From 9c2136be0878c88c53dea26943ce40bb03ad8d8d Mon Sep 17 00:00:00 2001 From: Delyan Kratunov Date: Wed, 11 May 2022 18:28:36 +0000 Subject: [PATCH] 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 Signed-off-by: Peter Zijlstra (Intel) Acked-by: Steven Rostedt (Google) Link: https://lkml.kernel.org/r/c8a6930dfdd58a4a5755fc01732675472979732b.camel@fb.com --- include/trace/events/sched.h | 6 +++--- kernel/sched/core.c | 2 +- kernel/trace/fgraph.c | 4 ++-- kernel/trace/ftrace.c | 4 ++-- kernel/trace/trace_events.c | 8 ++++---- kernel/trace/trace_osnoise.c | 4 ++-- kernel/trace/trace_sched_switch.c | 4 ++-- kernel/trace/trace_sched_wakeup.c | 4 ++-- samples/trace_events/trace_custom_sched.h | 6 +++--- 9 files changed, 21 insertions(+), 21 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 ) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 51efaabac3e4..d58c0389eb23 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6382,7 +6382,7 @@ static void __sched notrace __schedule(unsigned int sched_mode) migrate_disable_switch(rq, prev); psi_sched_switch(prev, next, !task_on_rq_queued(prev)); - trace_sched_switch(sched_mode & SM_MASK_PREEMPT, prev_state, prev, next); + trace_sched_switch(sched_mode & SM_MASK_PREEMPT, prev, next, prev_state); /* Also unlocks the rq: */ rq = context_switch(rq, prev, next, &rf); diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c index 8f4fb328133a..a7e84c8543cb 100644 --- a/kernel/trace/fgraph.c +++ b/kernel/trace/fgraph.c @@ -404,9 +404,9 @@ free: static void ftrace_graph_probe_sched_switch(void *ignore, bool preempt, - unsigned int prev_state, struct task_struct *prev, - struct task_struct *next) + struct task_struct *next, + unsigned int prev_state) { unsigned long long timestamp; int index; diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 4f1d2f5e7263..af899b058c8d 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -7420,9 +7420,9 @@ ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops) static void ftrace_filter_pid_sched_switch_probe(void *data, bool preempt, - unsigned int prev_state, struct task_struct *prev, - struct task_struct *next) + struct task_struct *next, + unsigned int prev_state) { struct trace_array *tr = data; struct trace_pid_list *pid_list; diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index e11e167b7809..f97de82d1342 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -773,9 +773,9 @@ void trace_event_follow_fork(struct trace_array *tr, bool enable) static void event_filter_pid_sched_switch_probe_pre(void *data, bool preempt, - unsigned int prev_state, struct task_struct *prev, - struct task_struct *next) + struct task_struct *next, + unsigned int prev_state) { struct trace_array *tr = data; struct trace_pid_list *no_pid_list; @@ -799,9 +799,9 @@ event_filter_pid_sched_switch_probe_pre(void *data, bool preempt, static void event_filter_pid_sched_switch_probe_post(void *data, bool preempt, - unsigned int prev_state, struct task_struct *prev, - struct task_struct *next) + struct task_struct *next, + unsigned int prev_state) { struct trace_array *tr = data; struct trace_pid_list *no_pid_list; diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c index e9ae1f33a7f0..afb92e2f0aea 100644 --- a/kernel/trace/trace_osnoise.c +++ b/kernel/trace/trace_osnoise.c @@ -1168,9 +1168,9 @@ thread_exit(struct osnoise_variables *osn_var, struct task_struct *t) */ static void trace_sched_switch_callback(void *data, bool preempt, - unsigned int prev_state, struct task_struct *p, - struct task_struct *n) + struct task_struct *n, + unsigned int prev_state) { struct osnoise_variables *osn_var = this_cpu_osn_var(); diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index 45796d8bd4b2..c9ffdcfe622e 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -22,8 +22,8 @@ static DEFINE_MUTEX(sched_register_mutex); static void probe_sched_switch(void *ignore, bool preempt, - unsigned int prev_state, - struct task_struct *prev, struct task_struct *next) + struct task_struct *prev, struct task_struct *next, + unsigned int prev_state) { int flags; diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c index 46429f9a96fa..330aee1c1a49 100644 --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -426,8 +426,8 @@ tracing_sched_wakeup_trace(struct trace_array *tr, static void notrace probe_wakeup_sched_switch(void *ignore, bool preempt, - unsigned int prev_state, - struct task_struct *prev, struct task_struct *next) + struct task_struct *prev, struct task_struct *next, + unsigned int prev_state) { struct trace_array_cpu *data; u64 T0, T1, delta; diff --git a/samples/trace_events/trace_custom_sched.h b/samples/trace_events/trace_custom_sched.h index 9fdd8e7c2a45..951388334a3f 100644 --- a/samples/trace_events/trace_custom_sched.h +++ b/samples/trace_events/trace_custom_sched.h @@ -25,11 +25,11 @@ TRACE_CUSTOM_EVENT(sched_switch, * that the custom event is using. */ 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), /* * The next fields are where the customization happens.