From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sebastian Andrzej Siewior Subject: Re: Warning: tree_plugin.h:310 rcu_note_context_switch Date: Thu, 30 Nov 2017 17:23:42 +0100 Message-ID: <20171130162342.GF11362@linutronix.de> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Cc: linux-rt-users@vger.kernel.org To: Daniel Wagner Return-path: Received: from Galois.linutronix.de ([146.0.238.70]:45897 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750742AbdK3QXo (ORCPT ); Thu, 30 Nov 2017 11:23:44 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-rt-users-owner@vger.kernel.org List-ID: On 2017-11-29 17:29:59 [+0100], Daniel Wagner wrote: > Hi, Hi. > I was playing with cyclictest and pi_stress on x86_64 with v4.14-rt1 and got > a greeting. > > Unfortunately, I can't remember the exact the cyclictest arguments but it was either > > "cyclictest -S -p 80" or "cyclictest -t -p 80" > > [ 142.205742] ------------[ cut here ]------------ > [ 142.205754] WARNING: CPU: 0 PID: 1552 at /home/wagi/work/rt/linux-rt/kernel/rcu/tree_plugin.h:310 rcu_note_context_switch+0x2c7/0x560 > [ 142.205790] Call Trace: > [ 142.205798] __schedule+0x72/0x550 > [ 142.205803] schedule+0x38/0xd0 > [ 142.205807] hrtimer_wait_for_timer+0x44/0x80 > [ 142.205812] ? wait_woken+0x80/0x80 > [ 142.205816] SyS_timer_delete+0xb1/0x160 > [ 142.205821] entry_SYSCALL_64_fastpath+0x13/0x94 This isn't "new". Paul added a warning recently to check if we schedule out within a rcu_read() section. We do this here while waiting for the timer to complete… > Thanks, > Daniel Sebastian