mmap: Invalid argument

[AnaMazda]

after installing blacksmith successfully and setting up the hugepage to 1 GB I tested the following :
sudo ./blacksmith --dimm-id 1 --runtime-limit 120 --ranks 1
and i get this error message: mmap: Invalid argument
how can I check if my --dimm-id is valid or not? I think its the argument that creates this issue!
my OS : Linux ubuntu 5.11.0-27-generic 64-bit

[Patrick Jattke]

Hi @AnaMazda
See the README regarding the dimm-id parameter:

[...] we can run Blacksmith in fuzzing mode by passing a random DIMM ID (e.g., --dimm-id 1; only used internally for logging into stdout.log)

That said, dimm-id does not affect anything except for the logged output ing stdout.log.

I would suggest playing with the parameters we pass to mmap (see Memory.cpp):

• Try replacing MAP_SHARED by MAP_PRIVATE
• Try removing MAP_ANONYMOUS

Does anything of that make the program work? Do you get by chance any compilation errors/warnings?

[AnaMazda]

its compiled without any errors/warnings but the same issue still.

[Patrick Jattke]

Are you running Blacksmith on a native host (i.e., no VM or similar)? Are you compiling Blacksmith with gcc-8/g++-8?

I'm sorry but it's hard to tell what's the issue as I cannot reproduce it on any of our systems. Please consult Google or StackOverflow for general advice on mmap. A few more things you could try:

• You could post the synopsis section of man mmap so I can compare if anything of the interface changed (what I wouldn't expect though).
• Try to change the other call parameters of our call to mmap too:
  • What happens if you change the start_address in Memory.hpp? You could also try with just passing NULL to this parameter.
  • Does a smaller allocation (changing MEM_SIZE) succeed?
• You could try to add -ggdb3 to the targets bs and blacksmith in CMakeLists.txt and then run blacksmith via gdb, e.g.: sudo gdb --args ./blacksmith --dimm-id 0 --runtime-limit 120 --ranks 1

Please note that besides this issue you will also need to update the DRAM address function if you are not using an i7-8700K (probably, others of the same u-arch "Coffee Lake" would also work). Otherwise Blacksmith won't know how to address rows in order to hammer them.

[AnaMazda]

yes I'm using VMware !!

mmap synopsis

SYNOPSIS
       #include <sys/mman.h>

       void *mmap(void *addr, size_t length, int prot, int flags,
                  int fd, off_t offset);
       int munmap(void *addr, size_t length);

[Patrick Jattke]

We haven't tested Blacksmith in a VM yet. But you probably have the issue described in this SO post: invalid argument in mmap.

Feel free to make the required changes and submit a PR. We would be happy to incorporate the required changes. Thanks!

[AnaMazda]

thank you very much @pjattke for your time