[all-commits] [llvm/llvm-project] 77e906: [scudo][standalone] Implement TSD registry disabling

[Kostya Kortchinsky via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 77e906ac78abda8bb2bdcc223e4b5c457f08bb04
      https://github.com/llvm/llvm-project/commit/77e906ac78abda8bb2bdcc223e4b5c457f08bb04
  Author: Kostya Kortchinsky <kostyak at google.com>
  Date:   2019-12-20 (Fri, 20 Dec 2019)

  Changed paths:
    M compiler-rt/lib/scudo/standalone/combined.h
    M compiler-rt/lib/scudo/standalone/flags.cpp
    M compiler-rt/lib/scudo/standalone/tests/wrappers_c_test.cpp
    M compiler-rt/lib/scudo/standalone/tsd_exclusive.h
    M compiler-rt/lib/scudo/standalone/tsd_shared.h

  Log Message:
  -----------
  [scudo][standalone] Implement TSD registry disabling

Summary:
In order to implement `malloc_{enable|disable}` we were just disabling
(or really locking) the Primary and the Secondary. That meant that
allocations could still be serviced from the TSD as long as the cache
wouldn't have to be filled from the Primary.

This wasn't working out for Android tests, so this change implements
registry disabling (eg: locking) so that `getTSDAndLock` doesn't
return a TSD if the allocator is disabled. This also means that the
Primary doesn't have to be disabled in this situation.

For the Shared Registry, we loop through all the TSDs and lock them.
For the Exclusive Registry, we add a `Disabled` boolean to the Registry
that forces `getTSDAndLock` to use the Fallback TSD instead of the
thread local one. Disabling the Registry is then done by locking the
Fallback TSD and setting the boolean in question (I don't think this
needed an atomic variable but I might be wrong).

I clang-formatted the whole thing as usual hence the couple of extra
whiteline changes in this CL.

Reviewers: cferris, pcc, hctim, morehouse, eugenis

Subscribers: jfb, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D71719