linux-kernel - Re: [PATCH 2/6] irq_work: Implement remote queueing

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]

Date:	Wed, 25 Jun 2014 11:39:44 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>
Cc:	Stephen Warren <swarren@...dotorg.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Eric Dumazet <eric.dumazet@...il.com>,
	Ingo Molnar <mingo@...nel.org>,
	Kevin Hilman <khilman@...aro.org>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	"linux-next@...r.kernel.org" <linux-next@...r.kernel.org>
Subject: Re: [PATCH 2/6] irq_work: Implement remote queueing

On Wed, Jun 25, 2014 at 11:36:57AM +0200, Peter Zijlstra wrote:
> On Wed, Jun 25, 2014 at 12:07:05PM +0530, Srivatsa S. Bhat wrote:
> > I don't think irqs_disabled() is the problematic condition, since
> > hotplug_cfg() invokes irq_work_run() from CPU_DYING context (which has
> > irqs disabled). I guess you meant to remove the in_irq() check inside
> > irq_work_run() instead?
> 
> Yes, clearly I should not get up at 6am.. :-) Let me go do a new one.

---
Subject: irq_work: Remove BUG_ON in irq_work_run()
From: Peter Zijlstra <peterz@...radead.org>
Date: Wed Jun 25 07:13:07 CEST 2014

Because of a collision with 8d056c48e486 ("CPU hotplug, smp: flush any
pending IPI callbacks before CPU offline"), which ends up calling
hotplug_cfd()->flush_smp_call_function_queue()->irq_work_run(), which
is not from IRQ context.

Cc: Frederic Weisbecker <fweisbec@...il.com>
Reported-by: Stephen Warren <swarren@...dotorg.org>
Signed-off-by: Peter Zijlstra <peterz@...radead.org>
Link: http://lkml.kernel.org/n/tip-busatzs2gvz4v62258agipuf@git.kernel.org
---
 kernel/irq_work.c |   12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

Index: linux-2.6/kernel/irq_work.c
===================================================================
--- linux-2.6.orig/kernel/irq_work.c
+++ linux-2.6/kernel/irq_work.c
@@ -160,21 +160,11 @@ static void irq_work_run_list(struct lli
 	}
 }
 
-static void __irq_work_run(void)
+static void irq_work_run(void)
 {
 	irq_work_run_list(&__get_cpu_var(raised_list));
 	irq_work_run_list(&__get_cpu_var(lazy_list));
 }
-
-/*
- * Run the irq_work entries on this cpu. Requires to be ran from hardirq
- * context with local IRQs disabled.
- */
-void irq_work_run(void)
-{
-	BUG_ON(!in_irq());
-	__irq_work_run();
-}
 EXPORT_SYMBOL_GPL(irq_work_run);
 
 /*
--
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/