On Wed, Jul 19, 2023 at 04:33:26PM -0400, Joe Lawrence wrote: > On 7/19/23 11:21, Petr Mladek wrote: > > On Fri 2023-06-23 18:55:29, Brian Gerst wrote: > >> When kCFI is enabled, special handling is needed for the indirect call > >> to the kernel thread function. Rewrite the ret_from_fork() function in > >> C so that the compiler can properly handle the indirect call. > > > > This patch broke livepatching. Kthreads never have a reliable stack. > > It works when I revert it. > > > > Just curious -- did the selftests catch this anywhere? I'm not 100% > clear on what trees / frequency they all run, so maybe Petr you found > this by code inspection or other means? I suspect Petr ran the selftests himself, they're fairly easy to run (once you figure out the magic incantation) and insta fail. I'm not sure the robots consistently run this stuff -- I've had these patches exposed to 0day for weeks...
