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| author | Delyan Kratunov <delyank@fb.com> | 2022-05-11 18:28:36 +0000 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-05-12 00:37:11 +0200 |
| commit | 9c2136be0878c88c53dea26943ce40bb03ad8d8d (patch) | |
| tree | 63ea6e07f82cc650db9a4d14d87f4b82df34a9c6 /include/trace/events/sched.h | |
| parent | c5eb0a61238dd6faf37f58c9ce61c9980aaffd7a (diff) | |
| download | lwn-9c2136be0878c88c53dea26943ce40bb03ad8d8d.tar.gz lwn-9c2136be0878c88c53dea26943ce40bb03ad8d8d.zip | |
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.
Fixes: fa2c3254d7cf (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
Diffstat (limited to 'include/trace/events/sched.h')
| -rw-r--r-- | include/trace/events/sched.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h index 65e786756321..fbb99a61f714 100644 --- a/include/trace/events/sched.h +++ b/include/trace/events/sched.h @@ -222,11 +222,11 @@ static inline long __trace_sched_switch_state(bool preempt, TRACE_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_STRUCT__entry( __array( char, prev_comm, TASK_COMM_LEN ) |