linux-kernel - [tip:sched/core] sched, tracing: Fix trace_sched_pi

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <tip-4ff648decf4712d39f184fc2df3163f43975575a@git.kernel.org>
Date:   Fri, 25 May 2018 02:47:20 -0700
From:   tip-bot for Sebastian Andrzej Siewior <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     peterz@...radead.org, tglx@...utronix.de, hpa@...or.com,
        bigeasy@...utronix.de, man@...a.com, linux-kernel@...r.kernel.org,
        rostedt@...dmis.org, torvalds@...ux-foundation.org,
        mingo@...nel.org
Subject: [tip:sched/core] sched, tracing: Fix trace_sched_pi_setprio() for
 deboosting

Commit-ID:  4ff648decf4712d39f184fc2df3163f43975575a
Gitweb:     https://git.kernel.org/tip/4ff648decf4712d39f184fc2df3163f43975575a
Author:     Sebastian Andrzej Siewior <bigeasy@...utronix.de>
AuthorDate: Thu, 24 May 2018 15:26:48 +0200
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Fri, 25 May 2018 08:04:01 +0200

sched, tracing: Fix trace_sched_pi_setprio() for deboosting

Since the following commit:

  b91473ff6e97 ("sched,tracing: Update trace_sched_pi_setprio()")

the sched_pi_setprio trace point shows the "newprio" during a deboost:

  |futex sched_pi_setprio: comm=futex_requeue_p pid"34 oldprio newprio=3D98
  |futex sched_switch: prev_comm=futex_requeue_p prev_pid"34 prev_prio=120

This patch open codes __rt_effective_prio() in the tracepoint as the
'newprio' to get the old behaviour back / the correct priority:

  |futex sched_pi_setprio: comm=futex_requeue_p pid"20 oldprio newprio=3D120
  |futex sched_switch: prev_comm=futex_requeue_p prev_pid"20 prev_prio=120

Peter suggested to open code the new priority so people using tracehook
could get the deadline data out.

Reported-by: Mansky Christian <man@...a.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Steven Rostedt <rostedt@...dmis.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Fixes: b91473ff6e97 ("sched,tracing: Update trace_sched_pi_setprio()")
Link: http://lkml.kernel.org/r/20180524132647.gg6ziuogczdmjjzu@linutronix.de
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 include/trace/events/sched.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index bc01e06bc716..0be866c91f62 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -435,7 +435,9 @@ TRACE_EVENT(sched_pi_setprio,
 		memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN);
 		__entry->pid		= tsk->pid;
 		__entry->oldprio	= tsk->prio;
-		__entry->newprio	= pi_task ? pi_task->prio : tsk->prio;
+		__entry->newprio	= pi_task ?
+				min(tsk->normal_prio, pi_task->prio) :
+				tsk->normal_prio;
 		/* XXX SCHED_DEADLINE bits missing */
 	),