[PATCH] D60593: [GwpAsan] Introduce GWP-ASan.

[Vlad Tsyrklevich via Phabricator via llvm-commits]

vlad.tsyrklevich added inline comments.


================
Comment at: compiler-rt/lib/gwp_asan/guarded_pool_allocator.h:67
+    case 1:
+      NextSampleCounter = (Random::getRandomUnsigned64() % SampleRate) + 1;
+      return true;
----------------
vlad.tsyrklevich wrote:
> vlad.tsyrklevich wrote:
> > Random::getRandomUnsigned64() % SampleRate means we are sampling more often than the actual sampling rate. This should be % (SampleRate * 2), or, even better, sample from a geometric distribution
> Woops, seems I made the same mistake in http://crrev.com/c/1400050
Actually I take that back. After reading it again that code uses a complicated sampling mechanism that does sample 1/N, the reason I chose it is so that we did not undersample the first SampleRate allocations as this scheme will. If it's possible to use the standard library I'd just replace it with a geometric distribution from the beginning if you can.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D60593/new/

https://reviews.llvm.org/D60593