The kernel document 'tracing: trace event triggers' said i can use stacktrace cmd to dump a stacktrace to the trace buffer whenever the trigger event is hit. But all i got is a simple string "stacktrace". Here is my configure:
cd /sys/kernel/debug/tracing/events/sched/sched_switch
echo 1 > enable
echo 'stacktrace' > trigger
cat trigger
stacktrace:unlimited
When i Looking at the 'trace' output, here is what i saw:
kworker/u2:0-4002 [000] d... 1275475.478000: sched_switch: prev_comm=kworker/u2:0 prev_pid=4002 prev_prio=120 prev_state=S ==> next_comm=sshd next_pid=3048 next_prio=120
kworker/u2:0-4002 [000] d... 1275475.478000: <stack trace>
sshd-3048 [000] d... 1275475.478000: sched_switch: prev_comm=sshd prev_pid=3048 prev_prio=120 prev_state=S ==> next_comm=vim next_pid=4059 next_prio=120
sshd-3048 [000] d... 1275475.478000: <stack trace>
vim-4059 [000] d... 1275475.479000: sched_switch: prev_comm=vim prev_pid=4059 prev_prio=120 prev_state=R ==> next_comm=rcu_sched next_pid=8 next_prio=120
vim-4059 [000] d... 1275475.479000: <stack trace>
rcu_sched-8 [000] d... 1275475.479000: sched_switch: prev_comm=rcu_sched prev_pid=8 prev_prio=120 prev_state=S ==> next_comm=vim next_pid=4059 next_prio=120
rcu_sched-8 [000] d... 1275475.479000: <stack trace>
vim-4059 [000] d... 1275475.481000: sched_switch: prev_comm=vim prev_pid=4059 prev_prio=120 prev_state=R ==> next_comm=rcu_sched next_pid=8 next_prio=120
vim-4059 [000] d... 1275475.481000: <stack trace>
rcu_sched-8 [000] d... 1275475.481000: sched_switch: prev_comm=rcu_sched prev_pid=8 prev_prio=120 prev_state=S ==> next_comm=vim next_pid=4059 next_prio=120
rcu_sched-8 [000] d... 1275475.481000: <stack trace>
vim-4059 [000] d... 1275475.482000: sched_switch: prev_comm=vim prev_pid=4059 prev_prio=120 prev_state=R ==> next_comm=rcu_sched next_pid=8 next_prio=120
vim-4059 [000] d... 1275475.482000: <stack trace>
rcu_sched-8 [000] d... 1275475.482000: sched_switch: prev_comm=rcu_sched prev_pid=8 prev_prio=120 prev_state=S ==> next_comm=vim next_pid=4059 next_prio=120
rcu_sched-8 [000] d... 1275475.482000: <stack trace>
vim-4059 [000] d... 1275475.483000: sched_switch: prev_comm=vim prev_pid=4059 prev_prio=120 prev_state=R+ ==> next_comm=rcu_sched next_pid=8 next_prio=120
vim-4059 [000] d... 1275475.483000: <stack trace>
rcu_sched-8 [000] d... 1275475.483000: sched_switch: prev_comm=rcu_sched prev_pid=8 prev_prio=120 prev_state=S ==> next_comm=ksoftirqd/0 next_pid=7 next_prio=120
rcu_sched-8 [000] d... 1275475.483000: <stack trace>
ksoftirqd/0-7 [000] d... 1275475.483000: sched_switch: prev_comm=ksoftirqd/0 prev_pid=7 prev_prio=120 prev_state=S ==> next_comm=rcu_sched next_pid=8 next_prio=120
ksoftirqd/0-7 [000] d... 1275475.483000: <stack trace>
rcu_sched-8 [000] d... 1275475.483000: sched_switch: prev_comm=rcu_sched prev_pid=8 prev_prio=120 prev_state=S ==> next_comm=vim next_pid=4059 next_prio=120
rcu_sched-8 [000] d... 1275475.483000: <stack trace>
How do I make it so that stacktrace dump all the stack traces.
