From: Michael Jeanson Date: Tue, 17 May 2022 15:46:29 +0000 (-0400) Subject: fix: sched/tracing: Append prev_state to tp args instead (v5.18) X-Git-Tag: v2.12.14~2 X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=10ccd4327578d766737c25430104a21a4c7a4afa;p=lttng-modules.git fix: sched/tracing: Append prev_state to tp args instead (v5.18) See upstream commit : commit 9c2136be0878c88c53dea26943ce40bb03ad8d8d Author: Delyan Kratunov 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. Change-Id: Ife2ec88a8bea2743562590cbd357068d7773863f Signed-off-by: Michael Jeanson Signed-off-by: Mathieu Desnoyers --- diff --git a/instrumentation/events/lttng-module/sched.h b/instrumentation/events/lttng-module/sched.h index 49247286..ac91df12 100644 --- a/instrumentation/events/lttng-module/sched.h +++ b/instrumentation/events/lttng-module/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)