The rtapp/sleep monitor detects real-time tasks which go to sleep in an
real-time-unsafe manner. If this happen, the monitor triggers a trace event
in the sched_wakeup tracepoint's handler.
However, the invoking context of that trace event is not the most
informative, because of the stack trace of that event is the wakeup's code
path which is not very helpful:
74.669317: rv:error_sleep: condvar[254]: violation detected
ltl_validate+0x345 ([kernel.kallsyms])
handle_sched_wakeup+0x34 ([kernel.kallsyms])
ttwu_do_activate+0xff ([kernel.kallsyms])
sched_ttwu_pending+0x104 ([kernel.kallsyms])
__flush_smp_call_function_queue+0x15b ([kernel.kallsyms])
__sysvec_call_function_single+0x18 ([kernel.kallsyms])
sysvec_call_function_single+0x66 ([kernel.kallsyms])
asm_sysvec_call_function_single+0x1a ([kernel.kallsyms])
pv_native_safe_halt+0xf ([kernel.kallsyms])
default_idle+0x9 ([kernel.kallsyms])
default_idle_call+0x33 ([kernel.kallsyms])
do_idle+0x234 ([kernel.kallsyms])
cpu_startup_entry+0x24 ([kernel.kallsyms])
start_secondary+0xf8 ([kernel.kallsyms])
common_startup_64+0x13e ([kernel.kallsyms])
What would be much more valuable is the stack trace of the task itself.
Change the update of WAKEUP from being in sched_wakeup trace point's
handler to sched_exit trace point's handler. This makes the event happen in
the task's context, making the stack trace far more informative for user:
rv:error_sleep: condvar[254]: violation detected
ltl_validate+0x345 ([kernel.kallsyms])
handle_sched_exit+0x39 ([kernel.kallsyms])
__schedule+0x80f ([kernel.kallsyms])
schedule+0x22 ([kernel.kallsyms])
futex_do_wait+0x33 ([kernel.kallsyms])
__futex_wait+0x8c ([kernel.kallsyms])
futex_wait+0x73 ([kernel.kallsyms])
do_futex+0xc6 ([kernel.kallsyms])
__x64_sys_futex+0x121 ([kernel.kallsyms])
do_syscall_64+0xf3 ([kernel.kallsyms])
entry_SYSCALL_64_after_hwframe+0x77 ([kernel.kallsyms])
__futex_abstimed_wait_common64+0xc6 (inlined)
__futex_abstimed_wait_common+0xc6 (/usr/lib/x86_64-linux-gnu/libc.so.6)
Signed-off-by: Nam Cao <[email protected]>
---
kernel/trace/rv/monitors/sleep/sleep.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/kernel/trace/rv/monitors/sleep/sleep.c
b/kernel/trace/rv/monitors/sleep/sleep.c
index 8dfe5ec13e19..0a36f5519e6b 100644
--- a/kernel/trace/rv/monitors/sleep/sleep.c
+++ b/kernel/trace/rv/monitors/sleep/sleep.c
@@ -92,9 +92,9 @@ static void handle_sched_set_state(void *data, struct
task_struct *task, int sta
ltl_atom_pulse(task, LTL_ABORT_SLEEP, true);
}
-static void handle_sched_wakeup(void *data, struct task_struct *task)
+static void handle_sched_exit(void *data, bool is_switch)
{
- ltl_atom_pulse(task, LTL_WAKE, true);
+ ltl_atom_pulse(current, LTL_WAKE, true);
}
static void handle_sched_waking(void *data, struct task_struct *task)
@@ -200,7 +200,7 @@ static int enable_sleep(void)
return retval;
rv_attach_trace_probe("rtapp_sleep", sched_waking, handle_sched_waking);
- rv_attach_trace_probe("rtapp_sleep", sched_wakeup, handle_sched_wakeup);
+ rv_attach_trace_probe("rtapp_sleep", sched_exit_tp, handle_sched_exit);
rv_attach_trace_probe("rtapp_sleep", sched_set_state_tp,
handle_sched_set_state);
rv_attach_trace_probe("rtapp_sleep", contention_begin,
handle_contention_begin);
rv_attach_trace_probe("rtapp_sleep", contention_end,
handle_contention_end);
@@ -213,7 +213,7 @@ static int enable_sleep(void)
static void disable_sleep(void)
{
rv_detach_trace_probe("rtapp_sleep", sched_waking, handle_sched_waking);
- rv_detach_trace_probe("rtapp_sleep", sched_wakeup, handle_sched_wakeup);
+ rv_detach_trace_probe("rtapp_sleep", sched_exit_tp, handle_sched_exit);
rv_detach_trace_probe("rtapp_sleep", sched_set_state_tp,
handle_sched_set_state);
rv_detach_trace_probe("rtapp_sleep", contention_begin,
handle_contention_begin);
rv_detach_trace_probe("rtapp_sleep", contention_end,
handle_contention_end);
--
2.47.3
