From: tip-bot for Thomas Gleixner <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: tglx@linutronix.de, peterz@infradead.org, hpa@zytor.com,
dzickus@redhat.com, npiggin@gmail.com, bp@alien8.de,
cmetcalf@mellanox.com, mingo@kernel.org,
torvalds@linux-foundation.org, uobergfe@redhat.com,
linux-kernel@vger.kernel.org, bigeasy@linutronix.de,
akpm@linux-foundation.org
Subject: [tip:core/urgent] watchdog/core: Rework CPU hotplug locking
Date: Thu, 14 Sep 2017 03:41:57 -0700 [thread overview]
Message-ID: <tip-b7a349819d4b9b5db64e523351e66a79a758eaa5@git.kernel.org> (raw)
In-Reply-To: <20170912194146.568079057@linutronix.de>
Commit-ID: b7a349819d4b9b5db64e523351e66a79a758eaa5
Gitweb: http://git.kernel.org/tip/b7a349819d4b9b5db64e523351e66a79a758eaa5
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Tue, 12 Sep 2017 21:37:00 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 14 Sep 2017 11:41:04 +0200
watchdog/core: Rework CPU hotplug locking
The watchdog proc interface causes extensive recursive locking of the CPU
hotplug percpu rwsem, which is deadlock prone.
Replace the get/put_online_cpus() pairs with cpu_hotplug_disable()/enable()
calls for now. Later patches will remove that requirement completely.
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Link: http://lkml.kernel.org/r/20170912194146.568079057@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/watchdog.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index b2d4675..cd79f64 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -703,7 +703,7 @@ static int proc_watchdog_common(int which, struct ctl_table *table, int write,
int err, old, new;
int *watchdog_param = (int *)table->data;
- get_online_cpus();
+ cpu_hotplug_disable();
mutex_lock(&watchdog_proc_mutex);
/*
@@ -752,7 +752,7 @@ static int proc_watchdog_common(int which, struct ctl_table *table, int write,
}
out:
mutex_unlock(&watchdog_proc_mutex);
- put_online_cpus();
+ cpu_hotplug_enable();
return err;
}
@@ -794,7 +794,7 @@ int proc_watchdog_thresh(struct ctl_table *table, int write,
{
int err, old, new;
- get_online_cpus();
+ cpu_hotplug_disable();
mutex_lock(&watchdog_proc_mutex);
old = ACCESS_ONCE(watchdog_thresh);
@@ -818,7 +818,7 @@ int proc_watchdog_thresh(struct ctl_table *table, int write,
}
out:
mutex_unlock(&watchdog_proc_mutex);
- put_online_cpus();
+ cpu_hotplug_enable();
return err;
}
@@ -833,7 +833,7 @@ int proc_watchdog_cpumask(struct ctl_table *table, int write,
{
int err;
- get_online_cpus();
+ cpu_hotplug_disable();
mutex_lock(&watchdog_proc_mutex);
err = proc_do_large_bitmap(table, write, buffer, lenp, ppos);
@@ -856,7 +856,7 @@ int proc_watchdog_cpumask(struct ctl_table *table, int write,
}
mutex_unlock(&watchdog_proc_mutex);
- put_online_cpus();
+ cpu_hotplug_enable();
return err;
}
next prev parent reply other threads:[~2017-09-14 10:47 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-12 19:36 [patch V2 00/29] lockup_detector: Cure hotplug deadlocks and replace duct tape Thomas Gleixner
2017-09-12 19:36 ` [patch V2 01/29] hardlockup_detector: Provide interface to stop/restart perf events Thomas Gleixner
2017-09-14 10:40 ` [tip:core/urgent] watchdog/hardlockup: " tip-bot for Peter Zijlstra
2017-09-12 19:36 ` [patch V2 02/29] perf/x86/intel: Sanitize PMU HT bug workaround Thomas Gleixner
2017-09-14 10:40 ` [tip:core/urgent] perf/x86/intel, watchdog/core: " tip-bot for Peter Zijlstra
2017-09-12 19:36 ` [patch V2 03/29] lockup_detector: Provide interface to stop from poweroff() Thomas Gleixner
2017-09-14 10:40 ` [tip:core/urgent] watchdog/core: " tip-bot for Thomas Gleixner
2017-09-12 19:36 ` [patch V2 04/29] parisc: Use lockup_detector_stop() Thomas Gleixner
2017-09-14 8:59 ` Helge Deller
2017-09-14 13:46 ` Don Zickus
2017-09-14 10:41 ` [tip:core/urgent] parisc, watchdog/core: " tip-bot for Thomas Gleixner
2017-09-12 19:36 ` [patch V2 05/29] lockup_detector: Remove broken suspend/resume interfaces Thomas Gleixner
2017-09-14 10:41 ` [tip:core/urgent] watchdog/core: " tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 06/29] lockup_detector: Rework cpu hotplug locking Thomas Gleixner
2017-09-14 10:41 ` tip-bot for Thomas Gleixner [this message]
2017-09-12 19:37 ` [patch V2 07/29] lockup_detector: Rename watchdog_proc_mutex Thomas Gleixner
2017-09-14 10:42 ` [tip:core/urgent] watchdog/core: " tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 08/29] lockup_detector: Mark hardlockup_detector_disable() __init Thomas Gleixner
2017-09-14 10:42 ` [tip:core/urgent] watchdog/core: " tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 09/29] lockup_detector/perf: Remove broken self disable on failure Thomas Gleixner
2017-09-14 10:43 ` [tip:core/urgent] watchdog/hardlockup/perf: " tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 10/29] lockup_detector/perf: Prevent cpu hotplug deadlock Thomas Gleixner
2017-09-14 10:43 ` [tip:core/urgent] watchdog/hardlockup/perf: Prevent CPU " tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 11/29] lockup_detector: Remove park_in_progress obfuscation Thomas Gleixner
2017-09-12 19:37 ` [patch V2 12/29] lockup_detector: Cleanup stub functions Thomas Gleixner
2017-09-14 10:44 ` [tip:core/urgent] watchdog/core: Clean up " tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 13/29] lockup_detector: Cleanup the ifdef maze Thomas Gleixner
2017-09-14 10:44 ` [tip:core/urgent] watchdog/core: Clean up the #ifdef maze tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 14/29] lockup_detector: Split out cpumask write function Thomas Gleixner
2017-09-14 10:45 ` [tip:core/urgent] watchdog/core: " tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 15/29] smpboot/threads: Avoid runtime allocation Thomas Gleixner
2017-09-14 10:45 ` [tip:core/urgent] smpboot/threads, watchdog/core: " tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 16/29] lockup_detector: Create new thread handling infrastructure Thomas Gleixner
2017-09-14 10:45 ` [tip:core/urgent] watchdog/core: " tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 17/29] lockup_detector: Get rid of the thread teardown/setup dance Thomas Gleixner
2017-09-14 10:46 ` [tip:core/urgent] watchdog/core: " tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 18/29] lockup_detector: Further simplify sysctl handling Thomas Gleixner
2017-09-14 10:46 ` [tip:core/urgent] watchdog/core: " tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 19/29] lockup_detector: Cleanup header mess Thomas Gleixner
2017-09-14 10:47 ` [tip:core/urgent] watchdog/core: Clean up " tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 20/29] lockup_detector/sysctl: Get rid of the ifdeffery Thomas Gleixner
2017-09-14 10:47 ` [tip:core/urgent] watchdog/sysctl: Get rid of the #ifdeffery tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 21/29] lockup_detector: Cleanup sysctl variable name space Thomas Gleixner
2017-09-14 10:47 ` [tip:core/urgent] watchdog/sysctl: Clean up " tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 22/29] lockup_detector: Make watchdog_nmi_reconfigure() two stage Thomas Gleixner
2017-09-14 10:48 ` [tip:core/urgent] watchdog/core, powerpc: " tip-bot for Thomas Gleixner
2017-10-03 0:29 ` [patch V2 22/29] lockup_detector: " Michael Ellerman
2017-10-03 6:50 ` Thomas Gleixner
2017-10-03 7:04 ` Thomas Gleixner
2017-10-03 10:01 ` Nicholas Piggin
2017-10-03 10:56 ` Thomas Gleixner
2017-10-03 11:36 ` Michael Ellerman
2017-10-03 12:13 ` Thomas Gleixner
2017-10-03 13:20 ` Thomas Gleixner
2017-10-03 19:27 ` Thomas Gleixner
2017-10-04 5:53 ` Michael Ellerman
2017-10-05 16:17 ` Don Zickus
2017-09-12 19:37 ` [patch V2 23/29] lockup_detector: Get rid of the racy update loop Thomas Gleixner
2017-09-14 10:48 ` [tip:core/urgent] watchdog/core: " tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 24/29] lockup_detector/perf: Implement init time perf validation Thomas Gleixner
2017-09-14 10:48 ` [tip:core/urgent] watchdog/hardlockup/perf: " tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 25/29] lockup_detector: Implement init time detection of perf Thomas Gleixner
2017-09-13 18:02 ` Don Zickus
2017-09-13 18:05 ` Thomas Gleixner
2017-09-14 5:27 ` Ingo Molnar
2017-09-14 10:49 ` [tip:core/urgent] watchdog/hardlockup/perf: " tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 26/29] lockup_detector/perf: Implement CPU enable replacement Thomas Gleixner
2017-09-14 10:49 ` [tip:core/urgent] watchdog/hardlockup/perf: " tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 27/29] lockup_detector: Use new perf CPU enable mechanism Thomas Gleixner
2017-09-14 10:50 ` [tip:core/urgent] watchdog/hardlockup/perf: " tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 28/29] lockup_detector/perf: Simplify deferred event destroy Thomas Gleixner
2017-09-14 10:50 ` [tip:core/urgent] watchdog/hardlockup/perf: " tip-bot for Thomas Gleixner
2017-09-12 19:37 ` [patch V2 29/29] lockup_detector: Cleanup hotplug locking mess Thomas Gleixner
2017-09-14 10:50 ` [tip:core/urgent] watchdog/hardlockup: Clean up " tip-bot for Thomas Gleixner
2017-09-13 18:06 ` [patch V2 00/29] lockup_detector: Cure hotplug deadlocks and replace duct tape Don Zickus
2017-09-14 5:27 ` Ingo Molnar
2017-09-14 8:11 ` Thomas Gleixner
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