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Sun, 10 May 2020 04:47:50 +0000 Subject: Re: [PATCH bpf-next v4 00/21] bpf: implement bpf iterator for kernel data To: Alexei Starovoitov CC: Andrii Nakryiko , , Martin KaFai Lau , , Alexei Starovoitov , Daniel Borkmann , References: <20200509175859.2474608-1-yhs@fb.com> <20200510002731.ztx2inlfs65x2izc@ast-mbp> From: Yonghong Song Message-ID: Date: Sat, 9 May 2020 21:47:47 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 In-Reply-To: <20200510002731.ztx2inlfs65x2izc@ast-mbp> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-ClientProxiedBy: BY5PR16CA0035.namprd16.prod.outlook.com (2603:10b6:a03:1a0::48) To BYAPR15MB4088.namprd15.prod.outlook.com (2603:10b6:a02:c3::18) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from macbook-pro-52.local.dhcp.thefacebook.com (2620:10d:c090:400::5:e956) by BY5PR16CA0035.namprd16.prod.outlook.com (2603:10b6:a03:1a0::48) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2979.27 via Frontend Transport; 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X-MS-Exchange-AntiSpam-MessageData: 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 X-MS-Exchange-CrossTenant-Network-Message-Id: ca0822a3-1166-4d4a-c840-08d7f49d4a90 X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 May 2020 04:47:49.9436 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 8ae927fe-1255-47a7-a2af-5f3a069daaa2 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: z/Uamqo7X4Q8RGkCDAOZswzw/JfW3zrWvrLPGWFnrTWw+VDkIBS1db9MS/D/BfHB X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR15MB2565 X-OriginatorOrg: fb.com X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216,18.0.676 definitions=2020-05-10_01:2020-05-08,2020-05-10 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 phishscore=0 mlxlogscore=999 priorityscore=1501 impostorscore=0 bulkscore=0 adultscore=0 mlxscore=0 spamscore=0 malwarescore=0 clxscore=1015 suspectscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2005100042 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 5/9/20 5:27 PM, Alexei Starovoitov wrote: > On Sat, May 09, 2020 at 10:58:59AM -0700, Yonghong Song wrote: >> >> Changelog: >> v3 -> v4: >> - in bpf_seq_read(), if start() failed with an error, return that >> error to user space (Andrii) >> - in bpf_seq_printf(), if reading kernel memory failed for >> %s and %p{i,I}{4,6}, set buffer to empty string or address 0. >> Documented this behavior in uapi header (Andrii) >> - fix a few error handling issues for bpftool (Andrii) >> - A few other minor fixes and cosmetic changes. > > Looks great overall. Applied. > But few follow ups are necessary. > > The main gotcha is that new tests need llvm with the fix > https://urldefense.proofpoint.com/v2/url?u=https-3A__reviews.llvm.org_D78466&d=DwIBAg&c=5VD0RTtNlTh3ycd41b3MUw&r=DA8e1B5r073vIqRrFz7MRA&m=bCI_s36swhyaNaGGr3YQ0eQH9Lc-hpSGQy3u9fCRL9A&s=FLMd73HYbmZPnZrtCE9ntzg9e9eHOCioQbrt1w4sgWU&e= . > I think it was applied to llvm 10 branch already, > but please add selftests/bpf/README.rst and mention > that above llvm commit is necessary to successfully pass the tests. > Also mention the verifier error that folks will see when llvm is buggy. Okay. Will have a followup patch for this. > > Few other nits I noticed in relevant patches. >