[OpenJDK 2D-Dev] Crash in CGraphicsDevice.m

[Phil Race]

Hi,

I expect it would be a good & safe thing to do, to check for NULL.
But I don't know if all of these reports you have are down to that.
Did you get stack traces for all of them ?
We also have open bugs like
https://bugs.openjdk.java.net/browse/JDK-8146329
https://bugs.openjdk.java.net/browse/JDK-8133783
which look different.

-phil.

On 10/10/2018 10:56 AM, Bill York wrote:
>
> Thanks for the response Phil, here’s what I know.
>
> Reports show:
>
>   * Mac OS – many versions 10.10 through 17.7
>   * Java - 8 u144-b01 (48 reports), 8 u152-b16 (12 reports) 8
>     u152-release-1136-b5 – JetBrains (1 report)
>
> Comments say:
>
>   * Screen change event.  I am using the jetbrains JRE, as you can see
>     in the stack trace.
>   * I am on a mac and product crashes very often when I put my
>     computer to sleep.
>   * Woke up computer after connecting to two external monitors.
>
> I’ve annotated the function names with links to code I found on the 
> OpenJDK site and the Apple site.
>
> As an experiment, I created a simple X-Code project to examine how 
> CFSTringCompare behaves when passed NULL. It does throw an 
> EXC_BAD_ACCESS as is shown in the below stack trace. My example code 
> is at the end of this message.
>
> Stack trace shows:
>
> [  7] 0x00006000001c5848 <unknown-module>+00000000
>
> [  8] 0x00007fff3cc4e678 
> /System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation+00140920CFStringCompare 
> <https://developer.apple.com/documentation/corefoundation/1542911-cfstringcompare?language=objc>+00000024
>
> [  9] 0x00000001351a80f7 
> java/jre/maci64/jre/lib/libawt_lwawt.dylib+00119031 
> getBPPFromModeString 
> <http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/687fd7c7986d/src/macosx/native/sun/awt/CGraphicsDevice.m>+00000032 
> (see line 32)
>
> [ 10] 0x00000001351a819f 
> java/jre/maci64/jre/lib/libawt_lwawt.dylib+00119199 
> createJavaDisplayMode 
> <http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/687fd7c7986d/src/macosx/native/sun/awt/CGraphicsDevice.m>+00000053 
> (see line 130)
>
> [ 11] 0x00000001351a841e 
> java/jre/maci64/jre/lib/libawt_lwawt.dylib+00119838 
> Java_sun_awt_CGraphicsDevice_nativeGetDisplayMode 
> <http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/687fd7c7986d/src/macosx/native/sun/awt/CGraphicsDevice.m>+00000031 
> (see line 267)
>
> Example code:
>
> #import <Foundation/Foundation.h>
>
> static int getBPPFromModeString(CFStringRef mode)
>
> {
>
> if((CFStringCompare(mode, CFSTR(kIO30BitDirectPixels), 
> kCFCompareCaseInsensitive) == kCFCompareEqualTo)) {
>
> // This is a strange mode, where we using 10 bits per RGB component 
> and pack it into 32 bits
>
> // Java is not ready to work with this mode but we have to specify it 
> as supported
>
> return 30;
>
> }
>
> elseif(CFStringCompare(mode, CFSTR(IO32BitDirectPixels), 
> kCFCompareCaseInsensitive) == kCFCompareEqualTo) {
>
> return 32;
>
> }
>
> elseif(CFStringCompare(mode, CFSTR(IO16BitDirectPixels), 
> kCFCompareCaseInsensitive) == kCFCompareEqualTo) {
>
> return 16;
>
> }
>
> elseif(CFStringCompare(mode, CFSTR(IO8BitIndexedPixels), 
> kCFCompareCaseInsensitive) == kCFCompareEqualTo) {
>
> return 8;
>
> }
>
> return0;
>
> }
>
> int main(int argc, const char * argv[]) {
>
> @autoreleasepool{
>
> // insert code here...
>
> CFStringRef mode;
>
> getBPPFromModeString(mode);
>
> NSLog(@"Hello, World!");
>
> }
>
> return0;
>
> }
>
> *From: *Philip Race <philip.race at oracle.com>
> *Organization: *Oracle Corporation
> *Date: *Wednesday, October 10, 2018 at 12:03 PM
> *To: *Bill York <Bill.York at mathworks.com>
> *Cc: *"2d-dev at openjdk.java.net" <2d-dev at openjdk.java.net>
> *Subject: *Re: [OpenJDK 2D-Dev] Crash in CGraphicsDevice.m
>
> The code you suspect has nothing to do with the webrev you list.
> It was introduced in fixing 
> https://bugs.openjdk.java.net/browse/JDK-7124247 
> <https://bugs.openjdk.java.net/browse/JDK-7124247>
> So has been there since JDK 8 GA. Not recent .. perhaps you can tell us
> more about your users JDK versions and what is the earliest that 
> reproduces this crash ?
>
> -phil.
>
> On 10/10/18, 8:45 AM, Bill York wrote:
>
>     2d-dev folks,
>
>     I work on a product called MATLAB and we have about 60 reports
>     from customers on Mac related to a crash in CGraphicsDevice.m
>
>     Please let  me know if this is the right way to report a crash and
>     discuss getting it resolved.
>
>     Here are the details:
>
>     CGraphicsDevice.m is a native file in support of Java drawing and
>     gets called from Java_sun_awt_CGraphicsDevice_nativeGetDisplayMode
>
>     While I can’t reproduce the problem, it looks like the display
>     pointer is becoming invalid for a time when the user’s laptop
>     opens or closes.
>
>     Looking at this source code:
>
>     http://cr.openjdk.java.net/~serb/8000629/webrev.08/src/macosx/native/sun/awt/CGraphicsDevice.m.html
>     <http://cr.openjdk.java.net/%7Eserb/8000629/webrev.08/src/macosx/native/sun/awt/CGraphicsDevice.m.html>
>
>     I see a direct call to CFStringCompare without a check for a NULL
>     CFStringRef.
>
>       * (CFStringCompare(mode, CFSTR(kIO30BitDirectPixels),
>         kCFCompareCaseInsensitive) == kCFCompareEqualTo)
>
>     I believe if this code returned 0, the crash would not occur
>     though there may be some other cleanup in the surrounding call frames.
>
>     Bill
>

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