On Tue, Jun 23, 2026 at 4:43 AM Peter Zijlstra [off-list ref] wrote:

On Mon, Jun 22, 2026 at 02:31:08PM -0400, David Windsor wrote:

quoted

Uprobe CALL emulation updates the normal user stack, but not the CET user
shadow stack. The subsequent RET then sees a stale shadow stack entry and
raises #CP.

Update the relative CALL emulation and XOL CALL fixup paths to keep the
shadow stack in sync.

Fixes: 488af8ea7131 ("x86/shstk: Wire in shadow stack interface")

I can confirm this patch fixes the included test case, so yay for that.

However, should this not be:

Fixes: 1713b63a07a2 ("x86/shstk: Make return uprobe work with shadow stack")

?

Hmm, this commit appears to only be concerned with the uretprobe case?