On 7/2/2025 6:27 AM, Kirill A. Shutemov wrote: >> >> Maybe I've misunderstood something: >> >> Is the underlying assumption here that #SS were previously only >> generated by userspace, but now they can also be generated by the >> kernel? And we want the kernel generated #SS to behave the same as the #GP? > > It can be generated by both kernel and userspace if RSP gets corrupted. > > So far, do_error_trap() did the trick, handling what has to be handled. > LASS requires a bit more, though. > Thank you for the information! The discussion in the other thread helped clarify my confusion about the new FRED specific fixup outside the LASS check. IIUC, for kernel generated #SS, the prior code in do_error_trap() would've done a few things such as notify_die() and cond_local_irq_enable() before calling die(). The new code now directly calls die_addr(). Are we changing the behavior for legacy kernel #SS? Also, why don't we need those calls for the new LASS #SS? I apologize if the questions seem too naive. I am finding the exception handling code a bit convoluted to understand. In general, I would suggest adding some code comments at least for the new code to help ignorant folks like me looking at this in the future.
