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charset="us-ascii" Content-ID: MIME-Version: 1.0 X-OriginatorOrg: fb.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: SA1PR15MB5109.namprd15.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: 618dc060-9e9b-4126-a30d-08da14298607 X-MS-Exchange-CrossTenant-originalarrivaltime: 01 Apr 2022 21:49:40.0271 (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: um7uozFSNjIyd8m2Z/mtP9tbYU+9lfFzap3SuHSJ5VoG6nyjkoyxm2qqiDSyTou6E9pLATct3qPgCzhOe3gMPA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR15MB3222 X-Proofpoint-ORIG-GUID: 0GQ6-o7mhuB6x9cRNjp2Ri4zoW8yWCoj X-Proofpoint-GUID: 0GQ6-o7mhuB6x9cRNjp2Ri4zoW8yWCoj X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.850,Hydra:6.0.425,FMLib:17.11.64.514 definitions=2022-04-01_07,2022-03-31_01,2022-02-23_01 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org > On Mar 31, 2022, at 6:52 PM, Steven Rostedt wrote: > > On Thu, 31 Mar 2022 21:48:36 -0400 > Steven Rostedt wrote: > >>> Does this make sense to you? Did I miss something? >> >> I thought the BPF trampoline does: >> >> call bpf_trace_before_function >> call original_function + X86_PATCH_SIZE >> call bpf_trace_after_function >> >> Thus, the bpf direct trampoline calls the unpatched version of the >> function call making the live patch useless. Or is this not what it >> does? > > Or perhaps you are only talking about the part of bpf that does not > trace the end of a function? Yeah, we do call original_function + X86_PATCH_SIZE if there is fexit or fmod_ret programs. So this alone is not enough to make the two work together. :( Let me see how can we fix it... Thanks, Song