JDK-8049253: JVM crashes when GC log rotation is invoked with long path.

[Yumin Qi]

Yasumasa,

   Thanks for finding and fix the issue. It looks good --- but I am not 
a "R"eviewer so need a reviewer's Yes on the change, I can be sponsor to 
integrate your changeset.

Yumin

On 7/3/2014 7:19 AM, Yasumasa Suenaga wrote:
> Hi all,
>
> JVM crashes when GC log rotation is invoked with long path ( >= 1024)
> I filed testcase of this issue.
>
>
> HOW TO REPRODUCE:
>
>  1. Extract TAR ball (testcase.tar.gz: Attached to JBS)
>
>  2. Compile SystemGC.java
>
>  3. Run java as following:
>     $ 
> /usr/src/OpenJDK/hs-gc/build/linux-x86_64-normal-server-release/images/j2sdk-image/bin/java 
> -Xloggc:`cat longpath.txt` -XX:+UseGCLogFileRotation 
> -XX:NumberOfGCLogFiles=2 SystemGC
>            or
>     $ 
> /usr/src/OpenJDK/hs-gc/build/linux-x86_64-normal-server-release/images/j2sdk-image/bin/java 
> -Xloggc:`cat maxpath.txt` -XX:+UseGCLogFileRotation 
> -XX:NumberOfGCLogFiles=2 SystemGC
>
>   4. Invoke GC log file rotation from jcmd:
>     $ jcmd <PID> GC.rotate_log
>
>
> Cause of this crash is stack memory corruption in 
> gcLogFileStream::rotate_log() .
> Current implementation, length of GC log file name is defined as 
> FILENAMEBUFLEN macro.
> It is defined to 1024.
> However, buffer of actual file name is allocated dynamically and its 
> length may be over 1024.
> In this case, stack memory corruption is occurred.
> -----------
>  char current_file_name[FILENAMEBUFLEN];
>  char renamed_file_name[FILENAMEBUFLEN];
>     :
>  size_t filename_len = strlen(_file_name);
>  if (_file != NULL) {
>    jio_snprintf(renamed_file_name, filename_len + EXTRACHARLEN, "%s.%d",
>                 _file_name, _cur_file_num);
>    jio_snprintf(current_file_name, filename_len + EXTRACHARLEN, 
> "%s.%d" CURRENTAPPX,
>                 _file_name, _cur_file_num);
>     :
> -----------
>
> It is rare. However it is critical.
>
> I've created a patch for this issue and uploaded webrev.
> It is work fine on my environment.
>
> http://cr.openjdk.java.net/~ysuenaga/JDK-8049253/webrev.0/
>
> I would like to contribute this patch.
> Please cooperate.
>
>
> Thanks,
>
> Yasumasa
>