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Delyan Kratunov
9c2136be08
Commitfa2c3254d7(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 <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Acked-by: Steven Rostedt (Google) <[email protected]> Link: https://lkml.kernel.org/r/[email protected]