[all-commits] [llvm/llvm-project] e82344: [lldb][debugserver] Synchronize interrupt and resu...

[Jonas Devlieghere via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: e823449f66acb39ce5a11dde6283ffd11731fe6a
      https://github.com/llvm/llvm-project/commit/e823449f66acb39ce5a11dde6283ffd11731fe6a
  Author: Jonas Devlieghere <jonas at devlieghere.com>
  Date:   2025-03-13 (Thu, 13 Mar 2025)

  Changed paths:
    M lldb/tools/debugserver/source/MacOSX/MachProcess.h
    M lldb/tools/debugserver/source/MacOSX/MachProcess.mm

  Log Message:
  -----------
  [lldb][debugserver] Synchronize interrupt and resume signals (#131073)

This PR fixes a race condition in debugserver where the main thread
calls MachProcess::Interrupt, setting `m_sent_interrupt_signo` while the
exception monitoring thread is checking the value of the variable.

I was on the fence between introducing a new mutex and reusing the
existing exception mutex. With the notable exception of
MachProcess::Interrupt, all the other places where we were already
locking this mutex before accessing the variable. I renamed the mutex to
make it clear that it's now protecting more than the exception messages.

Jason, while investigating a real issue, had a suspicion there was race
condition related to interrupts and I was able to narrow it down by
building debugserver with TSan.



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