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.
Change-Id: Ife2ec88a8bea2743562590cbd357068d7773863f
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>