tree 9ee66272c7b9c9aec1b5ed182823c25d05d4a7a5
parent c29b49ee7dc9a9ee2526e45423232d36faf3468d
author Evgenii Stepanov <eugenis@google.com> 1634148502 -0700
committer Evgenii Stepanov <eugenis@google.com> 1634249894 +0000

Ignore PC/SP contents in SEGV_MTEAERR faults.

SEGV_MTEAERR (Async MTE fault) is delivered at an arbitrary point
after the actual fault. Register contents, including PC and SP, are
unrelated to the fault and can only confuse ART signal handlers.

To be more precise, SEGV_MTEAERR is delivered at the nearest kernel
entry after the invalid memory access. It is normally a system call, but
can also be a random process scheduling event.

I could not reproduce the problem locally, but it is apparently
possible to crash with "Check failed: found_virtual Didn't find oat
method index for virtual method:" if the garbage PC value passes all the
sanity checks in FaultManager::HandleFault, with a stack trace like
this:
  art::FindOatMethodFor
  art::ArtMethod::GetOatQuickMethodHeader
  art::FaultManager::IsInGeneratedCode
  art::FaultManager::HandleFault

Bug: 201492782
Test: none

Change-Id: I028067f1350574ea002f3e98a94babe2b10c2559