From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B396E545DBF; Tue, 8 Sep 2026 13:51:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.15 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788875523; cv=none; b=bO0ttPLRuhfICot/WZSXqcnvcJSGpakXbgPayaQcPJxz4qhvoddyAmGbsEHrOQBFL+hPnHvBGSan67wYcfur7IdJs1KvV4r7pcde/jCZ7qs04JCDZWDsyunmdYm25M+cLlx13bss4PL/Yh6+Yjoj7U2Rq5g+rMnw5fhf/CE2IrE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788875523; c=relaxed/simple; bh=c8Gv/tOmnBsoRpMKP0BTnBqpL8Bhf2gTxJwPTe6abXg=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=M010ui3vZO1AIXJxaMoctqtXdt6gttzS9BFb2Dnmr4zSfG/gtHstME26dtcpqoYLI4pTH0JqQE56btz2oa7NyT5ovcoLRr6XRHjVqivmu+vx02nsoUCkNNh6MO92hhcPJp2FwYCpFtmi3gbSmbwfct7jBWa7Jd1VhIeReK6xHBE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; dkim=pass (1024-bit key) header.d=goodmis.org header.i=@goodmis.org header.b=uTc1rGyi; arc=none smtp.client-ip=216.40.44.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=goodmis.org header.i=@goodmis.org header.b="uTc1rGyi" Received: from omf13.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 297A31C27D3; Tue, 8 Sep 2026 13:51:55 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf13.hostedemail.com (Postfix) with ESMTPA id BF43420012; Tue, 8 Sep 2026 13:51:39 +0000 (UTC) Date: Tue, 8 Sep 2026 09:52:53 -0400 From: Steven Rostedt To: "Jose Fernandez (Anthropic)" Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Nathan Chancellor , Nicolas Schier , Nick Desaulniers , Bill Wendling , Justin Stitt , Catalin Marinas , Will Deacon , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Puranjay Mohan , Xu Kuohai , Ard Biesheuvel , Ilias Apalodimas , Miguel Ojeda , Boqun Feng , Gary Guo , =?UTF-8?B?QmrDtnJu?= Roy Baron , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Daniel Almeida , Tamir Duberstein , Alexandre Courbot , Onur =?UTF-8?B?w5Z6a2Fu?= , Sami Tolvanen , Kees Cook , Leon Hwang , Ihor Solodrai , Josh Poimboeuf , live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, llvm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, bpf@vger.kernel.org, linux-efi@vger.kernel.org, rust-for-linux@vger.kernel.org, Ben Cressey , "Florent Revest (Anthropic)" Subject: Re: [PATCH RFC 1/8] ftrace: Let ftrace_call_adjust() reject a patch site Message-ID: <20260908095253.520c278c@gandalf.local.home> In-Reply-To: References: <20260904-b4-arm64-callops-kcfi-v1-0-ce6687739b0c@linux.dev> <20260904-b4-arm64-callops-kcfi-v1-1-ce6687739b0c@linux.dev> <20260904084728.6d2ebcc8@gandalf.local.home> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: x457bex6yki4ewxmaioc5ood1sdccp73 X-Rspamd-Server: rspamout08 X-Rspamd-Queue-Id: BF43420012 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX18nR2NzFrPVTBxdKw6aYNAKXDfxBb2FKIM= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=goodmis.org; h=date:from:to:cc:subject:message-id:in-reply-to:references:mime-version:content-type:content-transfer-encoding; s=dkim1; bh=zmEISpUYs3PxDYsmwRf2tNZx1Ic66nQ4OS2YYg6VWuk=; b=uTc1rGyiax3d1heQBZvkqpESgAHTDt6puNzDb1kcaIw4IkVtTy8A1ipxHVxbFEoTotD5HI2HsR4MrblNpcB2tBhZCY5+By0G9i36l82d2hxFXEU+61IX5LsNnB8IYnbFlV+Hdk8lzxWxarrR31+5z6ELIXFNLi1siI+bPwO90hs= X-HE-Tag: 1788875499-703192 X-HE-Meta: U2FsdGVkX19G2BzycxCMNywV55nFSuOsSuiCbrC27AdqLgblO/sjNWn8yFEVA1Pp4o54M56CAWLIIQPWiVbjNfHhKlkV7l9KH/m9cY30zHeFrqCV8VhxxkqgYRPQd0XdnDR29QpQjYtYZgEHDCk6F4UR4PhSZraMLTC0xijKFy1vc0KkipbPR7rWejQrGl0csG0VWcKwTFPmYo+8Mz/gKTw5i6SQwge1PHx9dHxhXncKI6vPabGOBRl5yQN6P/57/0gb/tGzPJdwg8IvwUXMxizGUE136mn9rXBG5BXLbaHmWF3w9OZI7xiwx2sAB2Pm On Sun, 6 Sep 2026 20:40:59 +0000 "Jose Fernandez (Anthropic)" wrote: > Will add one in v2, thanks. > > Today arm64 returns 0 only for a mis-aligned patch site. But patch 4 of > this series replaces that check with two: the two NOPs to patch must be > there, and the ops pointer must fit in the prefix NOPs (which also > catches a mis-aligned site). How about this to cover the series? > > /* The architecture may return 0 to reject a patch site */ That comment is fine. I didn't really like the specifying of mis-alignment as it did appear to be too specific, and could change. -- Steve > > Happy to name the mis-aligned case in patch 1 and extend the comment > in patch 4 if you prefer that.