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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 <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
96 lines
2.4 KiB
C
96 lines
2.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Like the headers that use TRACE_EVENT(), the TRACE_CUSTOM_EVENT()
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* needs a header that allows for multiple inclusions.
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*
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* Test for a unique name (here we have _TRACE_CUSTOM_SCHED_H),
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* also allowing to continue if TRACE_CUSTOM_MULTI_READ is defined.
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*/
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#if !defined(_TRACE_CUSTOM_SCHED_H) || defined(TRACE_CUSTOM_MULTI_READ)
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#define _TRACE_CUSTOM_SCHED_H
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/* Include linux/trace_events.h for initial defines of TRACE_CUSTOM_EVENT() */
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#include <linux/trace_events.h>
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/*
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* TRACE_CUSTOM_EVENT() is just like TRACE_EVENT(). The first parameter
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* is the event name of an existing event where the TRACE_EVENT has been included
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* in the C file before including this file.
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*/
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TRACE_CUSTOM_EVENT(sched_switch,
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/*
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* The TP_PROTO() and TP_ARGS must match the trace event
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* that the custom event is using.
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*/
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TP_PROTO(bool preempt,
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struct task_struct *prev,
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struct task_struct *next,
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unsigned int prev_state),
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TP_ARGS(preempt, prev, next, prev_state),
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/*
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* The next fields are where the customization happens.
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* The TP_STRUCT__entry() defines what will be recorded
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* in the ring buffer when the custom event triggers.
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*
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* The rest is just like the TRACE_EVENT() macro except that
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* it uses the custom entry.
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*/
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TP_STRUCT__entry(
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__field( unsigned short, prev_prio )
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__field( unsigned short, next_prio )
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__field( pid_t, next_pid )
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),
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TP_fast_assign(
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__entry->prev_prio = prev->prio;
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__entry->next_pid = next->pid;
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__entry->next_prio = next->prio;
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),
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TP_printk("prev_prio=%d next_pid=%d next_prio=%d",
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__entry->prev_prio, __entry->next_pid, __entry->next_prio)
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)
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TRACE_CUSTOM_EVENT(sched_waking,
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TP_PROTO(struct task_struct *p),
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TP_ARGS(p),
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TP_STRUCT__entry(
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__field( pid_t, pid )
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__field( unsigned short, prio )
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),
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TP_fast_assign(
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__entry->pid = p->pid;
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__entry->prio = p->prio;
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),
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TP_printk("pid=%d prio=%d", __entry->pid, __entry->prio)
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)
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#endif
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/*
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* Just like the headers that create TRACE_EVENTs, the below must
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* be outside the protection of the above #if block.
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*/
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/*
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* It is required that the Makefile includes:
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* CFLAGS_<c_file>.o := -I$(src)
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*/
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#undef TRACE_INCLUDE_PATH
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#undef TRACE_INCLUDE_FILE
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#define TRACE_INCLUDE_PATH .
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/*
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* It is requred that the TRACE_INCLUDE_FILE be the same
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* as this file without the ".h".
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*/
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#define TRACE_INCLUDE_FILE trace_custom_sched
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#include <trace/define_custom_trace.h>
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