When enabling stack use-after-free detection, we discovered that we read
the thread ID on the main thread while it is still set to 2^24-1.
This patch moves our call to AsanThread::Init() out of CreateAsanThread,
so that we can call SetCurrentThread first on the main thread.
Reviewed By: mcgrathr
Differential Revision: https://reviews.llvm.org/D89606
This reverts commit 0caad9fe44.
This reverts commit c96d0cceb6.
Causes linker errors which were not fixed by the subsequent commit
either:
/home/nikic/llvm-project/compiler-rt/lib/asan/asan_rtl.cpp:503: error: undefined reference to '__asan::InstallAtExitCheckLeaks()'
Fuchsia's system libraries are instrumented and use the lsan
allocator for internal purposes. So leak checking needs to run
after all atexit hooks and after the system libraries' internal
exit-time hooks. The <zircon/sanitizer.h> hook API calls the
__sanitizer_process_exit_hook function at exactly the right time.
Reviewed By: vitalybuka, phosek
Differential Revision: https://reviews.llvm.org/D86171
This CL allows asan allocator in fuchsia to decommit shadow memory
for memory allocated using mmap.
Big allocations in asan end up being allocated via `mmap` and freed with
`munmap`. However, when that memory is freed, asan returns the
corresponding shadow memory back to the OS via a call to
`ReleaseMemoryPagesToOs`.
In fuchsia, `ReleaseMemoryPagesToOs` is a no-op: to be able to free
memory back to the OS, you have to hold a handle to the vmo you want to
modify, which is tricky at the ReleaseMemoryPagesToOs level as that
function is not exclusively used for shadow memory.
The function `__sanitizer_fill_shadow` fills a given shadow memory range
with a specific value, and if that value is 0 (unpoison) and the memory
range is bigger than a threshold parameter, it will decommit that memory
if it is all zeroes.
This CL modifies the `FlushUnneededASanShadowMemory` function in
`asan_poisoning.cpp` to add a call to `__sanitizer_fill_shadow` with
value and threshold = 0. This way, all the unneeded shadow memory gets
returned back to the OS.
A test for this behavior can be found in fxrev.dev/391974
Differential Revision: https://reviews.llvm.org/D80355
Change-Id: Id6dd85693e78a222f0329d5b2201e0da753e01c0
Summary: This adds a customization point to support unpoisoning of signal alternate stacks on POSIX.
Reviewers: vitalybuka
Reviewed By: vitalybuka
Subscribers: #sanitizers
Tags: #sanitizers
Differential Revision: https://reviews.llvm.org/D81577
Roland McGrath