linux/kernel/rcu
Neeraj Upadhyay 65b629e704 rcu-tasks: Inspect stalled task's trc state in locked state
On RCU tasks trace stall, inspect the RCU-tasks-trace specific
states of stalled task in locked down state, using try_invoke_
on_locked_down_task(), to get reliable trc state of a non-running
stalled task.

This was tested using the following command:

tools/testing/selftests/rcutorture/bin/kvm.sh --cpus 8 --configs TRACE01 \
--bootargs "rcutorture.torture_type=tasks-tracing rcutorture.stall_cpu=10 \
rcutorture.stall_cpu_block=1 rcupdate.rcu_task_stall_timeout=100" --trust-make

As expected, this produced the following console output for running and
sleeping tasks.

[   21.520291] INFO: rcu_tasks_trace detected stalls on tasks:
[   21.521292] P85: ... nesting: 1N cpu: 2
[   21.521966] task:rcu_torture_sta state:D stack:15080 pid:   85 ppid:     2
flags:0x00004000
[   21.523384] Call Trace:
[   21.523808]  __schedule+0x273/0x6e0
[   21.524428]  schedule+0x35/0xa0
[   21.524971]  schedule_timeout+0x1ed/0x270
[   21.525690]  ? del_timer_sync+0x30/0x30
[   21.526371]  ? rcu_torture_writer+0x720/0x720
[   21.527106]  rcu_torture_stall+0x24a/0x270
[   21.527816]  kthread+0x115/0x140
[   21.528401]  ? set_kthread_struct+0x40/0x40
[   21.529136]  ret_from_fork+0x22/0x30
[   21.529766]  1 holdouts
[   21.632300] INFO: rcu_tasks_trace detected stalls on tasks:
[   21.632345] rcu_torture_stall end.
[   21.633293] P85: .
[   21.633294] task:rcu_torture_sta state:R  running task stack:15080 pid:
85 ppid:     2 flags:0x00004000
[   21.633299] Call Trace:
[   21.633301]  ? vprintk_emit+0xab/0x180
[   21.633306]  ? vprintk_emit+0x11a/0x180
[   21.633308]  ? _printk+0x4d/0x69
[   21.633311]  ? __default_send_IPI_shortcut+0x1f/0x40

[ paulmck: Update to new v5.16 task_call_func() name. ]

Signed-off-by: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-12-09 10:13:55 -08:00
..
Kconfig rcu_tasks: Convert bespoke callback list to rcu_segcblist structure 2021-12-07 16:26:57 -08:00
Kconfig.debug rcu: Restrict RCU_STRICT_GRACE_PERIOD to at most four CPUs 2021-05-10 16:22:54 -07:00
Makefile rcuperf: Change rcuperf to rcuscale 2020-08-24 18:39:24 -07:00
rcu_segcblist.c rcu/nocb: Remove stale comment above rcu_segcblist_offload() 2021-03-15 13:54:54 -07:00
rcu_segcblist.h rcu/nocb: Code-style nits in callback-offloading toggling 2021-01-06 16:47:55 -08:00
rcu.h Merge branches 'bitmaprange.2021.05.10c', 'doc.2021.05.10c', 'fixes.2021.05.13a', 'kvfree_rcu.2021.05.10c', 'mmdumpobj.2021.05.10c', 'nocb.2021.05.12a', 'srcu.2021.05.12a', 'tasks.2021.05.18a' and 'torture.2021.05.10c' into HEAD 2021-05-18 10:56:19 -07:00
rcuscale.c rcuscale: Warn on individual rcu_scale_init() error conditions 2021-09-13 16:36:16 -07:00
rcutorture.c Merge branches 'fixes.2021.10.07a', 'scftorture.2021.09.16a', 'tasks.2021.09.15a', 'torture.2021.09.13b' and 'torturescript.2021.09.16a' into HEAD 2021-10-07 10:02:17 -07:00
refscale.c refscale: Warn on individual ref_scale_init() error conditions 2021-09-13 16:36:16 -07:00
srcutiny.c srcutiny: Mark read-side data races 2021-08-06 13:41:48 -07:00
srcutree.c Merge branches 'bitmaprange.2021.05.10c', 'doc.2021.05.10c', 'fixes.2021.05.13a', 'kvfree_rcu.2021.05.10c', 'mmdumpobj.2021.05.10c', 'nocb.2021.05.12a', 'srcu.2021.05.12a', 'tasks.2021.05.18a' and 'torture.2021.05.10c' into HEAD 2021-05-18 10:56:19 -07:00
sync.c rcu: Fix various typos in comments 2021-05-12 12:11:05 -07:00
tasks.h rcu-tasks: Inspect stalled task's trc state in locked state 2021-12-09 10:13:55 -08:00
tiny.c srcu: Initialize SRCU after timers 2021-05-10 16:03:35 -07:00
tree_exp.h rcu: Fix existing exp request check in sync_sched_exp_online_cleanup() 2021-09-13 16:32:46 -07:00
tree_nocb.h rcu-nocb: Fix a couple of tree_nocb code-style nits 2021-09-13 16:32:45 -07:00
tree_plugin.h rcu: Always inline rcu_dynticks_task*_{enter,exit}() 2021-10-07 09:59:41 -07:00
tree_stall.h sched,rcu: Rework try_invoke_on_locked_down_task() 2021-10-07 13:51:15 +02:00
tree.c rcu: Fix rcu_dynticks_curr_cpu_in_eqs() vs noinstr 2021-10-07 10:00:07 -07:00
tree.h Merge branches 'bitmaprange.2021.05.10c', 'doc.2021.05.10c', 'fixes.2021.05.13a', 'kvfree_rcu.2021.05.10c', 'mmdumpobj.2021.05.10c', 'nocb.2021.05.12a', 'srcu.2021.05.12a', 'tasks.2021.05.18a' and 'torture.2021.05.10c' into HEAD 2021-05-18 10:56:19 -07:00
update.c RCU pull request for v5.16 2021-11-01 20:25:38 -07:00