Hi Byungchul,
Thanks for your great work for the latest dept patch.
But I have a some quetions with the below dept log supplied from
Yunseong Kim<yskelg@xxxxxxxxx>
...
[13304.604203] context A
[13304.604209] [S] lock(&uprobe->register_rwsem:0)
[13304.604217] [W] __wait_rcu_gp(<sched>:0)
[13304.604226] [E] unlock(&uprobe->register_rwsem:0)
[13304.604234]
[13304.604239] context B
[13304.604244] [S] lock(event_mutex:0)
[13304.604252] [W] lock(&uprobe->register_rwsem:0)
[13304.604261] [E] unlock(event_mutex:0)
[13304.604269]
[13304.604274] context C
[13304.604279] [S] lock(&ctx->mutex:0)
[13304.604287] [W] lock(event_mutex:0)
[13304.604295] [E] unlock(&ctx->mutex:0)
[13304.604303]
[13304.604308] context D
[13304.604313] [S] lock(&sig->exec_update_lock:0)
[13304.604322] [W] lock(&ctx->mutex:0)
[13304.604330] [E] unlock(&sig->exec_update_lock:0)
[13304.604338]
[13304.604343] context E
[13304.604348] [S] lock(&f->f_pos_lock:0)
[13304.604356] [W] lock(&sig->exec_update_lock:0)
[13304.604365] [E] unlock(&f->f_pos_lock:0)
[13304.604373]
[13304.604378] context F
[13304.604383] [S] (unknown)(<sched>:0)
[13304.604391] [W] lock(&f->f_pos_lock:0)
[13304.604399] [E] try_to_wake_up(<sched>:0)
[13304.604408]
[13304.604413] context G
[13304.604418] [S] lock(btrfs_trans_num_writers:0)
[13304.604427] [W] btrfs_commit_transaction(<sched>:0)
[13304.604436] [E] unlock(btrfs_trans_num_writers:0)
[13304.604445]
[13304.604449] context H
[13304.604455] [S] (unknown)(<sched>:0)
[13304.604463] [W] lock(btrfs_trans_num_writers:0)
[13304.604471] [E] try_to_wake_up(<sched>:0)
[13304.604484] context I
[13304.604490] [S] (unknown)(<sched>:0)
[13304.604498] [W] synchronize_rcu_expedited_wait_once(<sched>:0)
[13304.604507] --------------- >8 timeout ---------------
[13304.604527] context J
[13304.604533] [S] (unknown)(<sched>:0)
[13304.604541] [W] synchronize_rcu_expedited(<sched>:0)
[13304.604549] [E] try_to_wake_up(<sched>:0)
[end of circular]
...
1. I wonder how context A could be printed with
[13304.604217] [W] __wait_rcu_gp(<sched>:0)
since, the completion's dept map will be initailized with
sdt_might_sleep_start_timeout((x)->dmap, -1L);
I think last dept_task's stage_sched_map affects this wrong print.
Should this be fixed with:
@@ -2713,6 +2713,7 @@ void dept_stage_wait(struct dept_map *m, struct dept_key *k,
if (m) {
dt->stage_m = *m;
dt->stage_real_m = m;
+ dt->stage_sched_map = false;
/*
* Ensure dt->stage_m.keys != NULL and it works with the
2. Whenever prints the dependency which initalized with sdt_might_sleep_start_timeout() currently it prints
(unknown)(<sched>:0) only.
Would it much better to print task information? (pid, comm and other).
Thanks.