From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 68B76606A31E for ; Thu, 22 Oct 2026 10:27:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=msyIHhIt Received: by kanga.kvack.org (Postfix) id 15CD26B02CE; Thu, 22 Oct 2026 06:27:37 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 10ED26B02CF; Thu, 22 Oct 2026 06:27:37 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F3EE16B02D0; Thu, 22 Oct 2026 06:27:36 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id DBD6B6B02CE for ; Thu, 22 Oct 2026 06:27:36 -0400 (EDT) Received: from smtpin12.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 5E45D807C8 for ; Thu, 22 Oct 2026 10:27:36 +0000 (UTC) X-FDA: 85349885712.12.D8C9ED5 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf16.hostedemail.com (Postfix) with ESMTP id B72B6180008 for ; Thu, 22 Oct 2026 10:27:34 +0000 (UTC) Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=msyIHhIt; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf16.hostedemail.com: domain of ljs@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=ljs@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1792664854; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=5i/bEbxuGcfxHFgBF33/3ognHBBD4uli9jC93OptmuQ=; b=4IpNnjDovVHBb3VzJJ0/WS3a1XlJZcITLmBW+IudbWXCbjhnuY9CT+DEf+NUHaW0R9Gr1V 62RN5QlAu4m5OnKZW+WxwCIgQIg3QlFhvOeVK98FwWpeEjjAt0BBu6PGg0zTHVxFfT0KVH FArEx9o5vQDYZHi96ufohmiCufNyWTY= ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=msyIHhIt; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf16.hostedemail.com: domain of ljs@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=ljs@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1792664854; b=5cAOfoly4J296UFUbB+Sdh068MgGtkeO3+l3TXLPKqQ2nQVgZb/be1tXL6Ii1sESEjajrM y8DZMaiiQmr2tavbowRe1AzZMK5DcH9hJRbRODyYRHePdO2l+YBZAYk9Hy02759USKMEg9 /3AUEzBkrj7HRM9xJaDbUftQG74sCFU= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 4EAF760210; Thu, 22 Oct 2026 10:27:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CE27D1F000C2; Thu, 22 Oct 2026 10:27:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792664854; bh=5i/bEbxuGcfxHFgBF33/3ognHBBD4uli9jC93OptmuQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=msyIHhItxYKTq5jN2FoTYszCQmBbsyMEdqNkkA32J/6maH5H4ZVWFZHljKJHN60uv poiaB6oeeUhom1gG63UWLiobxbTQJb1J2RhsigElHV+uyio8Prca260ioYuHGqhlke ucHRvG1j50mu7u72qrDcWfTG3+OY7O6mBFrITHF9gXXs/2PRtMgunqARusriUEpKLv E/JglBMz12mGed1hL+yePPEbEc9ZYdk8CnmWTZU3PbA+KVM/7Y6Dk7SxIOOw//l/Pv WT6aAYyNGtcBkMSV7KYWSUZwZvjijOs+SFQyK6aZGtvxyxTgGUW5Y9mtHgSEZvCcJs D0eq7s/O/0WxQ== Date: Thu, 22 Oct 2026 11:27:28 +0100 From: "Lorenzo Stoakes (ARM)" To: Alexei Starovoitov Cc: Jiri Olsa , Daniel Borkmann , bpf@vger.kernel.org, Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , linux-mm@kvack.org, Andrew Morton , "Liam R. Howlett" , linux-kselftest@vger.kernel.org, Shuah Khan , John Fastabend Subject: Re: [RFC bpf-next 0/9] bpf: Add support to allocate user page Message-ID: References: <20261021195759.119421-1-jolsa@kernel.org> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: B72B6180008 X-Stat-Signature: w11or1uyur7wcesx7joxtqn5mdpsrqon X-Rspamd-Server: rspam06 X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=no autolearn_force=no version=4.0.1 X-Rspam-User: X-HE-Tag: 1792664854-56356 X-HE-Meta: U2FsdGVkX18XTaAlpDEpmAnA6ozTiftzarefhuWjGiDhklPzktc0gIzvyNroIoq6aGIfRfeSdiaGwUVVFuL9KHFrf5uoGA0+pScY+HQP2sfvnpcFmacFOIJTo51nXw+PjWVikLIC7deRWiYQjb2PuFcxEnBEWXaX6Oub8A9vS9K8OspbWTCFqqjiJOKwVzOVchbQC8Hrt92dZD1o0mcPXLS9UEYkH+CIhgbQJ+ILtoUPi73p0prvvpA1PJT3XbUKPI8CJ+tBPKOUdDd8YcTknuL8aYsH28fFtPyfKie6y4tr2qnj3xwIH42xl/nykJv1+vpA7t8DC3NSRt7LlqkHT3IOx/omvn/mmayZ3d7dav5oILszMDxxJsARaee0Q9Qbclj8Kak61YRXazY0iBGhIkd8fJUuRQTmMIpG6ob75njpjK0+dPAbQ0Kq5vJwipqd/CMuoVYJBnFQXmP07EJnAbyIfMWeyu/yNX2OP8yaN4YXMd0wC6ijyQHqq0UzOLAzB8PM8BmNciu+MmPdNaAtkZAAjW84XNBaj0OUXffObL/ZHaQxgberT3zBOq+8cZagcSNZByqbEOUTJyeSftXa16oQjcB+UEvIq3jQqIaXkvsKb8AYpx/5E7Zko7T5fu7kO4xKZp3PoHB/zWm9uQ+C3aNzIWzkR4x7owcPuBWI8c9vyNQ0Xa9ANjo+AjrIBbIV7NaOoNmVyuZt/SkB/MSzubQB3QFE1FdDgRxFwOm8+JViYF3RUbsXef1yk/Y4vPpGJe++DsJL9+VhUu0KP12K9m0k/5scHqVClArtVzetka9jKMiaSjTrTJZ4iLafI1aDuXlXkiSzTGZugVuZp/HvHmm/p1+Osm9fsb2PAVgrSKXOxulW+OL2N3bpbHkdD/MBoOC1RPy0kX851B30f9OhFPWPSdwfLASuops/DcWPJPgKm7jXW8KcXvlxA7IrYoUuqa+KTMhEN7LgW4iwPZG iGm8OzE/ mSSwqnIrGbtEEFRzT3iq6CnUcbur5nv+eVCYnJDsu1S0fX0HQV9ntJAHDhYvYwGM5PW04QzGmnyAUCJ8D3cwaWUshptBr3UyOwLpQj7RLbaGCc/VetNGEO104n7NLhD1q8QR2QEAXgBhdrAwctzus28t2d2YvlGT5Cb8N3PoV1OKO/EYuC3Amm/mbJm8eVTNDn9iB2IU3Uf2oECMA5lwYpZaLEubxOlq5+jb/Rp9VALLGhFI80dDunU+9DStZGn+Y6mJTg9W9BUBV5MGtVtT6VL/zetGXz9lJ3Xytf5Sihu/eLv3qAom6ICsc5cjRQ43H99KFoODlmVUn2RvLpvxRSoJxMRImQWOx+40H+FtpLSpoCII4kQVYcOW0/Q== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Wed, Oct 21, 2026 at 09:53:47PM +0000, Alexei Starovoitov wrote: > On Wed, Oct 21, 2026 at 12:57 PM Jiri Olsa wrote: > > hi, > > we have few use cases where having the ability to allocate normal > > or executable user space memory would help (like to replace function > > in live process or change environment variables) > > I think it's better to do what debuggers do: > vm_mmap() with the final prot and > access_process_vm(FOLL_FORCE | FOLL_WRITE), like PTRACE_POKETEXT, > to fill it. It faults the pages in, writes into r-x private mapping > and copy_to_user_page() takes care of icache. > Then no need for bpf_user_page_exec(), do_mprotect_pkey_locked(), > the marker, READ_IMPLIES_EXEC special case, get_user_pages(), etc. > No mm changes. OK thanks that addresses my concerns :) -- Cheers, Lorenzo