From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f43.google.com (mail-ej1-f43.google.com [209.85.218.43]) (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 DD96F27FB25 for ; Sat, 20 Sep 2025 22:17:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.43 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758406672; cv=none; b=QDTAuVZNx4iKhKA8AciWfhO8ys/IakJmcly6pLF2PHJfC18EPbkg481GneCN771pttDtTHrIa+8jjb7p9YyYIozQUbHryvdbDA6c0auwWMwOyzLDMFJHqVJVSEt8ZbeNAtpA+IPOASIqE+6KSDI2jQU+Hy+0sjzKN4C3jntIstQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758406672; c=relaxed/simple; bh=96dxx70d/BFqImcMeVoXOM+8YDlRuIcpQzt1VmBfil0=; h=From:Date:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=QZQirGpnRXGAUBZwEpD5+1eE5o41iiUlcqY9CAL6YClE5CFvvOthtdgYVORyQE4mABwL47Asq9ZRyPuW4aU9rEopKW0zunzbJaSaCy88ne7uFU9M0Ge+XJvZ3zXKgxNgXdes7b2jW11h26PjVgvFTSnWePpkX77/uvDyjIx3ePg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=TsKS8oV0; arc=none smtp.client-ip=209.85.218.43 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="TsKS8oV0" Received: by mail-ej1-f43.google.com with SMTP id a640c23a62f3a-afcb7ae6ed0so458888766b.3 for ; Sat, 20 Sep 2025 15:17:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1758406669; x=1759011469; darn=vger.kernel.org; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:date:from:from:to :cc:subject:date:message-id:reply-to; bh=+HgtdynmY0igjvNZnpu91IhlMXMmcHk6gD8131LsDf8=; b=TsKS8oV0Ec0JLnc+mKCN31OZwyskRpLNrWsMigl1/dOchWeXQssOd/lTV4qyybo6s1 JsqpSWMGeSJcsO+VYB9ZWS7kuT7UpSLnyCJEwMDbp8gjgvmq8Xq/9EM0ZtS7pbpT/4Sp AFSmjvITqXq803uTKWjAMela4Vpt8rWFBSLfEMmIG+7Cm4lx5QW7g6j5Rxb+Vi+bKbqJ bnPWZpRnR6OjzM6SkJ1VnYTpVwstiNe+G7vR2cii07FYmvv7IPN+FAl138+pLVXb1u6T OyKkY5uGxnElZy6Ht6eBZOCYr5m8bIHai4bXZq1WcdlFkT81xM8nWAIXwOR3SMua7NHo zZYg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1758406669; x=1759011469; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:date:from :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=+HgtdynmY0igjvNZnpu91IhlMXMmcHk6gD8131LsDf8=; b=NHKgLUP4HTKPeZ5o0haHU3RT5k8IR0emCHl7qduY9pBh8eyR+uNZ3B4asnx3+i4cuW Hq0FYHW0mUcNWuem7S3BIRrTH8KztNwX0hiNQNRajBOio/cJq2BInC62UBBiB1+h0yEc TEiQ9+AKGC0Y7SPBaf6HoELdBjz1lh2FbvB9vPmz/j+Xn0zjzwS+gV1H+n6qqEFKmAy9 23r4pvmnX9lozK7+7SQhmhEB9bermGoM66dmZxp01zxCpRmeOnRdNF9C4Iw6NYkqFpKP eWZafhIpBSjqA16PDChcg9QW53y+UvDj4CAtEP4iCb/BvDv+NJyILamjSyAKzHLLu54K LEgg== X-Forwarded-Encrypted: i=1; AJvYcCUosvl8XVkuRFNXNQz1HSKAFLuLHTb7gZ+y8HktNLDkBaYVE85EJbZiHOi3SZ+9bjyv+YvUBrOh6Gn9U2FG1PcNsI0=@vger.kernel.org X-Gm-Message-State: AOJu0YxFrhKY8wsPWs7uFhF9Hjtxqyj/IdqMUeee5EJdxJhPjmFfYP+q c/W3InKRL5qaxVW1wom1ana8zt+hsX41FoQF6MVCNo26fHnbZaJwZx0V X-Gm-Gg: ASbGncundaPGbblwquxpL6dAc25fgMaWHbZoYg4E3mV/SNtg3JrrkksmFZ3Tds0jtJZ M03ok0nGRK1DiL/bxu9pIoS2Lxh6u1NxQsFzN/WRZy+lRnpj4VyBdLElN9ztRw4dY9olUu4NKuF cOTAvppLK9SBpTYQrzGiNKnVUHNLSfpOjBjbc+nDZGlNfk2VL5dQtbuef23zt3RA8168PwOo85k E1OS7+TGmafHKI9duR2+e+NfU0SS1tCpikyfmeIMuWPom7B/rPy0HslpRElxQI8a3FWzDDcAXSY arOx7syU9YbZihFe2pof3Y5pkUIMRqDTV9hynxQ/gpU0U8kmY2boJS7/QrEcWf75fZaIS/hSeza egcU1Q/z5jflrVu44So8J1vBtlu+exVz4lBFCXIiCEjk= X-Google-Smtp-Source: AGHT+IHuYXbv1MwgeFhgGHEnoMk2vC63tOuKqEj+eah5xHgaTZ82uYXktvX8jVWZFLF7LGFrAO/urA== X-Received: by 2002:a17:907:7245:b0:afe:7027:56f9 with SMTP id a640c23a62f3a-b24ef58d811mr815980866b.17.1758406668905; Sat, 20 Sep 2025 15:17:48 -0700 (PDT) Received: from krava (37-188-197-68.red.o2.cz. [37.188.197.68]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b2864cd8376sm218759666b.80.2025.09.20.15.17.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 20 Sep 2025 15:17:48 -0700 (PDT) From: Jiri Olsa X-Google-Original-From: Jiri Olsa Date: Sun, 21 Sep 2025 00:17:42 +0200 To: Alexei Starovoitov , Will Deacon Cc: Feng Yang , Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Martin KaFai Lau , Eduard , Song Liu , Yonghong Song , KP Singh , Stanislav Fomichev , Hao Luo , bpf , LKML , linux-trace-kernel , Masami Hiramatsu Subject: Re: [BUG] Failed to obtain stack trace via bpf_get_stackid on ARM64 architecture Message-ID: References: <20250919071902.554223-1-yangfeng59949@163.com> 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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Fri, Sep 19, 2025 at 07:56:20PM -0700, Alexei Starovoitov wrote: > On Fri, Sep 19, 2025 at 12:19 AM Feng Yang wrote: > > > > When I use bpf_program__attach_kprobe_multi_opts to hook a BPF program that contains the bpf_get_stackid function on the arm64 architecture, > > I find that the stack trace cannot be obtained. The trace->nr in __bpf_get_stackid is 0, and the function returns -EFAULT. > > > > For example: > > diff --git a/tools/testing/selftests/bpf/progs/kprobe_multi.c b/tools/testing/selftests/bpf/progs/kprobe_multi.c > > index 9e1ca8e34913..844fa88cdc4c 100644 > > --- a/tools/testing/selftests/bpf/progs/kprobe_multi.c > > +++ b/tools/testing/selftests/bpf/progs/kprobe_multi.c > > @@ -36,6 +36,15 @@ __u64 kretprobe_test6_result = 0; > > __u64 kretprobe_test7_result = 0; > > __u64 kretprobe_test8_result = 0; > > > > +typedef __u64 stack_trace_t[2]; > > + > > +struct { > > + __uint(type, BPF_MAP_TYPE_STACK_TRACE); > > + __uint(max_entries, 1024); > > + __type(key, __u32); > > + __type(value, stack_trace_t); > > +} stacks SEC(".maps"); > > + > > static void kprobe_multi_check(void *ctx, bool is_return) > > { > > if (bpf_get_current_pid_tgid() >> 32 != pid) > > @@ -100,7 +109,9 @@ int test_kretprobe(struct pt_regs *ctx) > > SEC("kprobe.multi") > > int test_kprobe_manual(struct pt_regs *ctx) > > { > > + int id = bpf_get_stackid(ctx, &stacks, 0); > > ftrace_partial_regs() supposed to work on x86 and arm64, > but since multi-kprobe is the only user... > I suspect the arm64 implementation wasn't really tested. > Or maybe there is some other issue. > > Masami, Jiri, > thoughts? hi, I did quick test for kprobe multi and I can reproduce the issue on arm64 with ci: https://github.com/kernel-patches/bpf/pull/9809 but can't really tell what's missing on arm side.. cc-ing Will thanks, jirka