Segementation Fault When Reading File With Java App

[jeloba]

Bug Description

Reading a file in a Java app (running in a VS Code debugger) triggers a segmentation fault:

#
# A fatal error has been detected by the Java Runtime Environment:
#
#  SIGSEGV (0xb) at pc=0x00007f33526e66aa, pid=127287, tid=127295
#
# JRE version: OpenJDK Runtime Environment (17.0.8.1+1) (build 17.0.8.1+1-Ubuntu-0ubuntu122.04)
# Java VM: OpenJDK 64-Bit Server VM (17.0.8.1+1-Ubuntu-0ubuntu122.04, mixed mode, sharing, tiered, compressed oops, compressed class ptrs, g1 gc, linux-amd64)
# Problematic frame:
# C  [libc.so.6+0xe66aa]  readdir64+0x2a
#
# No core dump will be written. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again
#
# An error report file with more information is saved as:
# hs_err_pid127287.log
#
# If you would like to submit a bug report, please visit:
#   Unknown
# The crash happened outside the Java Virtual Machine in native code.
# See problematic frame for where to report the bug.
#

The config in use contains the following stanza:

{
    "feature": {
        "fs": {
          "mode": "read",
          "read_only": [ "/etc/*" ]
        }
    }
}

Steps to Reproduce

1. configure and enable mirrord
2. start a debugging session

Backtrace

Current thread (0x00007f3344046e10):  JavaThread "main" [_thread_in_native, id=127295, stack(0x00007f3350f00000,0x00007f3351000000)]

Stack: [0x00007f3350f00000,0x00007f3351000000],  sp=0x00007f3350ffdfd0,  free space=1015k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
C  [libc.so.6+0xe66aa]  readdir64+0x2a

Java frames: (J=compiled Java code, j=interpreted, Vv=VM code)
j  sun.nio.fs.UnixNativeDispatcher.readdir(J)[B+0 java.base@17.0.8.1
j  sun.nio.fs.UnixDirectoryStream$UnixDirectoryIterator.readNextEntry()Ljava/nio/file/Path;+52 java.base@17.0.8.1
j  sun.nio.fs.UnixDirectoryStream$UnixDirectoryIterator.hasNext()Z+16 java.base@17.0.8.1
j  java.nio.file.FileTreeWalker.next()Ljava/nio/file/FileTreeWalker$Event;+37 java.base@17.0.8.1
j  java.nio.file.Files.walkFileTree(Ljava/nio/file/Path;Ljava/util/Set;ILjava/nio/file/FileVisitor;)Ljava/nio/file/Path;+255 java.base@17.0.8.1
j  java.nio.file.Files.walkFileTree(Ljava/nio/file/Path;Ljava/nio/file/FileVisitor;)Ljava/nio/file/Path;+11 java.base@17.0.8.1
[...more]

Relevant Logs

No response

Your operating system and version

Ubuntu 22.04.3 LTS

Local process

Java debugger in VS Code

Local process version

No response

Additional Info

For additional context:

• The location that is accessed is provided by the Vault agent. So it's not located on the main file system.
• Listing all files in "/" returns results form the local system.
• Listing all files in "/etc" causes a crash.

[Razz4780]

We found the source of the bug and fixed it in #2003
All should work with the next release :)

[eyalb181]

@jeloba Hey, just letting you know version 3.72.0 of the mirrord binary is now out and contains the fix. Update happens automatically on the VS Code extension. Please let us know if the issue recurs!

[jeloba]

I gave it a try and the issue is resolved. Thanks @Razz4780 and @eyalb181 !