On Mon, Aug 11, 2025 at 09:10:07AM -0500, Jeremy Linton wrote: > The arm64 probe simulation doesn't currently have logic in place > to deal with GCS and this results in core dumps if probes are inserted > at control flow locations. Fix-up bl, blr and ret to manipulate the > shadow stack as needed. > > While we manipulate and validate the shadow stack correctly, the > hardware provides additional security by only allowing GCS operations > against pages which are marked to support GCS. For writing there is > gcssttr() which enforces this, but there isn't an equivalent for > reading. This means that uprobe users should be aware that probing on > control flow instructions which require reading the shadow stack (ex: > ret) offers lower security guarantees than what is achieved without > the uprobe active. > > Signed-off-by: Jeremy Linton <[email protected]>
Reviewed-by: Catalin Marinas <[email protected]>
