Parse Rust Panic Stack Trace (Backtrace)
Parse Rust panic backtraces. Extract function symbols, demangled names, file paths, and line numbers from Rust runtime panic output with RUST_BACKTRACE=1.
Detailed Explanation
Understanding Rust Panic Backtraces
Rust panics are fundamentally different from exceptions in other languages. A panic unwinds the stack (by default) and terminates the thread. The backtrace is displayed when the RUST_BACKTRACE=1 or RUST_BACKTRACE=full environment variable is set.
Rust Backtrace Format
thread 'main' panicked at 'index out of bounds: the len is 3 but the index is 5', src/main.rs:15:10
stack backtrace:
0: rust_begin_unwind
at /rustc/xxx/library/std/src/panicking.rs:578:5
1: core::panicking::panic_fmt
at /rustc/xxx/library/core/src/panicking.rs:67:14
2: core::panicking::panic_bounds_check
at /rustc/xxx/library/core/src/panicking.rs:162:5
3: my_app::process_items
at ./src/main.rs:15:10
4: my_app::main
at ./src/main.rs:8:5
Backtrace Components
- Thread name ---
thread 'main'identifies which thread panicked - Panic message --- the human-readable error description
- Panic location --- file:line:column where
panic!()was called or the error occurred - Frame number --- sequential number starting from 0
- Symbol name --- demangled Rust function name with full module path
- File location --- source file and line number
RUST_BACKTRACE Levels
RUST_BACKTRACE=0--- no backtrace (default)RUST_BACKTRACE=1--- short backtrace (filters some internal frames)RUST_BACKTRACE=full--- complete backtrace including all runtime frames
Symbol Demangling
Rust function names in compiled binaries are mangled for uniqueness. The backtrace display demangles them to show readable names like my_app::process_items instead of _ZN6my_app13process_items17h.... When working with raw addresses or mangled symbols, tools like rustfilt can demangle them.
Common Rust Panics
index out of bounds--- array/slice access beyond lengthcalled Option::unwrap() on a None value--- unwrapping Nonecalled Result::unwrap() on an Err value--- unwrapping an errorattempt to divide by zero--- integer division by zero- Explicit
panic!()ortodo!()/unimplemented!()macros
Use Case
Rust panics appear in CLI tools, web servers (Actix, Axum, Rocket), embedded systems, WebAssembly applications, and system-level software. Since Rust's type system prevents many common errors at compile time, panics in production often indicate logic bugs like bounds violations or unwrap failures. Parsing the backtrace to quickly navigate past runtime internals to the application frame where the panic originated is essential for debugging Rust production issues.