNING: illegal continuation byte 0x%x/n", utf8);

goto fail;

}

break;

}

}

}

return;

fail:

LOGW(" string: '%s'/n", origBytes);

showLocation(dvmGetCurrentJNIMethod(), func);

abortMaybe();

}

解决方法：

是否进行checkjni检查是由ro.kernel.android.checkjni决定。

在eng版本中ro.kernel.android.checkjni=1.而在user, userdebug版本不做检查

In build/core/main.mk

user_variant := $(filter user userdebug,$(TARGET_BUILD_VARIANT))

enable_target_debugging := true

tags_to_install :=

ifneq (,$(user_variant))

...

ro.kernel.android.checkjni=0

else

...

ro.kernel.android.checkjni=1

note: 遇到了一次这个问题，kernel层上传的字符窜格式是S8, 长层接收转换时出错。