MemoryMap fails on ARM

[geraldstanje]

Hi,

I ported this c app (http://ideone.com/AbImAr) to rust but face an issue with MemoryMap.

The rust app is cross compiled on my ubuntu linux for the ARM:

# file /sbin/init
/sbin/init: ELF 32-bit LSB  shared object, ARM, EABI5 version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.32, BuildID[sha1]=289a0061854bb8d2f7ed8286c0a18aa1207141a5, stripped

Rust was built from source according to https://github.com/japaric/ruststrap/blob/master/1-how-to-cross-compile.md

The rust app is built using cargo:

$ rustc --version
rustc 1.0.0-dev (a59de37e9 2015-05-13) (built 2015-5-14)

$ cargo build --target=arm-unkown-linux-gnuabihf

The rust app crashes without any error and cuts off my ssh connection to the device...
what happens could be:
in best case the kernel crashes, in worst case a disk buffer is overwritten and face a silent filesystem corruption...

Here the code code of the rust app (which crashes when executing the unsafe part):
http://is.gd/PT0cwM

Gdb output:
why does it report "Cannot access memory"? Can i trust this info to be correct?

let mmap = MemoryMap::new(size, mmap_opts).unwrap();
(gdb) next
42      let data = mmap.data();
(gdb) print mmap
$1 = {data = 0xb5c00000 <error: Cannot access memory at address 0xb5c00000>, len = 8388608, kind = {{RUST$ENUM$DISR = MapFile, __0 = 0x0}, {
      RUST$ENUM$DISR = MapFile}}}

Strace for the rust app (to get the strace, the unsafe part of the code was disabled):
http://ideone.com/hNIYMw

[klutzy]

MemoryMap is no longer a part of standard library now. According to crates.io info, you should ask https://github.com/rbranson/rust-mmap.

[geraldstanje]

ok. i posted it there: rbranson/rust-mmap#4 ...can you comment?