linux-kernelorg-stable/kernel/trace
Valentin Schneider fa2c3254d7 sched/tracing: Don't re-read p->state when emitting sched_switch event
As of commit

  c6e7bd7afa ("sched/core: Optimize ttwu() spinning on p->on_cpu")

the following sequence becomes possible:

		      p->__state = TASK_INTERRUPTIBLE;
		      __schedule()
			deactivate_task(p);
  ttwu()
    READ !p->on_rq
    p->__state=TASK_WAKING
			trace_sched_switch()
			  __trace_sched_switch_state()
			    task_state_index()
			      return 0;

TASK_WAKING isn't in TASK_REPORT, so the task appears as TASK_RUNNING in
the trace event.

Prevent this by pushing the value read from __schedule() down the trace
event.

Reported-by: Abhijeet Dharmapurikar <adharmap@quicinc.com>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20220120162520.570782-2-valentin.schneider@arm.com
2022-03-01 16:18:39 +01:00
..
Kconfig ftrace: Have architectures opt-in for mcount build time sorting 2022-01-27 19:15:44 -05:00
Makefile tracing: Place trace_pid_list logic into abstract functions 2021-10-05 17:30:08 -04:00
blktrace.c blktrace: switch trace spinlock to a raw spinlock 2021-12-20 13:50:14 -07:00
bpf_trace.c bpf: Add MEM_RDONLY for helper args that are pointers to rdonly mem. 2021-12-18 13:27:41 -08:00
bpf_trace.h
error_report-traces.c
fgraph.c sched/tracing: Don't re-read p->state when emitting sched_switch event 2022-03-01 16:18:39 +01:00
ftrace.c sched/tracing: Don't re-read p->state when emitting sched_switch event 2022-03-01 16:18:39 +01:00
ftrace_internal.h
kprobe_event_gen_test.c
pid_list.c tracing: Initialize upper and lower vars in pid_list_refill_irq() 2021-10-07 09:56:38 -04:00
pid_list.h tracing: Create a sparse bitmask for pid filtering 2021-10-05 17:38:45 -04:00
power-traces.c
preemptirq_delay_test.c
ring_buffer.c ring-buffer: make use of the helper function kthread_run_on_cpu() 2022-01-15 16:30:23 +02:00
ring_buffer_benchmark.c
rpm-traces.c
synth_event_gen_test.c
trace.c tracing: Fix tp_printk option related with tp_printk_stop_on_boot 2022-02-08 15:47:00 -05:00
trace.h tracing: Add helper functions to simplify event_command.parse() callback handling 2022-01-10 11:09:11 -05:00
trace_benchmark.c
trace_benchmark.h
trace_boot.c tracing: Fix missing trace_boot_init_histograms kstrdup NULL checks 2021-10-26 09:18:10 -04:00
trace_branch.c
trace_clock.c
trace_dynevent.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
trace_dynevent.h tracing: Add DYNAMIC flag for dynamic events 2021-08-18 18:10:32 -04:00
trace_entries.h
trace_eprobe.c tracing: Remove ops param from event_command reg()/unreg() callbacks 2022-01-10 11:09:11 -05:00
trace_event_perf.c tracing: Show size of requested perf buffer 2021-10-27 12:25:09 -04:00
trace_events.c sched/tracing: Don't re-read p->state when emitting sched_switch event 2022-03-01 16:18:39 +01:00
trace_events_filter.c tracing: Add ustring operation to filtering string pointers 2022-01-14 03:42:24 -05:00
trace_events_filter_test.h
trace_events_hist.c tracing: Propagate is_signed to expression 2022-01-27 19:15:49 -05:00
trace_events_inject.c tracing: Support __rel_loc relative dynamic data location attribute 2021-12-06 15:37:21 -05:00
trace_events_synth.c Tracing updates for 5.17: 2022-01-16 10:15:32 +02:00
trace_events_trigger.c tracing: Add helper functions to simplify event_command.parse() callback handling 2022-01-10 11:09:11 -05:00
trace_export.c
trace_functions.c ftrace: disable preemption when recursion locked 2021-10-27 11:21:49 -04:00
trace_functions_graph.c tracing: in_irq() cleanup 2021-10-13 18:19:41 -04:00
trace_hwlat.c trace/hwlat: make use of the helper function kthread_run_on_cpu() 2022-01-15 16:30:24 +02:00
trace_irqsoff.c
trace_kdb.c
trace_kprobe.c Tracing updates for 5.17: 2022-01-16 10:15:32 +02:00
trace_kprobe_selftest.c
trace_kprobe_selftest.h
trace_mmiotrace.c
trace_nop.c
trace_osnoise.c sched/tracing: Don't re-read p->state when emitting sched_switch event 2022-03-01 16:18:39 +01:00
trace_output.c tracing: Account bottom half disabled sections. 2022-01-13 16:23:04 -05:00
trace_output.h
trace_preemptirq.c
trace_printk.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
trace_probe.c tracing/probes: check the return value of kstrndup() for pbuf 2022-01-13 16:23:04 -05:00
trace_probe.h tracing: Add a probe that attaches to trace events 2021-08-20 14:18:40 -04:00
trace_probe_tmpl.h tracing/probes: Have process_fetch_insn() take a void * instead of pt_regs 2021-08-19 09:09:03 -04:00
trace_recursion_record.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
trace_sched_switch.c sched/tracing: Don't re-read p->state when emitting sched_switch event 2022-03-01 16:18:39 +01:00
trace_sched_wakeup.c sched/tracing: Don't re-read p->state when emitting sched_switch event 2022-03-01 16:18:39 +01:00
trace_selftest.c tracing: Fix selftest config check for function graph start up test 2021-10-21 14:18:48 -04:00
trace_selftest_dynamic.c
trace_seq.c
trace_stack.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
trace_stat.c tracing: Disable "other" permission bits in the tracefs files 2021-10-08 18:08:43 -04:00
trace_stat.h
trace_synth.h tracing: synth events: increase max fields count 2021-09-08 15:29:16 -04:00
trace_syscalls.c tracing: Have syscall trace events use trace_event_buffer_lock_reserve() 2022-01-13 16:23:05 -05:00
trace_uprobe.c Tracing updates for 5.17: 2022-01-16 10:15:32 +02:00
tracing_map.c tracing: Fix a kmemleak false positive in tracing_map 2021-12-01 21:04:34 -05:00
tracing_map.h