On Fri, Sep 04, 2026 at 12:25:59PM +0100, Harry Yoo wrote: > I don't understand why v3 of this patchset suddenly implements > hardening for kfree() and usercopy to handle ERR_PTR(). > > The address range for 'zero or NULL PTR' range and ERR_PTR() do not > overlap. The bugfixes and hardening patches are irrelevant. > It should be a separate series? > > Also usercopy.c changes go through the hardening tree, slub.c and > slub_kunit.c changes go through the slab tree, and LKDTM has its own > tree. Patch 3 and 5 touch files across multiple trees, which can be > avoided. >
I added the ERR_PTR changes after Kees raised handling that range in the v2 review [1]. The two topics also came up together in the 2014 [2] and 2019 [3] discussions; in the latter, Jann suggested a separate warning-and-return check [4]. I wanted to broaden the discussion and see whether considering both together might suggest a better approach. I agree that the resulting implementations are independent. I'll send v4 with the ZERO_SIZE_PTR alignment, exact-match and zero-size KUnit patches only, and pursue the ERR_PTR work separately. I'll split that work along the SLUB, usercopy and LKDTM boundaries you pointed out. [1] https://lore.kernel.org/r/202608111716.0FA9DB17@keescook/ [2] https://lore.kernel.org/r/[email protected]/ [3] https://lore.kernel.org/r/[email protected]/ [4] https://lore.kernel.org/r/cag48ez05qvn6_gq2tbrra1a_dwqoassyubusu5ymwxx-gqm...@mail.gmail.com/ Thanks, Karl
