Re: [PATCH v5 3/9] x86: vdso: Expose sigreturn address on vdso to the kernel

On Mon, Aug 10, 2020 at 4:26 PM Gabriel Krisman Bertazi krisman@collabora.com wrote:

Syscall user redirection requires the signal trampoline code to not be captured, in order to support returning with a locked selector while avoiding recursion back into the signal handler. For ia-32, which has the trampoline in the vDSO, expose the entry points to the kernel, such that it can avoid dispatching syscalls from that region to userspace.

Almost looks good.

+int arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)

If you make that bool instead of int, feel free to add:

Acked-by: Andy Lutomirski luto@kernel.org