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Date: Tue, 22 Oct 2013 22:46:32 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Fengguang Wu <fengguang.wu@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>, linux-kernel@vger.kernel.org
Subject: Re: [sched] WARNING: CPU: 0 PID: 3166 at kernel/cpu.c:84
 put_online_cpus()
Message-ID: <20131022204632.GD2490@laptop.programming.kicks-ass.net>
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On Sat, Oct 19, 2013 at 08:51:29AM +0800, Fengguang Wu wrote:
> Greetings,
> [   58.695502] ------------[ cut here ]------------
> [   58.697835] WARNING: CPU: 0 PID: 3166 at kernel/cpu.c:84 put_online_cpus+0x43/0x70()
> [   58.702423] Modules linked in:
> [   58.704404] CPU: 0 PID: 3166 Comm: trinity-child0 Not tainted 3.12.0-rc5-01882-gf3db366 #1172
> [   58.708530] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
> [   58.710992]  0000000000000000 ffff88000acfbe50 ffffffff81a24643 0000000000000000
> [   58.715410]  ffff88000acfbe88 ffffffff810c3e6b ffffffff810c3fef 0000000000000000
> [   58.719826]  0000000000000000 0000000000006ee0 0000000000000ffc ffff88000acfbe98
> [   58.724348] Call Trace:
> [   58.726190]  [<ffffffff81a24643>] dump_stack+0x4d/0x66
> [   58.728531]  [<ffffffff810c3e6b>] warn_slowpath_common+0x7f/0x98
> [   58.731069]  [<ffffffff810c3fef>] ? put_online_cpus+0x43/0x70
> [   58.733664]  [<ffffffff810c3f32>] warn_slowpath_null+0x1a/0x1c
> [   58.736258]  [<ffffffff810c3fef>] put_online_cpus+0x43/0x70
> [   58.738686]  [<ffffffff810efd59>] sched_setaffinity+0x7d/0x1f9
> [   58.741210]  [<ffffffff810efce1>] ? sched_setaffinity+0x5/0x1f9
> [   58.743775]  [<ffffffff81a2f724>] ? _raw_spin_unlock_irq+0x2c/0x3e
> [   58.746417]  [<ffffffff810c7012>] ? do_setitimer+0x194/0x1f5
> [   58.748899]  [<ffffffff810eff37>] SyS_sched_setaffinity+0x62/0x71
> [   58.751481]  [<ffffffff81a373a9>] system_call_fastpath+0x16/0x1b
> [   58.754070] ---[ end trace 034818a1f6f06868 ]---
> [   58.757521] ------------[ cut here ]------------

Duh.. must've been blind or so..

Does this make it go away

---
 kernel/sched/core.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index c06b8d3..7c61f31 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3716,7 +3716,6 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
 	p = find_process_by_pid(pid);
 	if (!p) {
 		rcu_read_unlock();
-		put_online_cpus();
 		return -ESRCH;
 	}