From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EA1C3CA1002 for ; Sat, 6 Sep 2025 13:25:31 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 25A1F6B0005; Sat, 6 Sep 2025 09:25:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2323A6B0006; Sat, 6 Sep 2025 09:25:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 126908E0002; Sat, 6 Sep 2025 09:25:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id EFEA66B0005 for ; Sat, 6 Sep 2025 09:25:30 -0400 (EDT) Received: from smtpin25.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 65F4013A984 for ; Sat, 6 Sep 2025 13:25:30 +0000 (UTC) X-FDA: 83858897220.25.E997CDD Received: from mail-wm1-f53.google.com (mail-wm1-f53.google.com [209.85.128.53]) by imf25.hostedemail.com (Postfix) with ESMTP id 7C38FA0010 for ; Sat, 6 Sep 2025 13:25:28 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=S6SNW2MC; spf=pass (imf25.hostedemail.com: domain of andreyknvl@gmail.com designates 209.85.128.53 as permitted sender) smtp.mailfrom=andreyknvl@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1757165128; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=VE+Mx/TU7aQIVb363hbvW+WQvMnqT6BMcQeprM6OFYE=; b=8g/Ld7/Ths6lFBWOyVlg4V99IctQTSQdMRhGCC7x+mXbYGTqmZCHFtkmiOraSMUbszn2E3 uAAngbR/cUbpC9sugKRqPIzKVLcPSFDF+eX1wKzIz+3e6LzYCOIIolmC5krJSnbigs1fuk olwfic5vjSP+lElnvGQH3r1zedXV4bI= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=S6SNW2MC; spf=pass (imf25.hostedemail.com: domain of andreyknvl@gmail.com designates 209.85.128.53 as permitted sender) smtp.mailfrom=andreyknvl@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1757165128; a=rsa-sha256; cv=none; b=VnCDKM0+7DFXDlkYvSUoPVXvMpvKPU0dVKGjWZNIr1gAMIDV8YEh1n/CqWI1oy/76Ap5Tz hHkZQMRLBD7hrs4OdcD0PJCQM/HL1kYLODHVNvW2rQjVZkIVnmuokGj4PHrf5Y0mxXJElm zxVfJKpTNM0HX81+P29IbQVxncDbdI0= Received: by mail-wm1-f53.google.com with SMTP id 5b1f17b1804b1-45dde353b47so1487215e9.3 for ; Sat, 06 Sep 2025 06:25:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1757165127; x=1757769927; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=VE+Mx/TU7aQIVb363hbvW+WQvMnqT6BMcQeprM6OFYE=; b=S6SNW2MCQSux5/4P8r9UDy+I3QR5N2iBzh9+OQX51ZB8XBNpASf4OKq3iGHZa5qjFl +wbqeRwUUaG1X0WPuDYn+XOLN7izYzJaW65AIwRR42Ntis18ywfJf/RarCowQKuqh486 nJ/15zveCx8/Kx0l41BrGkeGuNXSXeYTARPwmLDPXCKM797uwPWeB2pJkId2GQGGWGPC lnHJlpoYfDbdEwz9o8uIBfBPmwzbttmFjvaBIZpBAc9DuhSyJjBK3ruPHMPES4qoXn5o dkZJ22UP/l45rW6KrIt5Nr2OILyeC//oYiZA+E2PKNcqKWHZhopITKeyKMCrLDrc+ixk 6p4g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757165127; x=1757769927; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=VE+Mx/TU7aQIVb363hbvW+WQvMnqT6BMcQeprM6OFYE=; b=FqvyW8luTf6FdkITbXgnxFpQWr00nlztiy+fZX/L/vSerKUeEiL7WtG8Pc/jl52c1P oYDIVHlHVArsI0+vIJzvEmbxCR44N4oEOm86X/rfY9d8W9fYe1D7rkSUUUU8s7dNMk9Z P71eVFTEE1Dwg5psiiYWw9XqftSGa59dt2I/aikQ17VBK9uMqLYJJVanXNcYoIC/I4xr CurSYHRS4i7EdcX0UIMqTV+U/sswBaz5VQIhtidU2l+fVKvHQdJ8FErlxV7dZuihdg58 83q3f65q76R59wuHBkwERsjBbkE04631lV3CpU1DPjKvqBculp9WxkIrIxpN6xGDeoDQ aO1g== X-Forwarded-Encrypted: i=1; AJvYcCXkW7OIWdiqmbsQnUjNPd5DfoQJ9FgTfUe55imG8mHEnSn1y+C2izy8+7GFP5Fc3QBoOJXpkzVFPg==@kvack.org X-Gm-Message-State: AOJu0Yyp2zWBUA7JFBiK6gfjdPTyl0oxWIKn4VgQh1xfEDNwVHHy5MpR P1sa0SyoraLvcdn/VpZVJl945TwNZaL1VoTpddd6V2aOC7PrWPOUOjkwogBXvKdoz3vlqyqVCtG zNQuNQ/W8jtHFyxXxRi4FaH6Qr3n6VfA= X-Gm-Gg: ASbGncv8AJLbBgsz1ghM1SBioUHAdgYORZRWJd8sfS8arSsKVz8LRZ821Pb9ayLSL57 p1uN0/20mqmuPShjQ4o3z4Zdo0aT8m5cBkpkV/VxygHI0KjpbXgluWGW385Xm+5Utihy/j0HGQH ufmhyIUMB48tiitn6//yuamr+8fSs5nJ0F8gKvVBp2LU36R9GrTzP/tW2fElCCcJ2o6nVI+ZdjM CIoUBRn X-Google-Smtp-Source: AGHT+IH7xxFltspr8zCiYexkZxI5yiQn/I8vOs80sqSulDOmiRjBylXmYFVNrCaFsedsn3UnPzIuoip5fBxmKpv09wE= X-Received: by 2002:a5d:5887:0:b0:3d1:6d7a:ab24 with SMTP id ffacd0b85a97d-3e641a6095cmr1198571f8f.17.1757165126529; Sat, 06 Sep 2025 06:25:26 -0700 (PDT) MIME-Version: 1.0 References: <20250820053459.164825-1-bhe@redhat.com> <75a2eb31-3636-44d4-b2c9-3a24646499a4@gmail.com> In-Reply-To: From: Andrey Konovalov Date: Sat, 6 Sep 2025 15:25:15 +0200 X-Gm-Features: AS18NWDtWolEoXZVKCJMBulXUlUwGez_rwjXq9tKdDHHBjrrgE8FIXbdfmCaUgk Message-ID: Subject: Re: [PATCH v3 00/12] mm/kasan: make kasan=on|off work for all three modes To: Baoquan He Cc: glider@google.com, dvyukov@google.com, elver@google.com, linux-mm@kvack.org, vincenzo.frascino@arm.com, akpm@linux-foundation.org, kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, sj@kernel.org, lorenzo.stoakes@oracle.com, christophe.leroy@csgroup.eu, Andrey Ryabinin , snovitoll@gmail.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 7C38FA0010 X-Stat-Signature: 8aafqedhsjhmow13y67b717guwqomd3d X-Rspam-User: X-HE-Tag: 1757165128-892199 X-HE-Meta: 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 Y/t0A8oA 8wCX6s43PflrJVVlWL1PrMeXv97WFHPoUDnj6t0Hkrh0ISg1lbtYBOBbL2vl+FwmsjTjE6EdqJLXVhDsFhWXQ+1nS+pPf6TqLCkz1yL5oZbwozzolHV2vnmwoPrqvia83DzBJUOrAXENJh0Q/GbqXlcfCPKXKBZA1aLE8SnYj4Om6AUuiO1yB1jONIPOOm9JPRER6SFKHJMxt4Y4s+D4Sb3owMpnTm6SD76GKOegdX/JOE6rqNwbc4VkIJRJNQ3FTh47DvgR6mY84cj5eqDSpGfNxjdesKel8zLrQn0LC3FX4SBUSneW/oQjWCdrrdEnkcujJE2QFKDETgMk0ribgFC5+ZplyMRcRB8E4oMVTfYGPrl/qW8a55aax2D2HJYHFhxBX0rFakQ5fGW1UcCFlkMvszuFB8J9ilVxut4TsqsN4HhM2mqrXo0IkhqaAUb7pFw8D 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: List-Subscribe: List-Unsubscribe: On Fri, Sep 5, 2025 at 10:34=E2=80=AFPM Andrey Konovalov wrote: > > Baoquan, I'd be in favor of implementing kasan.vmalloc=3Doff instead of > kasan=3Doff. This seems to both (almost) solve the RAM overhead problem > you're having (AFAIU) and also seems like a useful feature on its own > (similar to CONFIG_KASAN_VMALLOC=3Dn but via command-line). The patches > to support kasan.vmalloc=3Doff should also be orthogonal to the > Sabyrzhan's series. > > If you feel strongly that the ~1/8th RAM overhead (coming from the > physmap shadow and the slab redzones) is still unacceptable for your > use case (noting that the performance overhead (and the constant > silent detection of false-positive bugs) would still be there), I > think you can proceed with your series (unless someone else is > against). Hm, just realized that kasan.vmalloc=3Doff would probably break if CONFIG_VMAP_STACK is enabled: read-only shadow for vmalloc =3D> read-only shadow for stacks =3D> stack instrumentation will try writing into read-only shadow and crash. So I wonder if there's a way to avoid the lazy vmap freeing to deal with the RAM overhead.