On Thu, Sep 15, 2022 at 05:59:56PM -0600, Yu Zhao wrote: > I think this is a manifest of the lockdep warning I reported a couple > of weeks ago: > https://lore.kernel.org/r/CAOUHufaPshtKrTWOz7T7QFYUNVGFm0JBjvM700Nhf9qEL9b3EQ@xxxxxxxxxxxxxx/ That would certainly match the symptoms. Turning vmap_lock into an NMI-safe lock would be bad. I don't even know if we have primitives for that (it's not like you can disable an NMI ...) I don't quite have time to write a patch right now. Perhaps something like: struct vmap_area *find_vmap_area_nmi(unsigned long addr) { struct vmap_area *va; if (spin_trylock(&vmap_area_lock)) return NULL; va = __find_vmap_area(addr, &vmap_area_root); spin_unlock(&vmap_area_lock); return va; } and then call find_vmap_area_nmi() in check_heap_object(). I may have the polarity of the return value of spin_trylock() incorrect.
