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** Changed in: linux (Ubuntu)
       Status: New => Incomplete

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https://bugs.launchpad.net/bugs/1906447

Title:
  init_module may pin a lot of memory if given a bogus size

Status in linux package in Ubuntu:
  Incomplete
Status in stress-ng package in Ubuntu:
  New

Bug description:
  When running stress-ng sysinval stressor, I got a panic from an
  unrecoverable OOM.

  This happens because stress-ng will call init_module with a module
  length of INT_MAX and that will allocate that much memory with
  vmalloc, which is not accountable for the process. This memory is
  freed by using vfree right after that, but when you run 4 to 8
  stressors on a VM with ~8GiB of RAM, that might trigger OOM and there
  will be no way to recover, causing a panic.

  Using __GFP_RETRY_MAYFAIL for both init_module and kernel_read_file
  (called by finit_module), alleviates the problem, but does not solve
  it, as other allocators will trigger OOM.

  Module loading is an operation that is considered trusted, so it will
  be hard to do many changes in that path, so we might consider not
  stressing the system like that in our testing.

  Cascardo.

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