On Mon, Sep 30, 2019 at 11:39:34PM +0200, Vlastimil Babka wrote: > On 9/30/19 2:49 PM, Qian Cai wrote: > >> --- a/Documentation/admin-guide/kernel-parameters.txt > >> +++ b/Documentation/admin-guide/kernel-parameters.txt > >> @@ -3237,6 +3237,14 @@ > >> we can turn it on. > >> on: enable the feature > >> > >> + page_owner_free= > >> + [KNL] When enabled together with page_owner, store also > >> + the stack of who frees a page, for error page dump > >> + purposes. This is also implicitly enabled by > >> + debug_pagealloc=on or KASAN, so only page_owner=on is > >> + sufficient in those cases. > >> + on: enable the feature > >> + > > > > If users are willing to set page_owner=on, what prevent them from enabling KASAN > > as well? That way, we don't need this additional parameter. > > Well, my use case is shipping production kernels with CONFIG_PAGE_OWNER > and CONFIG_DEBUG_PAGEALLOC enabled, and instructing users to boot-time > enable only for troubleshooting a crash or memory leak, without a need > to install a debug kernel. Things like static keys and page_ext > allocations makes this possible without CPU and memory overhead when not > boot-time enabled. I don't know too much about KASAN internals, but I > assume it's not possible to use it that way on production kernels yet? I don't know about production, but QEMU (without KVM acceleration) is painfully slow if KASAN is enabled. -- Kirill A. Shutemov
