| From 9c5b8de32b5745f3ff31079c02da64595e101bee Mon Sep 17 00:00:00 2001 |
| From: Michael Jeanson <mjeanson@efficios.com> |
| Date: Tue, 17 May 2022 11:46:29 -0400 |
| Subject: [PATCH] fix: sched/tracing: Append prev_state to tp args instead |
| (v5.18) |
| |
| See upstream commit : |
| |
| commit 9c2136be0878c88c53dea26943ce40bb03ad8d8d |
| Author: Delyan Kratunov <delyank@fb.com> |
| Date: Wed May 11 18:28:36 2022 +0000 |
| |
| sched/tracing: Append prev_state to tp args instead |
| |
| Commit fa2c3254d7cf (sched/tracing: Don't re-read p->state when emitting |
| sched_switch event, 2022-01-20) added a new prev_state argument to the |
| sched_switch tracepoint, before the prev task_struct pointer. |
| |
| This reordering of arguments broke BPF programs that use the raw |
| tracepoint (e.g. tp_btf programs). The type of the second argument has |
| changed and existing programs that assume a task_struct* argument |
| (e.g. for bpf_task_storage access) will now fail to verify. |
| |
| If we instead append the new argument to the end, all existing programs |
| would continue to work and can conditionally extract the prev_state |
| argument on supported kernel versions. |
| |
| |
| Upstream-Status: Backport |
| |
| Change-Id: Ife2ec88a8bea2743562590cbd357068d7773863f |
| Signed-off-by: Michael Jeanson <mjeanson@efficios.com> |
| Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| --- |
| include/instrumentation/events/sched.h | 6 +++--- |
| 1 file changed, 3 insertions(+), 3 deletions(-) |
| |
| diff --git a/include/instrumentation/events/sched.h b/include/instrumentation/events/sched.h |
| index 339bec94..c1c3df15 100644 |
| --- a/include/instrumentation/events/sched.h |
| +++ b/include/instrumentation/events/sched.h |
| @@ -356,11 +356,11 @@ LTTNG_TRACEPOINT_EVENT_INSTANCE(sched_wakeup_template, sched_wakeup_new, |
| LTTNG_TRACEPOINT_EVENT(sched_switch, |
| |
| TP_PROTO(bool preempt, |
| - unsigned int prev_state, |
| struct task_struct *prev, |
| - struct task_struct *next), |
| + struct task_struct *next, |
| + unsigned int prev_state), |
| |
| - TP_ARGS(preempt, prev_state, prev, next), |
| + TP_ARGS(preempt, prev, next, prev_state), |
| |
| TP_FIELDS( |
| ctf_array_text(char, prev_comm, prev->comm, TASK_COMM_LEN) |
| -- |
| 2.19.1 |
| |