On Tue, 24 Apr 2018, Michal Hocko wrote: > On Mon 23-04-18 20:06:16, Mikulas Patocka wrote: > [...] > > @@ -404,6 +405,12 @@ void *kvmalloc_node(size_t size, gfp_t f > > */ > > WARN_ON_ONCE((flags & GFP_KERNEL) != GFP_KERNEL); > > > > +#ifdef CONFIG_DEBUG_SG > > + /* Catch bugs when the caller uses DMA API on the result of kvmalloc. */ > > + if (!(prandom_u32_max(2) & 1)) > > + goto do_vmalloc; > > +#endif > > I really do not think there is anything DEBUG_SG specific here. Why you > simply do not follow should_failslab path or even reuse the function? CONFIG_DEBUG_SG is enabled by default in RHEL and Fedora debug kernel (if you don't like CONFIG_DEBUG_SG, pick any other option that is enabled there). Fail-injection framework is if off by default and it must be explicitly enabled and configured by the user - and most users won't enable it. Mikulas > > + > > /* > > * We want to attempt a large physically contiguous block first because > > * it is less likely to fragment multiple larger blocks and therefore > > @@ -427,6 +434,9 @@ void *kvmalloc_node(size_t size, gfp_t f > > if (ret || size <= PAGE_SIZE) > > return ret; > > > > +#ifdef CONFIG_DEBUG_SG > > +do_vmalloc: > > +#endif > > return __vmalloc_node_flags_caller(size, node, flags, > > __builtin_return_address(0)); > > } > > -- > Michal Hocko > SUSE Labs >
