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dkim=pass header.d=gmail.com header.s=20210112 header.b="I3v95p/E"; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf16.hostedemail.com: domain of andreyknvl@gmail.com designates 209.85.166.51 as permitted sender) smtp.mailfrom=andreyknvl@gmail.com X-Stat-Signature: bkibjpepcdnbaoki6kdfa6rptajwg8a4 X-HE-Tag: 1654800026-479461 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: Hi Catalin, On Thu, Jun 9, 2022 at 8:32 PM Catalin Marinas wrote: > > > This would make __GFP_SKIP_KASAN_UNPOISON do two logically unrelated > > things: skip setting memory tags and reset page tags. This seems > > weird. > > Not entirely weird, it depends on how you look at it. After allocation, > you expect the accesses to page_address() to work, irrespective of the > GFP flags. __kasan_unpoison_pages() ensures that the page->flags match > the written tag without a new GFP flag to set the page->flags. If you > skip the unpoisoning something should reset the page->flags tag to > ensure an accessible page_address(). I find it weirder that you need > another GFP flag to pretty much say 'give me an accessible page'. Hm, this makes sense. > As above, my preference would be to avoid a new flag, just wire this up > to __GFP_SKIP_KASAN_UNPOISON. But if you do want fine-grained control, I > can add the above. OK, let's do as you suggest. Thanks!