[PATCH] D115057: [msan] Don't block SIGSYS in ScopedBlockSignals

[Hans Wennborg via Phabricator via llvm-commits]

hans created this revision.
hans added reviewers: vitalybuka, eugenis.
hans requested review of this revision.
Herald added a project: Sanitizers.
Herald added a subscriber: Sanitizers.

Seccomp-BPF-sandboxed processes rely on being able to process SIGSYS signals.

This un-breaks Chrome after D113328 <https://reviews.llvm.org/D113328>.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D115057

Files:
  compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp


Index: compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
===================================================================
--- compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
+++ compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
@@ -162,6 +162,12 @@
   // on any thread, setuid call hangs.
   // See test/sanitizer_common/TestCases/Linux/setuid.c.
   internal_sigdelset(&set, 33);
+#  endif
+#  if SANITIZER_LINUX
+  // Seccomp-BPF-sandboxed processes rely on SIGSYS to handle trapped syscalls.
+  // If this signal is blocked, such calls cannot be handled and the process may
+  // hang.
+  internal_sigdelset(&set, 31);
 #  endif
   SetSigProcMask(&set, &saved_);
   if (copy)


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