[PATCH] D93731: scudo: Support memory tagging in the secondary allocator.

[Mitch Phillips via Phabricator via llvm-commits]

hctim added inline comments.


================
Comment at: compiler-rt/lib/scudo/standalone/combined.h:833
   void disableMemoryTagging() {
-    if (allocatorSupportsMemoryTagging<Params>())
+    initThreadMaybe();
+    if (allocatorSupportsMemoryTagging<Params>()) {
----------------
Yeah, this unfortunately means that some of the sizeclasses get mapped as PROT_MTE even when MTE is disabled. Maybe we should pull this change out of this patch and follow up separately, as it sounds like we might need to pull the MTE options out of the primary options bitset so it doesn't get clobbered at init-time.

```
$ adb shell process/with/no/mte
$ adb shell cat /proc/<pid>/smaps | egrep 'VmFlags.*mt' -B23
7ca588f000-7ca58cf000 rw-p 00000000 00:00 0                              [anon:scudo:primary]
VmFlags: rd wr mr mw me ac mt
7cd588c000-7cd58cc000 rw-p 00000000 00:00 0                              [anon:scudo:primary]
VmFlags: rd wr mr mw me ac mt
```


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D93731/new/

https://reviews.llvm.org/D93731