llvm-project/compiler-rt
Kostya Kortchinsky 040c211bc4 [scudo] Fix improper TSD init after TLS destructors are called
Summary:
Some of glibc's own thread local data is destroyed after a user's thread local
destructors are called, via __libc_thread_freeres. This might involve calling
free, as is the case for strerror_thread_freeres.
If there is no prior heap operation in the thread, this free would end up
initializing some thread specific data that would never be destroyed properly
(as user's pthread destructors have already been called), while still being
deallocated when the TLS goes away. As a result, a program could SEGV, usually
in __sanitizer::AllocatorGlobalStats::Unregister, where one of the doubly linked
list links would refer to a now unmapped memory area.

To prevent this from happening, we will not do a full initialization from the
deallocation path. This means that the fallback cache & quarantine will be used
if no other heap operation has been called, and we effectively prevent the TSD
being initialized and never destroyed. The TSD will be fully initialized for all
other paths.

In the event of a thread doing only frees and nothing else, a TSD would never
be initialized for that thread, but this situation is unlikely and we can live
with that.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D37697

llvm-svn: 312939
2017-09-11 19:59:40 +00:00
..
cmake [cmake] Work around more -Wunused-driver-argument warnings 2017-09-07 01:36:47 +00:00
docs [sanitizers] Make it possible to XFAIL on the effective target, not just the default. 2016-08-09 11:50:53 +00:00
include Prevent DCE on __lsan_is_turned_off and re-enable test case 2017-09-08 19:43:53 +00:00
lib [scudo] Fix improper TSD init after TLS destructors are called 2017-09-11 19:59:40 +00:00
test [scudo] Fix improper TSD init after TLS destructors are called 2017-09-11 19:59:40 +00:00
unittests Add missing import 2017-04-07 01:24:48 +00:00
www Update references to new lists.llvm.org mailing lists. 2015-08-05 03:58:00 +00:00
.arcconfig Upgrade all the .arcconfigs to https. 2016-07-14 13:15:37 +00:00
.gitignore Add .pyc files to .gitignore to compiler-rt 2017-07-24 21:51:12 +00:00
CMakeLists.txt Move libFuzzer to compiler_rt. 2017-08-21 23:25:50 +00:00
CODE_OWNERS.TXT [sanitizers] remove earthdok@ from owners 2016-05-18 18:52:18 +00:00
CREDITS.TXT
LICENSE.TXT Update copyright year to 2016. 2016-03-30 22:38:50 +00:00
README.txt

README.txt

Compiler-RT
================================

This directory and its subdirectories contain source code for the compiler
support routines.

Compiler-RT is open source software. You may freely distribute it under the
terms of the license agreement found in LICENSE.txt.

================================