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
| ||
|
Date: Fri, 14 Feb 2014 13:27:05 +0530 From: "Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com> To: paulus@...ba.org, oleg@...hat.com, mingo@...nel.org, rusty@...tcorp.com.au, peterz@...radead.org, tglx@...utronix.de, akpm@...ux-foundation.org Cc: paulmck@...ux.vnet.ibm.com, tj@...nel.org, walken@...gle.com, ego@...ux.vnet.ibm.com, linux@....linux.org.uk, rjw@...ysocki.net, linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org, srivatsa.bhat@...ux.vnet.ibm.com, Robert Love <robert.w.love@...el.com>, "James E.J. Bottomley" <JBottomley@...allels.com>, Ingo Molnar <mingo@...nel.org>, fcoe-devel@...n-fcoe.org, linux-scsi@...r.kernel.org, "Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com> Subject: [PATCH v2 35/52] scsi, fcoe: Fix CPU hotplug callback registration 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 fcoe code in scsi by using this latter form of callback registration. Cc: Robert Love <robert.w.love@...el.com> Cc: "James E.J. Bottomley" <JBottomley@...allels.com> Cc: Ingo Molnar <mingo@...nel.org> Cc: fcoe-devel@...n-fcoe.org Cc: linux-scsi@...r.kernel.org Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@...ux.vnet.ibm.com> --- drivers/scsi/fcoe/fcoe.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/fcoe/fcoe.c b/drivers/scsi/fcoe/fcoe.c index f317000..d5e105b 100644 --- a/drivers/scsi/fcoe/fcoe.c +++ b/drivers/scsi/fcoe/fcoe.c @@ -2633,14 +2633,18 @@ static int __init fcoe_init(void) skb_queue_head_init(&p->fcoe_rx_list); } + cpu_notifier_register_begin(); + for_each_online_cpu(cpu) fcoe_percpu_thread_create(cpu); /* Initialize per CPU interrupt thread */ - rc = register_hotcpu_notifier(&fcoe_cpu_notifier); + rc = __register_hotcpu_notifier(&fcoe_cpu_notifier); if (rc) goto out_free; + cpu_notifier_register_done(); + /* Setup link change notification */ fcoe_dev_setup(); @@ -2655,6 +2659,9 @@ out_free: for_each_online_cpu(cpu) { fcoe_percpu_thread_destroy(cpu); } + + cpu_notifier_register_done(); + mutex_unlock(&fcoe_config_mutex); destroy_workqueue(fcoe_wq); return rc; @@ -2687,11 +2694,15 @@ static void __exit fcoe_exit(void) } rtnl_unlock(); - unregister_hotcpu_notifier(&fcoe_cpu_notifier); + cpu_notifier_register_begin(); for_each_online_cpu(cpu) fcoe_percpu_thread_destroy(cpu); + __unregister_hotcpu_notifier(&fcoe_cpu_notifier); + + cpu_notifier_register_done(); + mutex_unlock(&fcoe_config_mutex); /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists