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 read that KASAN > supposes to be semi-production use ready, so the overhead is relatively low. > There is even a choice to have KASAN_SW_TAGS on arm64 to work better with > small > devices.
