Now that page aliasing for x64 has landed, we don't need to worry about
passing tagged pointers to libc, and thus D98875 removed it.
Unfortunately, we still test on aarch64 devices that don't have the
kernel tagged address ABI (https://reviews.llvm.org/D98875#2649269).
All the memory that we pass to the kernel in these tests is from global
variables. Instead of having architecture-specific untagging mechanisms
for this memory, let's just not tag the globals.
Reviewed By: eugenis, morehouse
Differential Revision: https://reviews.llvm.org/D101121
Userspace page aliasing allows us to use middle pointer bits for tags
without untagging them before syscalls or accesses. This should enable
easier experimentation with HWASan on x86_64 platforms.
Currently stack, global, and secondary heap tagging are unsupported.
Only primary heap allocations get tagged.
Note that aliasing mode will not work properly in the presence of
fork(), since heap memory will be shared between the parent and child
processes. This mode is non-ideal; we expect Intel LAM to enable full
HWASan support on x86_64 in the future.
Reviewed By: vitalybuka, eugenis
Differential Revision: https://reviews.llvm.org/D98875
Userspace page aliasing allows us to use middle pointer bits for tags
without untagging them before syscalls or accesses. This should enable
easier experimentation with HWASan on x86_64 platforms.
Currently stack, global, and secondary heap tagging are unsupported.
Only primary heap allocations get tagged.
Note that aliasing mode will not work properly in the presence of
fork(), since heap memory will be shared between the parent and child
processes. This mode is non-ideal; we expect Intel LAM to enable full
HWASan support on x86_64 in the future.
Reviewed By: vitalybuka, eugenis
Differential Revision: https://reviews.llvm.org/D98875
HwasanThreadList::DontNeedThread clobbers Thread::next_,
Breaking the freelist. As a result, only the top of the freelist ever
gets reused, and the rest of it is lost.
Since the Thread object with its associated ring buffer is only 8Kb, this is
typically only noticable in long running processes, such as fuzzers.
Fix the problem by switching from an intrusive linked list to a vector.
Differential Revision: https://reviews.llvm.org/D91392
HwasanThreadList::DontNeedThread clobbers Thread::next_, breaking the
freelist. As a result, only the top of the freelist ever gets reused,
and the rest of it is lost.
Since the Thread object its associated ring buffer is only 8Kb, this is
typically only noticable in long running processes, such as fuzzers.
Fix the problem by switching from an intrusive linked list to a vector.
Differential Revision: https://reviews.llvm.org/D91208
