Syscall fault injection

Force the 3rd openat to fail with ENOENT to test error handling; chaos testing without code

strace -f -e inject=openat:error=ENOENT:when=3 -p <pid>
tool
strace13 commands
tags
stracedebugtroubleshootingci

More strace commands

  • Trace signals delivered
    strace -f -e signal=all -e trace=none -p <pid>

    Show only signals (SIGTERM/SIGCHLD) and skip syscalls; debug mysterious kills. note: ltrace for libcalls

  • Trace a new process
    strace -o trace.log ls /tmp

    Run a command under strace and save output to file

  • Attach to running process
    strace -p $(pgrep nginx | head -1) -o /tmp/nginx.trace

    Trace syscalls of an already-running process by PID

  • Trace only specific syscalls
    strace -e trace=openat,read,write curl https://example.com

    Filter to file-related syscalls only

  • Count syscall statistics
    strace -c -e trace=all python3 app.py

    Summary table of syscall counts and time spent

all 13 strace commands