From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
To: paulus@samba.org, oleg@redhat.com, mingo@kernel.org,
rjw@rjwysocki.net, rusty@rustcorp.com.au, peterz@infradead.org,
tglx@linutronix.de, akpm@linux-foundation.org
Cc: linux-arch@vger.kernel.org, ego@linux.vnet.ibm.com,
walken@google.com, linux@arm.linux.org.uk,
linux-pm@vger.kernel.org, Li RongQing <roy.qing.li@gmail.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
Chris Metcalf <cmetcalf@tilera.com>,
"David S. Miller" <davem@davemloft.net>,
linuxppc-dev@ozlabs.org,
"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>,
tj@kernel.org, Sasha Levin <sasha.levin@oracle.com>,
Andrew Morton <akpm@linux-foundation.org>,
paulmck@linux.vnet.ibm.com, Ingo Molnar <mingo@kernel.org>
Subject: [PATCH v3 51/52] net/core/flow.c: Fix CPU hotplug callback registration
Date: Tue, 11 Mar 2014 02:12:51 +0530 [thread overview]
Message-ID: <20140310204250.10746.61946.stgit@srivatsabhat.in.ibm.com> (raw)
In-Reply-To: <20140310203312.10746.310.stgit@srivatsabhat.in.ibm.com>
Subsystems that want to register CPU hotplug callbacks, as well as perform
initialization for the CPUs that are already online, often do it as shown
below:
get_online_cpus();
for_each_online_cpu(cpu)
init_cpu(cpu);
register_cpu_notifier(&foobar_cpu_notifier);
put_online_cpus();
This is wrong, since it is prone to ABBA deadlocks involving the
cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently
with CPU hotplug operations).
Instead, the correct and race-free way of performing the callback
registration is:
cpu_notifier_register_begin();
for_each_online_cpu(cpu)
init_cpu(cpu);
/* Note the use of the double underscored version of the API */
__register_cpu_notifier(&foobar_cpu_notifier);
cpu_notifier_register_done();
Fix the code in net/core/flow.c by using this latter form of callback
registration.
Cc: Li RongQing <roy.qing.li@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: netdev@vger.kernel.org
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
---
net/core/flow.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/net/core/flow.c b/net/core/flow.c
index dfa602c..9a2151f 100644
--- a/net/core/flow.c
+++ b/net/core/flow.c
@@ -456,6 +456,8 @@ static int __init flow_cache_init(struct flow_cache *fc)
if (!fc->percpu)
return -ENOMEM;
+ cpu_notifier_register_begin();
+
for_each_online_cpu(i) {
if (flow_cache_cpu_prepare(fc, i))
goto err;
@@ -463,7 +465,9 @@ static int __init flow_cache_init(struct flow_cache *fc)
fc->hotcpu_notifier = (struct notifier_block){
.notifier_call = flow_cache_cpu,
};
- register_hotcpu_notifier(&fc->hotcpu_notifier);
+ __register_hotcpu_notifier(&fc->hotcpu_notifier);
+
+ cpu_notifier_register_done();
setup_timer(&fc->rnd_timer, flow_cache_new_hashrnd,
(unsigned long) fc);
@@ -479,6 +483,8 @@ err:
fcp->hash_table = NULL;
}
+ cpu_notifier_register_done();
+
free_percpu(fc->percpu);
fc->percpu = NULL;
next prev parent reply other threads:[~2014-03-10 20:43 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-10 20:33 [PATCH v3 00/52] CPU hotplug: Fix issues with callback registration Srivatsa S. Bhat
2014-03-10 20:34 ` [PATCH v3 01/52] CPU hotplug: Add lockdep annotations to get/put_online_cpus() Srivatsa S. Bhat
2014-03-10 20:34 ` [PATCH v3 02/52] CPU hotplug: Provide lockless versions of callback registration functions Srivatsa S. Bhat
2014-03-10 20:34 ` [PATCH v3 03/52] Doc/cpu-hotplug: Specify race-free way to register CPU hotplug callbacks Srivatsa S. Bhat
2014-03-10 20:34 ` [PATCH v3 04/52] CPU hotplug, perf: Fix CPU hotplug callback registration Srivatsa S. Bhat
2014-03-10 20:34 ` [PATCH v3 05/52] ia64, salinfo: Fix " Srivatsa S. Bhat
2014-03-10 20:34 ` [PATCH v3 06/52] ia64, palinfo: Fix CPU " Srivatsa S. Bhat
2014-03-10 20:34 ` [PATCH v3 07/52] ia64, topology: " Srivatsa S. Bhat
2014-03-10 20:35 ` [PATCH v3 08/52] ia64, err-inject: " Srivatsa S. Bhat
2014-03-10 20:35 ` [PATCH v3 09/52] arm, hw-breakpoint: " Srivatsa S. Bhat
2014-03-10 20:35 ` [PATCH v3 10/52] arm, kvm: " Srivatsa S. Bhat
2014-03-12 23:21 ` Christoffer Dall
2014-03-14 5:43 ` Srivatsa S. Bhat
2014-03-14 19:10 ` Christoffer Dall
2014-03-18 10:23 ` [UPDATED PATCH " Srivatsa S. Bhat
2014-03-18 22:08 ` Christoffer Dall
2014-03-10 20:35 ` [PATCH v3 11/52] s390, cacheinfo: " Srivatsa S. Bhat
2014-03-10 20:35 ` [PATCH v3 12/52] s390, smp: " Srivatsa S. Bhat
2014-03-10 20:36 ` [PATCH v3 13/52] sparc, sysfs: " Srivatsa S. Bhat
2014-03-10 20:36 ` [PATCH v3 14/52] powerpc, " Srivatsa S. Bhat
2014-03-10 20:36 ` [PATCH v3 15/52] x86, msr: " Srivatsa S. Bhat
2014-03-10 20:36 ` [PATCH v3 16/52] x86, cpuid: " Srivatsa S. Bhat
2014-03-10 20:36 ` [PATCH v3 17/52] x86, vsyscall: " Srivatsa S. Bhat
2014-03-10 20:36 ` [PATCH v3 18/52] x86, intel, uncore: " Srivatsa S. Bhat
2014-03-10 20:37 ` [PATCH v3 19/52] x86, mce: " Srivatsa S. Bhat
2014-03-10 20:37 ` [PATCH v3 20/52] x86, therm_throt.c: " Srivatsa S. Bhat
2014-03-10 20:37 ` [PATCH v3 21/52] x86, therm_throt.c: Remove unused therm_cpu_lock Srivatsa S. Bhat
2014-03-10 20:37 ` [PATCH v3 22/52] x86, amd, ibs: Fix CPU hotplug callback registration Srivatsa S. Bhat
2014-03-10 20:37 ` [PATCH v3 23/52] x86, intel, cacheinfo: " Srivatsa S. Bhat
2014-03-10 20:38 ` [PATCH v3 24/52] x86, intel, rapl: " Srivatsa S. Bhat
2014-03-10 20:38 ` [PATCH v3 25/52] x86, amd, uncore: " Srivatsa S. Bhat
2014-03-10 20:38 ` [PATCH v3 26/52] x86, hpet: " Srivatsa S. Bhat
2014-03-10 20:38 ` [PATCH v3 27/52] x86, pci, amd-bus: " Srivatsa S. Bhat
2014-03-10 20:38 ` [PATCH v3 28/52] x86, oprofile, nmi: " Srivatsa S. Bhat
2014-03-10 20:39 ` [PATCH v3 29/52] x86, kvm: " Srivatsa S. Bhat
2014-03-10 20:39 ` [PATCH v3 30/52] arm64, hw_breakpoint.c: " Srivatsa S. Bhat
2014-03-10 20:39 ` [PATCH v3 31/52] arm64, debug-monitors: " Srivatsa S. Bhat
2014-03-10 20:39 ` [PATCH v3 32/52] powercap, intel-rapl: " Srivatsa S. Bhat
2014-03-12 22:27 ` Jacob Pan
2014-03-10 20:39 ` [PATCH v3 33/52] scsi, bnx2i: " Srivatsa S. Bhat
2014-03-10 20:39 ` [PATCH v3 34/52] scsi, bnx2fc: " Srivatsa S. Bhat
2014-03-10 20:39 ` [PATCH v3 35/52] scsi, fcoe: " Srivatsa S. Bhat
2014-03-10 20:39 ` [PATCH v3 36/52] zsmalloc: " Srivatsa S. Bhat
2014-03-14 6:41 ` Minchan Kim
2014-03-10 20:40 ` [PATCH v3 37/52] acpi-cpufreq: " Srivatsa S. Bhat
2014-03-10 20:40 ` [PATCH v3 38/52] drivers/base/topology.c: " Srivatsa S. Bhat
2014-03-10 20:40 ` [PATCH v3 39/52] clocksource, dummy-timer: " Srivatsa S. Bhat
2014-03-10 20:40 ` [PATCH v3 40/52] intel-idle: " Srivatsa S. Bhat
2014-03-10 20:40 ` [PATCH v3 41/52] oprofile, nmi-timer: " Srivatsa S. Bhat
2014-03-10 20:40 ` [PATCH v3 42/52] octeon, watchdog: " Srivatsa S. Bhat
2014-03-10 20:40 ` [PATCH v3 43/52] thermal, x86-pkg-temp: " Srivatsa S. Bhat
2014-03-10 20:41 ` [PATCH v3 44/52] hwmon, coretemp: " Srivatsa S. Bhat
2014-03-10 20:41 ` [PATCH v3 45/52] hwmon, via-cputemp: " Srivatsa S. Bhat
2014-03-10 20:41 ` [PATCH v3 46/52] xen, balloon: " Srivatsa S. Bhat
2014-03-10 20:41 ` [PATCH v3 47/52] trace, ring-buffer: " Srivatsa S. Bhat
2014-03-10 20:42 ` [PATCH v3 48/52] profile: " Srivatsa S. Bhat
2014-03-10 20:42 ` [PATCH v3 49/52] mm, vmstat: " Srivatsa S. Bhat
2014-03-10 20:42 ` [PATCH v3 50/52] mm, zswap: " Srivatsa S. Bhat
2014-03-10 20:42 ` Srivatsa S. Bhat [this message]
2014-03-10 20:42 ` [PATCH v3 52/52] net/iucv/iucv.c: " Srivatsa S. Bhat
2014-03-11 0:31 ` [PATCH v3 00/52] CPU hotplug: Fix issues with " Rafael J. Wysocki
2014-03-11 22:07 ` Andrew Morton
2014-03-12 20:48 ` Srivatsa S. Bhat
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