From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-215.mta1.migadu.com [95.215.58.215]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B4BDB44AB64 for ; Thu, 24 Sep 2026 22:36:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.215 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790289395; cv=none; b=lXBaHtCVuHbRy0ld6BudhsJWHKN/EFDry9fzaTuodCatBh/iHCkL7djAhWXRpQLGqvr4uYZN7vyc0ByVh3dr37DnRfnoFhWzkibu+ustCx6svnzfxKKjfXZfVGBnD5G5nxPT/DhoCiUZmPHPexxwDPstjRe+YhRAlKXcI1zQEgM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790289395; c=relaxed/simple; bh=6tASAd8sUDq5Ftr41lemiI/nY6tO72VqXbeQ3Os+o5Q=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=QzbzFufuqFsaXts62t1q/6yKTLrpXkGCqSv7C4fh2MInzSa5fD3I1q7S6CKlNnSC0jBHKQycmqxbjq8wlZ4AiqHkM1cTczo6UOVGmeZwblyebVxyKSGaGr01sbCACuimBcOrLEKote2zbVkAPtxgd25uLohQn14hSGluKZ6VrQk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=B41dXUOT; arc=none smtp.client-ip=95.215.58.215 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="B41dXUOT" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=6tASAd8sUDq5Ftr41lemiI/nY6tO72VqXbeQ3Os+o5Q=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1790289391; v=1; x=1790894191; b=B41dXUOThndc05ma5tGSSoiI86LIS0CyB2WJBO9fEj/lP4Ztem5KgGOpxCzkYEfZE43IArqE bJial81CjDJBPlwt3GyBjQ8dC8IkZsN9Tr1yJHTFPB5ZfHFADwr0WomNwe/gIjlEbpn7CzSYPrO oQmAJnjiF4aRHimuno12lBbA= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id e5a9a7017ca58495; Thu, 24 Sep 2026 22:36:31 +0000 X-Mizu-Trace-ID: e5a9a7017ca58495 X-Migadu-Flow: FLOW_OUT From: "Jose Fernandez (Anthropic)" Date: Thu, 24 Sep 2026 22:35:46 +0000 Subject: [PATCH v2 2/9] ftrace: Let ftrace_call_adjust() reject a patch site Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260924-b4-arm64-callops-kcfi-v2-2-587865b6d991@linux.dev> References: <20260924-b4-arm64-callops-kcfi-v2-0-587865b6d991@linux.dev> In-Reply-To: <20260924-b4-arm64-callops-kcfi-v2-0-587865b6d991@linux.dev> To: Steven Rostedt , 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?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Daniel Almeida , Tamir Duberstein , Alexandre Courbot , =?utf-8?q?Onur_=C3=96zkan?= , Sami Tolvanen , Kees Cook Cc: 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)" , "Jose Fernandez (Anthropic)" X-Mailer: b4 0.15.2 When ftrace_call_adjust() returns 0 for a patch site, ftrace_process_locs() does not skip the site. The NULL test runs before the adjustment since commit 6eeca746fa5f ("ftrace: Test mcount_loc addr before calling ftrace_call_addr()"), so the 0 is stored as the record's ip and ftrace_init_nop() later hits the BUG_ON() in arm64's patch_map(). Test the adjusted address too and count the site as skipped. Reviewed-by: Ben Cressey Reviewed-by: Florent Revest (Anthropic) Assisted-by: LLM Signed-off-by: Jose Fernandez (Anthropic) --- kernel/trace/ftrace.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 2cc2d41353c10..fa541d3e8784a 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -7676,6 +7676,11 @@ static int ftrace_process_locs(struct module *mod, } addr = ftrace_call_adjust(addr); + /* The architecture may return 0 to reject a patch site */ + if (!addr) { + skipped++; + continue; + } end_offset = (pg->index+1) * sizeof(pg->records[0]); if (end_offset > PAGE_SIZE << pg->order) { -- 2.52.0