From: Frederic Weisbecker <frederic@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>,
"Paul E . McKenney" <paulmck@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Frederic Weisbecker <frederic@kernel.org>,
"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
stable@vger.kernel.org
Subject: [RFC PATCH 7/8] entry: Report local wake up on resched blind zone while resuming to user
Date: Sat, 9 Jan 2021 03:05:35 +0100 [thread overview]
Message-ID: <20210109020536.127953-8-frederic@kernel.org> (raw)
In-Reply-To: <20210109020536.127953-1-frederic@kernel.org>
The last rescheduling opportunity while resuming to user is in
exit_to_user_mode_loop(). This means that any wake up performed on
the local runqueue after this point is going to have its rescheduling
silently ignored.
Perform sanity checks to report these situations.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar<mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
kernel/entry/common.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index 8f3292b5f9b7..1dfb97762336 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -5,6 +5,7 @@
#include <linux/highmem.h>
#include <linux/livepatch.h>
#include <linux/audit.h>
+#include <linux/sched.h>
#include "common.h"
@@ -23,6 +24,8 @@ static __always_inline void __enter_from_user_mode(struct pt_regs *regs)
instrumentation_begin();
trace_hardirqs_off_finish();
instrumentation_end();
+
+ sched_resched_local_allow();
}
void noinstr enter_from_user_mode(struct pt_regs *regs)
@@ -206,6 +209,7 @@ static void exit_to_user_mode_prepare(struct pt_regs *regs)
if (unlikely(ti_work & EXIT_TO_USER_MODE_WORK))
ti_work = exit_to_user_mode_loop(regs, ti_work);
+ sched_resched_local_forbid();
arch_exit_to_user_mode_prepare(regs, ti_work);
/* Ensure that the address limit is intact and no locks are held */
--
2.25.1
next prev parent reply other threads:[~2021-01-09 2:07 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-09 2:05 [RFC PATCH 0/8] rcu/sched: Fix ignored rescheduling after rcu_eqs_enter() v3 Frederic Weisbecker
2021-01-09 2:05 ` [RFC PATCH 1/8] rcu: Remove superfluous rdp fetch Frederic Weisbecker
2021-01-09 9:03 ` Greg KH
2021-01-10 10:59 ` Frederic Weisbecker
2021-01-09 2:05 ` [RFC PATCH 2/8] rcu: Pull deferred rcuog wake up to rcu_eqs_enter() callers Frederic Weisbecker
2021-01-09 2:05 ` [RFC PATCH 3/8] rcu/nocb: Perform deferred wake up before last idle's need_resched() check Frederic Weisbecker
2021-01-09 2:05 ` [RFC PATCH 4/8] rcu/nocb: Trigger self-IPI on late deferred wake up before user resume Frederic Weisbecker
2021-01-11 12:04 ` Peter Zijlstra
2021-01-11 12:35 ` Frederic Weisbecker
2021-01-09 2:05 ` [RFC PATCH 5/8] entry: Explicitly flush pending rcuog wakeup before last rescheduling points Frederic Weisbecker
2021-01-11 0:40 ` Frederic Weisbecker
2021-01-11 5:13 ` Paul E. McKenney
2021-01-11 11:50 ` Frederic Weisbecker
2021-01-11 12:08 ` Peter Zijlstra
2021-01-11 12:54 ` Frederic Weisbecker
2021-01-09 2:05 ` [RFC PATCH 6/8] sched: Report local wake up on resched blind zone within idle loop Frederic Weisbecker
2021-01-11 12:25 ` Peter Zijlstra
2021-01-11 12:56 ` Frederic Weisbecker
2021-01-12 8:24 ` [sched] 9720a64438: WARNING:at_kernel/sched/core.c:#sched_resched_local_assert_allowed kernel test robot
[not found] ` <161062476680.19482.8402362019173198799@build.alporthouse.com>
2021-01-14 15:19 ` [RFC PATCH 6/8] sched: Report local wake up on resched blind zone within idle loop Paul E. McKenney
2021-01-09 2:05 ` Frederic Weisbecker [this message]
2021-01-13 2:46 ` [entry] 8e01c5f104: unixbench.score -2.2% regression kernel test robot
2021-01-09 2:05 ` [RFC PATCH 8/8] timer: Report ignored local enqueue in nohz mode Frederic Weisbecker
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210109020536.127953-8-frederic@kernel.org \
--to=frederic@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=paulmck@kernel.org \
--cc=peterz@infradead.org \
--cc=rafael.j.wysocki@intel.com \
--cc=stable@vger.kernel.org \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).