https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86486
Bug ID: 86486
Summary: GCC 8 stack clash protection on AArch64 is incomplete
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: other
Assignee: tnfchris at gcc dot gnu.org
Reporter: tnfchris at gcc dot gnu.org
Target Milestone: ---
Target: aarch64*-*-*
* Currently enabling stack clash will only provide protection from alloca and
not from prologue and epilogue code.
This is not sufficient to protect the stack from overflows.
* On AArch64 there are 2 supported guard page sizes: 64KB and 4KB.
The default guard page size is 64KB. The guard page size and probing
interval must always be identical. Assuming a 64KB guard page, functions can
allocate up to 63KB of stack and up to 1KB of outgoing arguments without
requiring any probes. The callee save registers (specifically LR) count as an
implicit probe.
Because of this the current implementation does not provide adequate stack
clash protection.
