linux/samples/trace_events
Delyan Kratunov 9c2136be08 sched/tracing: Append prev_state to tp args instead
Commit fa2c3254d7 (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.

Fixes: fa2c3254d7 (sched/tracing: Don't re-read p->state when emitting sched_switch event, 2022-01-20)
Signed-off-by: Delyan Kratunov <delyank@fb.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lkml.kernel.org/r/c8a6930dfdd58a4a5755fc01732675472979732b.camel@fb.com
2022-05-12 00:37:11 +02:00
..
Makefile tracing: Add TRACE_CUSTOM_EVENT() macro 2022-03-11 11:49:24 -05:00
trace_custom_sched.c tracing: Add TRACE_CUSTOM_EVENT() macro 2022-03-11 11:49:24 -05:00
trace_custom_sched.h sched/tracing: Append prev_state to tp args instead 2022-05-12 00:37:11 +02:00
trace-events-sample.c samples/trace_event: Add '__rel_loc' using sample event 2021-12-06 15:37:22 -05:00
trace-events-sample.h tracing: Fix mismatched comment in __string_len 2022-01-13 16:23:05 -05:00