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dkim=pass header.d=oracle.com header.s=corp-2021-07-09 header.b=ber6VrGt; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=TjeKl5h5; spf=none (imf31.hostedemail.com: domain of william.kucharski@oracle.com has no SPF policy when checking 205.220.177.32) smtp.mailfrom=william.kucharski@oracle.com; dmarc=pass (policy=none) header.from=oracle.com X-HE-Tag: 1639428831-321350 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Thanks, good explanation. > On Dec 13, 2021, at 1:47 PM, Kees Cook wrote: >=20 > On Mon, Dec 13, 2021 at 08:27:42PM +0000, Matthew Wilcox wrote: >> On Mon, Dec 13, 2021 at 07:18:57PM +0000, William Kucharski wrote: >>> I like these, but a quick question: >>>=20 >>> Since the usercopy_abort() calls are all because the offset exceeds the= page >>> size, is there a reason why you don't specifically state that via the d= etail >>> parameter rather than just supply a NULL pointer? >>=20 >> Hmm ... I'd defer to Kees on this, because I'm not familiar with >> usercopy_abort() usage, but the only places which use the detail >> parameter today are slab/slub, which use it to pass the name of >> the slab. I think the user is supposed to infer that we overran the >> end of the page based on the offset & length values. >=20 > I agree that leaving it NULL is best here. The "detail" is really about > adding more information about which thing it was, which for slab makes > sense, but most other stuff there isn't really anything to quickly > distinguish one from another (i.e. vmap is all vmap). >=20 > --=20 > Kees Cook