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charset="us-ascii" Content-ID: <925B8F3E9672B547882629D7D799A821@namprd15.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-CrossTenant-Network-Message-Id: e1b8f315-a794-40a4-507f-08d74db9d963 X-MS-Exchange-CrossTenant-originalarrivaltime: 10 Oct 2019 19:41:30.9876 (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: 5x3vNwH8eSEzh3WC+OZFBdf4iaGj8LzsrffTpyco+Kb3oVFwaCKxERIaYOYaYssB X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR15MB3389 X-OriginatorOrg: fb.com X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,1.0.8 definitions=2019-10-10_06:2019-10-10,2019-10-10 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 mlxlogscore=672 mlxscore=0 priorityscore=1501 impostorscore=0 adultscore=0 suspectscore=0 phishscore=0 spamscore=0 clxscore=1011 malwarescore=0 bulkscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1908290000 definitions=main-1910100163 X-FB-Internal: deliver Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Oct 10, 2019 at 08:17:49PM +0200, Jakub Sitnicki wrote: > It is currently not possible to detach the flow dissector program and > attach a new one in an atomic fashion, that is with a single syscall. > Attempts to do so will be met with EEXIST error. >=20 > This makes updates to flow dissector program hard. Traffic steering that > relies on BPF-powered flow dissection gets disrupted while old program ha= s > been already detached but the new one has not been attached yet. >=20 > There is also a window of opportunity to attach a flow dissector to a > non-root namespace while updating the root flow dissector, thus blocking > the update. >=20 > Lastly, the behavior is inconsistent with cgroup BPF programs, which can = be > replaced with a single bpf(BPF_PROG_ATTACH, ...) syscall without any > restrictions. >=20 > Allow attaching a new flow dissector program when another one is already > present with a restriction that it can't be the same program. Acked-by: Martin KaFai Lau