From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752495AbdBAPtS (ORCPT ); Wed, 1 Feb 2017 10:49:18 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:37366 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751173AbdBAPtR (ORCPT ); Wed, 1 Feb 2017 10:49:17 -0500 Date: Wed, 1 Feb 2017 07:49:09 -0800 From: "Paul E. McKenney" To: Dmitry Vyukov Cc: Ingo Molnar , "H. Peter Anvin" , LKML , Thomas Gleixner , linux-tip-commits@vger.kernel.org Subject: Re: [tip:core/rcu] lockdep: Make RCU suspicious-access splats use pr_err Reply-To: paulmck@linux.vnet.ibm.com References: <20170131085105.GA27019@gmail.com> <20170131091757.GA3940@gmail.com> <20170131154945.GF30506@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 17020115-0012-0000-0000-00001384E64A X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00006537; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000201; SDB=6.00815747; UDB=6.00398282; IPR=6.00593189; BA=6.00005108; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00014137; XFM=3.00000011; UTC=2017-02-01 15:49:10 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17020115-0013-0000-0000-00004B07B219 Message-Id: <20170201154909.GR30506@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-02-01_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1612050000 definitions=main-1702010158 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 01, 2017 at 12:07:36PM +0100, Dmitry Vyukov wrote: > On Tue, Jan 31, 2017 at 4:49 PM, Paul E. McKenney > wrote: > > On Tue, Jan 31, 2017 at 10:17:57AM +0100, Ingo Molnar wrote: > >> > >> * Dmitry Vyukov wrote: > >> > >> > FWIW my vote is for: > >> > > >> > ========================== > >> > WARNING: suspicious RCU usage > >> > ========================== > >> > >> For heaven's sake make it: > >> > >> ============================= > >> WARNING: suspicious RCU usage > >> ============================= > >> > >> (Note the length of the start/stop lines.) > > > > Like this? > > > > Thanx, Paul > > > > ------------------------------------------------------------------------ > > > > commit 45a2b28bb464a88ea886759c23a3cfa9b9b10055 > > Author: Paul E. McKenney > > Date: Tue Jan 31 07:45:13 2017 -0800 > > > > lockdep: Use "WARNING" tag on lockdep splats > > > > This commit changes lockdep splats to begin lines with "WARNING" and > > to use pr_warn() instead of printk(). This change eases scripted > > analysis of kernel console output. > > > > Reported-by: Dmitry Vyukov > > Reported-by: Ingo Molnar > > Signed-off-by: Paul E. McKenney > > > > diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c > > index d9a698e8458f..330648980789 100644 > > --- a/kernel/locking/lockdep.c > > +++ b/kernel/locking/lockdep.c [ . . . ] > > @@ -1480,11 +1480,11 @@ print_bad_irq_dependency(struct task_struct *curr, > > return 0; > > > > printk("\n"); > > - printk("======================================================\n"); > > - printk("[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", > > + pr_warn("=================================================\n"); > > + pr_warn("WARNING: %s-safe -> %s-unsafe lock order detected\n", > > The previous === line was 6 chars longer than the message (for %s expansion). > Not sure if it matters much. I am only seeing a 4-character difference, but good point. I restored the extra characters here an on the line below. > > irqclass, irqclass); > > print_kernel_ident(); > > - printk("------------------------------------------------------\n"); > > + pr_warn("-------------------------------------------------\n"); > > printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", > > curr->comm, task_pid_nr(curr), > > curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, [ . . . ] > > @@ -3168,10 +3168,10 @@ print_lock_nested_lock_not_held(struct task_struct *curr, > > return 0; > > > > printk("\n"); > > - printk("==================================\n"); > > - printk("[ BUG: Nested lock was not taken ]\n"); > > + pr_warn("==================================\n"); > > + pr_warn("WARNING: Nested lock was not taken\n"); > > Maybe s/Nested/nested/ of consistency? I don't feel strongly either way. What do others think? > > print_kernel_ident(); > > - printk("----------------------------------\n"); > > + pr_warn("----------------------------------\n"); > > > > printk("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr)); > > print_lock(hlock); [ . . . ] > > diff --git a/kernel/locking/rtmutex-debug.c b/kernel/locking/rtmutex-debug.c > > index 62b6cee8ea7f..7f8a9e2ced6e 100644 > > --- a/kernel/locking/rtmutex-debug.c > > +++ b/kernel/locking/rtmutex-debug.c > > @@ -101,10 +101,11 @@ void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter) > > return; > > } > > > > - printk("\n============================================\n"); > > - printk( "[ BUG: circular locking deadlock detected! ]\n"); > > - printk("%s\n", print_tainted()); > > - printk( "--------------------------------------------\n"); > > + pr_warn("\n"); > > + pr_warn("============================================\n"); > > + pr_warn("WARNING: circular locking deadlock detected!\n"); > > + pr_warn("%s\n", print_tainted()); > > + pr_warn("--------------------------------------------\n"); > > printk("%s/%d is deadlocking current task %s/%d\n\n", > > task->comm, task_pid_nr(task), > > current->comm, task_pid_nr(current)); > > Acked-by: Dmitry Vyukov Applied, thank you! Thanx, Paul