[PATCH] D40714: Correct atexit(3) support in MSan/NetBSD

[Kamil Rytarowski via Phabricator via llvm-commits]

krytarowski added inline comments.


================
Comment at: lib/msan/msan_interceptors.cc:1144
+
+    res = REAL(__cxa_atexit)((void (*)(void *a))MSanAtExitWrapper, 0, 0);
+    // Push AtExitCtx on the top of the stack of callback functions
----------------
vitalybuka wrote:
> krytarowski wrote:
> > vitalybuka wrote:
> > > do you need to call REAL(__cxa_atexit) under the lock?
> > Yes, as I'm pushing an item to the LIFO container.
> I see
>  there is possibility of MSanAtExitWrapper  immediately after REAL(__cxa_atexit) call
> so we don't want want MSanAtExitWrapper pass that mutex before we push
> 
The same algorithm is used in TSan. Blocking mutex is needed for hypothetical scenarios of executing atexit(3) callbacks and registering them concurrently. 


Repository:
  rL LLVM

https://reviews.llvm.org/D40714