From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (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 E865C584944; Tue, 8 Sep 2026 16:33:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.158.5 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788885219; cv=none; b=SIRlE9THHIDIXAu6zf1qeKCKux3nx5+cAjiHRFPUTp7Z6Rzn9kJ6OIQkvp8fbI5HBruu0ofdSTMcvY2X0dQiGUWnOWBRrW5FGzSRi9sjXBa+dykc6amnKxU8yL/OOmUtmyqE3UerNIlum6OUtA+wi6kltOv2m6ijtsMq/8x6Yi8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788885219; c=relaxed/simple; bh=eXZm9UMGLWjpU5UOxf0lRTOdluSEUuqO/VzrnFVWtI4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=uvlS1e2QoM2I3MwdjNv2EdvfBtQtoIFA/KcJhGVjCR9PktmsUCNtjtpygtXs25YxlhK0qU/DTtm+3eU2ZSQQY8jCYuupoVLUQhGZHmtDtYqV3kyUAWfL2+FR9IW70saodjjn/zzE1VrwNRTXTCkbYh8UrFj8mraAPf/sKw5d/M0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=f02g5x/K; arc=none smtp.client-ip=148.163.158.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="f02g5x/K" Received: from pps.filterd (m0353725.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 688F1ek1080692; Tue, 8 Sep 2026 16:33:18 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=pp1; bh=yC9WRO c5hKeZDWBapMIIHj+0R4ybqRQjVgDPeWwSkqQ=; b=f02g5x/KEiVHJksP37Zlly hAd9kb0pmyCe6/XMUbxRAlhBbkELzLYyPFtuDTMKypNTpKWTDrQ/Fqkw2/2PuWso 3DavRhIMHqoXB9CRsJ2Rfl/6etEKz9F+mzgYlKbPPAPL706tHdREpbHcs62nUf8B 5IJ8d5NbqR6GSoXr2zFxFxCN/nhOw0ex2fIuZxoCTJblN6oCjlVLrQHFvgJCRVnV Iobq9GfRoBt1KhZbeVjdTe8wNpunUiCmGbu5vbHPuGQ6DFDB6fNfKaNSr64Qzktu 66bZ5o7DXJEVw2MgYVKktvfzkeGri9RC0ryQqaUmcuo+lPjfeebJe1SyFPUVzgBQ == Received: from ppma22.wdc07v.mail.ibm.com (5c.69.3da9.ip4.static.sl-reverse.com [169.61.105.92]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4ggbjrr5e7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 08 Sep 2026 16:33:18 +0000 (GMT) Received: from pps.filterd (ppma22.wdc07v.mail.ibm.com [127.0.0.1]) by ppma22.wdc07v.mail.ibm.com (8.18.1.7/8.18.1.7) with ESMTP id 688GQEQZ031291; Tue, 8 Sep 2026 16:33:17 GMT Received: from smtprelay06.fra02v.mail.ibm.com ([9.218.2.230]) by ppma22.wdc07v.mail.ibm.com (PPS) with ESMTPS id 4ggwsw56g7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 08 Sep 2026 16:33:17 +0000 (GMT) Received: from smtpav03.fra02v.mail.ibm.com (smtpav03.fra02v.mail.ibm.com [10.20.54.102]) by smtprelay06.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 688GXDFg43909500 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 8 Sep 2026 16:33:13 GMT Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 7765820043; Tue, 8 Sep 2026 16:33:13 +0000 (GMT) Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1ADFA2004B; Tue, 8 Sep 2026 16:33:08 +0000 (GMT) Received: from [9.61.253.97] (unknown [9.61.253.97]) by smtpav03.fra02v.mail.ibm.com (Postfix) with ESMTPS; Tue, 8 Sep 2026 16:33:07 +0000 (GMT) Message-ID: <738ca597-abc4-4867-963f-ed1a55aa4a54@linux.ibm.com> Date: Tue, 8 Sep 2026 22:03:04 +0530 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v13 6/8] selftests/bpf: Fix powerpc JIT disassembly failure To: Saket Kumar Bhaskar , bpf@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Cc: hbathini@linux.ibm.com, maddy@linux.ibm.com, ast@kernel.org, andrii@kernel.org, daniel@iogearbox.net, shuah@kernel.org, linux-kselftest@vger.kernel.org, stable@vger.kernel.org, venkat88@linux.ibm.com, yeswanth@linux.ibm.com References: <6034e8b7dc0c6954be35b6735a9b04b35903ed5f.1788154635.git.skb99@linux.ibm.com> Content-Language: en-US From: R Nageswara Sastry In-Reply-To: <6034e8b7dc0c6954be35b6735a9b04b35903ed5f.1788154635.git.skb99@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=E7T9Y6dl c=1 sm=1 tr=0 ts=6aa038ce cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=IkcTkHD0fZMA:10 a=VdqzKS8jKosA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VnNF1IyMAAAA:8 a=EX4WfZDNQFKdhq70EaoA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Info: AW1haW4tMjYwOTA4MDE3OCBTYWx0ZWRfX+azGlUoiqaGn BFB/WKFI+D1wYowYXu0RTl7uVA/nlcu/2/u93stWa6qaw0IYAQjTCQz0pVs2wEBtSU7Vaqmp2Ko nRCcgZ985TFs0fa1uBSb5uYn4rKFWe0= X-Proofpoint-ORIG-GUID: 2CliXsQskbKrP9XBtDnZ-c4NweA505uY X-Proofpoint-GUID: 2CliXsQskbKrP9XBtDnZ-c4NweA505uY X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTA4MDE3OCBTYWx0ZWRfXy4j+QQXc8O22 hIYT/yEvD/gY/igpIsfKRNI6k+AOlPVFpPsJd+VrHWy+d5gceeZsXVJnoxulfx6pvSS9LWYcUkq iHmIBkZeCas5Qzolhndv7euyFGQyqpw4oSKX0guYIV9vQIKtHbkjkMUrenRA5OJsDzF8gRHTwwr GjLBTi7A9Yoo+swvWfFe/OfScnmRZhexna86sOvS8ZWTpA0UgkQLoktZYcBhDbkBxBcVZXjU1n2 PBc/zTYXYTahnXVOzwNVBrcOEgHKCsrn2je5SASjJ8sdneE6k1zfSvvGtkHa1W7bmojFt2JKayD mp4Z9VD/Cg6IoZwHHwGPYF1HIb+AR5xxji0wvLvZV2wlfE1RtOwIBmTG84Ec4gd42euwcJT2Y/m 8/e4JDim9dhe9+apu/VBL4lZmDYW09TFnX2oKVQYaRsHvff7CWlMKNuYtoYKKdIfMkiQvQaKHEQ FTDifjPBRDXL18ZilGw== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-09-08_03,2026-09-08_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 phishscore=0 spamscore=0 suspectscore=0 priorityscore=1501 bulkscore=0 impostorscore=0 malwarescore=0 lowpriorityscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2609080178 On 31.08.2026 12:46 PM, Saket Kumar Bhaskar wrote: > From: Abhishek Dubey > > Ensure that the trampoline stubs JITed at the tail of the > epilogue do not expose the dummy trampoline address stored > in the last 8 bytes(64-bit) and last 4 bytes(32-bit) > to the disassembly flow. Prevent the disassembler from > ingesting this memory address, as it may occasionally decode > into a seemingly valid but incorrect instruction. Fix this > issue by truncating the last 8/4 bytes from JITed buffers > before supplying them for disassembly. > > Signed-off-by: Abhishek Dubey > Signed-off-by: Saket Kumar Bhaskar > Tested-by: Yeswanth Krishna Tellakula > Reviewed-by: Hari Bathini Tested-by: R Nageswara Sastry System: ppc64le LPAR (IBM POWER), Linux 7.3-rc2 > --- > .../selftests/bpf/jit_disasm_helpers.c | 25 ++++++++++++++++++- > 1 file changed, 24 insertions(+), 1 deletion(-) > > diff --git a/tools/testing/selftests/bpf/jit_disasm_helpers.c b/tools/testing/selftests/bpf/jit_disasm_helpers.c > index 3558fe10e28c..b291d934dd1a 100644 > --- a/tools/testing/selftests/bpf/jit_disasm_helpers.c > +++ b/tools/testing/selftests/bpf/jit_disasm_helpers.c > @@ -179,9 +179,11 @@ int get_jited_program_text(int fd, char *text, size_t text_sz) > struct bpf_prog_info info = {}; > __u32 info_len = sizeof(info); > __u32 jited_funcs, len, pc; > + __u32 trunc_len = 0, disasm_len; > __u32 *func_lens = NULL; > FILE *text_out = NULL; > uint8_t *image = NULL; > + char *triple = NULL; > int i, err = 0; > > if (!llvm_initialized) { > @@ -225,9 +227,30 @@ int get_jited_program_text(int fd, char *text, size_t text_sz) > if (!ASSERT_OK(err, "bpf_prog_get_info_by_fd #2")) > goto out; > > + /* > + * last 8 bytes contains dummy_trampoline address in JIT > + * output on 64-bit and last 4 bytes on 32-bit powerpc, > + * which can't disassemble to a valid instruction. > + */ > + triple = LLVMGetDefaultTargetTriple(); > + if (triple) { > + if (strstr(triple, "powerpc64") || strstr(triple, "ppc64")) > + trunc_len = 8; > + else if (strstr(triple, "powerpc") || strstr(triple, "ppc")) > + trunc_len = 4; > + LLVMDisposeMessage(triple); > + } > + > for (pc = 0, i = 0; i < jited_funcs; ++i) { > fprintf(text_out, "func #%d:\n", i); > - disasm_one_func(text_out, image + pc, func_lens[i]); > + > + /* > + * Disabled JIT have zero func_lens, hence underflow > + */ > + disasm_len = func_lens[i] > trunc_len ? > + func_lens[i] - trunc_len : 0; > + disasm_one_func(text_out, image + pc, disasm_len); > + > fprintf(text_out, "\n"); > pc += func_lens[i]; > } -- Thanks and Regards R.Nageswara Sastry