[compiler-rt][scudo] Check for failing prctl call
A bunch of MTE tests like ./ScudoUnitTest-aarch64-Test/MemtagTest.StoreTags
can fail on aarch64-linux if the kernel doesn't support the tagged address ABI. It looks like
the call to prctl(PR_GET_TAGGED_ADDR_CTRL, 0, 0, 0, 0) can return -1, which
casted to an unsigned int and masked will return a value not equal to
PR_MTE_TCF_NONE, meaning systemDetectsMemoryTagFaultsTestOnly can return an incorrect value.
This updates the check to account for a failing prctl call.
Differential Revision: https://reviews.llvm.org/D110888
GitOrigin-RevId: 993555beb8ff33aa35773af01cb3821ae45e6e39
diff --git a/memtag.h b/memtag.h
index c48e228..8097b77 100644
--- a/memtag.h
+++ b/memtag.h
@@ -91,9 +91,10 @@
#ifndef PR_MTE_TCF_MASK
#define PR_MTE_TCF_MASK (3UL << PR_MTE_TCF_SHIFT)
#endif
- return (static_cast<unsigned long>(
- prctl(PR_GET_TAGGED_ADDR_CTRL, 0, 0, 0, 0)) &
- PR_MTE_TCF_MASK) != PR_MTE_TCF_NONE;
+ int res = prctl(PR_GET_TAGGED_ADDR_CTRL, 0, 0, 0, 0);
+ if (res == -1)
+ return false;
+ return (static_cast<unsigned long>(res) & PR_MTE_TCF_MASK) != PR_MTE_TCF_NONE;
}
inline void enableSystemMemoryTaggingTestOnly() {
