Uploaded image for project: 'JDK'
  1. JDK
  2. JDK-8283408

Fix a C2 crash when filling arrays with unsafe

    XMLWordPrintable

    Details

    • Subcomponent:
    • Resolved In Build:
      b16
    • CPU:
      generic
    • OS:
      generic

      Backports

        Description

        HotSpot C2 crashes when we use unsafe API to fill an array in a loop. It can be reproduced by the case like below.

                byte[] array = new byte[size];
                int offset = unsafe.arrayBaseOffset(byte[].class);
                for (int i = offset; i < offset + size; i++) {
                     unsafe.putByte(array, i, fill);
                }

        Crash report

        #
        # A fatal error has been detected by the Java Runtime Environment:
        #
        # SIGSEGV (0xb) at pc=0x0000ffffb60c5988, pid=2413836, tid=2413852
        #
        # JRE version: OpenJDK Runtime Environment (19.0) (fastdebug build 19-internal-adhoc.penli01.jdksrc)
        # Java VM: OpenJDK 64-Bit Server VM (fastdebug 19-internal-adhoc.penli01.jdksrc, mixed mode, sharing, tiered, compressed oops, compressed class ptrs, g1 gc, linux-aarch64)
        # Problematic frame:
        # V [libjvm.so+0x6c5988] AddPNode::bottom_type() const+0x78
        #
        # Core dump will be written. Default location: /tmp/core.2413836
        #
        # An error report file with more information is saved as:
        # /tmp/scratch/0/hs_err_pid2413836.log
        #
        # Compiler replay data is saved as:
        # /tmp/scratch/0/replay_pid2413836.log
        #
        # If you would like to submit a bug report, please visit:
        # https://bugreport.java.com/bugreport/crash.jsp
        #


        The crash is caused by a NULL pointer issue when doing loop intrinsify_fill optimization for unsafe fill patterns. Although this only occurs with unsafe call, we still think it's better to fix that because such unsafe call is used in a correct way.

        Note that this can be reproduced on AArch64 with default VM options. On x86, it's reproducible with additional option "-XX:+OptimizeFill" which is turned off by default.

          Attachments

            Issue Links

              Activity

                People

                Assignee:
                pli Pengfei Li
                Reporter:
                pli Pengfei Li
                Votes:
                0 Vote for this issue
                Watchers:
                7 Start watching this issue

                  Dates

                  Created:
                  Updated:
                  Resolved: