[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <CAJZ5v0gyPtX=ksCibo2ZN_BztCqUn9KRtRu+gsJ5KetB_1MwEQ@mail.gmail.com>
Date: Fri, 29 Jul 2022 16:59:50 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Michel Lespinasse <michel@...pinasse.org>
Cc: "Paul E. McKenney" <paulmck@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Richard Henderson <rth@...ddle.net>,
Ivan Kokshaysky <ink@...assic.park.msu.ru>,
Matt Turner <mattst88@...il.com>, vgupta@...nel.org,
Russell King - ARM Linux <linux@...linux.org.uk>,
ulli.kroll@...glemail.com,
Linus Walleij <linus.walleij@...aro.org>,
Shawn Guo <shawnguo@...nel.org>,
Sascha Hauer <s.hauer@...gutronix.de>,
Sascha Hauer <kernel@...gutronix.de>,
Fabio Estevam <festevam@...il.com>,
dl-linux-imx <linux-imx@....com>,
Tony Lindgren <tony@...mide.com>,
Kevin Hilman <khilman@...nel.org>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>, Guo Ren <guoren@...nel.org>,
bcain@...cinc.com, Huacai Chen <chenhuacai@...nel.org>,
kernel@...0n.name, Geert Uytterhoeven <geert@...ux-m68k.org>,
sammy@...my.net, Michal Simek <monstr@...str.eu>,
Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
dinguyen@...nel.org, jonas@...thpole.se,
stefan.kristiansson@...nalahti.fi,
Stafford Horne <shorne@...il.com>,
James Bottomley <James.Bottomley@...senpartnership.com>,
Helge Deller <deller@....de>,
Michael Ellerman <mpe@...erman.id.au>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Paul Walmsley <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>,
Albert Ou <aou@...s.berkeley.edu>,
Heiko Carstens <hca@...ux.ibm.com>,
Vasily Gorbik <gor@...ux.ibm.com>,
Alexander Gordeev <agordeev@...ux.ibm.com>,
Christian Borntraeger <borntraeger@...ux.ibm.com>,
Sven Schnelle <svens@...ux.ibm.com>,
Yoshinori Sato <ysato@...rs.sourceforge.jp>,
Rich Felker <dalias@...c.org>,
David Miller <davem@...emloft.net>,
Richard Weinberger <richard@....at>,
anton.ivanov@...bridgegreys.com,
Johannes Berg <johannes@...solutions.net>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
Dave Hansen <dave.hansen@...ux.intel.com>,
"the arch/x86 maintainers" <x86@...nel.org>,
"H. Peter Anvin" <hpa@...or.com>, acme@...nel.org,
Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
jolsa@...nel.org, namhyung@...nel.org,
Juergen Gross <jgross@...e.com>, srivatsa@...il.mit.edu,
amakhalov@...are.com, pv-drivers@...are.com,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
Chris Zankel <chris@...kel.net>,
Max Filippov <jcmvbkbc@...il.com>,
"Rafael J. Wysocki" <rafael@...nel.org>,
Len Brown <lenb@...nel.org>, Pavel Machek <pavel@....cz>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Michael Turquette <mturquette@...libre.com>,
Stephen Boyd <sboyd@...nel.org>,
Daniel Lezcano <daniel.lezcano@...aro.org>,
Lorenzo Pieralisi <lpieralisi@...nel.org>,
Sudeep Holla <sudeep.holla@....com>,
Andy Gross <agross@...nel.org>,
Bjorn Andersson <bjorn.andersson@...aro.org>,
Anup Patel <anup@...infault.org>,
Thierry Reding <thierry.reding@...il.com>,
Jon Hunter <jonathanh@...dia.com>,
Jacob Pan <jacob.jun.pan@...ux.intel.com>,
Arnd Bergmann <arnd@...db.de>,
Yury Norov <yury.norov@...il.com>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Rasmus Villemoes <linux@...musvillemoes.dk>,
Steven Rostedt <rostedt@...dmis.org>,
Petr Mladek <pmladek@...e.com>, senozhatsky@...omium.org,
John Ogness <john.ogness@...utronix.de>,
Frederic Weisbecker <frederic@...nel.org>,
quic_neeraju@...cinc.com, Josh Triplett <josh@...htriplett.org>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Lai Jiangshan <jiangshanlai@...il.com>,
Joel Fernandes <joel@...lfernandes.org>,
Juri Lelli <juri.lelli@...hat.com>,
Vincent Guittot <vincent.guittot@...aro.org>,
Dietmar Eggemann <dietmar.eggemann@....com>,
Benjamin Segall <bsegall@...gle.com>,
Mel Gorman <mgorman@...e.de>,
Daniel Bristot de Oliveira <bristot@...hat.com>,
vschneid@...hat.com, jpoimboe@...nel.org,
linux-alpha@...r.kernel.org,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
linux-snps-arc@...ts.infradead.org,
Linux ARM <linux-arm-kernel@...ts.infradead.org>,
Linux OMAP Mailing List <linux-omap@...r.kernel.org>,
linux-csky@...r.kernel.org, linux-hexagon@...r.kernel.org,
linux-ia64@...r.kernel.org,
linux-m68k <linux-m68k@...ts.linux-m68k.org>,
"open list:BROADCOM NVRAM DRIVER" <linux-mips@...r.kernel.org>,
openrisc@...ts.librecores.org,
Parisc List <linux-parisc@...r.kernel.org>,
linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
linux-riscv <linux-riscv@...ts.infradead.org>,
linux-s390@...r.kernel.org,
Linux-sh list <linux-sh@...r.kernel.org>,
sparclinux@...r.kernel.org, linux-um@...ts.infradead.org,
linux-perf-users@...r.kernel.org,
virtualization@...ts.linux-foundation.org,
xen-devel@...ts.xenproject.org, linux-xtensa@...ux-xtensa.org,
ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
Linux PM <linux-pm@...r.kernel.org>,
linux-clk <linux-clk@...r.kernel.org>,
linux-arm-msm <linux-arm-msm@...r.kernel.org>,
linux-tegra <linux-tegra@...r.kernel.org>,
linux-arch <linux-arch@...r.kernel.org>, rcu@...r.kernel.org,
rh0@...com
Subject: Re: [PATCH 04/36] cpuidle,intel_idle: Fix CPUIDLE_FLAG_IRQ_ENABLE
On Fri, Jul 29, 2022 at 12:25 PM Michel Lespinasse
<michel@...pinasse.org> wrote:
>
> On Thu, Jul 28, 2022 at 10:20:53AM -0700, Paul E. McKenney wrote:
> > On Mon, Jul 25, 2022 at 12:43:06PM -0700, Michel Lespinasse wrote:
> > > On Wed, Jun 08, 2022 at 04:27:27PM +0200, Peter Zijlstra wrote:
> > > > Commit c227233ad64c ("intel_idle: enable interrupts before C1 on
> > > > Xeons") wrecked intel_idle in two ways:
> > > >
> > > > - must not have tracing in idle functions
> > > > - must return with IRQs disabled
> > > >
> > > > Additionally, it added a branch for no good reason.
> > > >
> > > > Fixes: c227233ad64c ("intel_idle: enable interrupts before C1 on Xeons")
> > > > Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
> > >
> > > After this change was introduced, I am seeing "WARNING: suspicious RCU
> > > usage" when booting a kernel with debug options compiled in. Please
> > > see the attached dmesg output. The issue starts with commit 32d4fd5751ea
> > > and is still present in v5.19-rc8.
> > >
> > > I'm not sure, is this too late to fix or revert in v5.19 final ?
> >
> > I finally got a chance to take a quick look at this.
> >
> > The rcu_eqs_exit() function is making a lockdep complaint about
> > being invoked with interrupts enabled. This function is called from
> > rcu_idle_exit(), which is an expected code path from cpuidle_enter_state()
> > via its call to rcu_idle_exit(). Except that rcu_idle_exit() disables
> > interrupts before invoking rcu_eqs_exit().
> >
> > The only other call to rcu_idle_exit() does not disable interrupts,
> > but it is via rcu_user_exit(), which would be a very odd choice for
> > cpuidle_enter_state().
> >
> > It seems unlikely, but it might be that it is the use of local_irq_save()
> > instead of raw_local_irq_save() within rcu_idle_exit() that is causing
> > the trouble. If this is the case, then the commit shown below would
> > help. Note that this commit removes the warning from lockdep, so it
> > is necessary to build the kernel with CONFIG_RCU_EQS_DEBUG=y to enable
> > equivalent debugging.
> >
> > Could you please try your test with the -rce commit shown below applied?
>
> Thanks for looking into it.
>
> After checking out Peter's commit 32d4fd5751ea,
> cherry picking your commit ed4ae5eff4b3,
> and setting CONFIG_RCU_EQS_DEBUG=y in addition of my usual debug config,
> I am now seeing this a few seconds into the boot:
>
> [ 3.010650] ------------[ cut here ]------------
> [ 3.010651] WARNING: CPU: 0 PID: 0 at kernel/sched/clock.c:397 sched_clock_tick+0x27/0x60
> [ 3.010657] Modules linked in:
> [ 3.010660] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.19.0-rc1-test-00005-g1be22fea0611 #1
> [ 3.010662] Hardware name: LENOVO 30BFS44D00/1036, BIOS S03KT51A 01/17/2022
> [ 3.010663] RIP: 0010:sched_clock_tick+0x27/0x60
> [ 3.010665] Code: 1f 40 00 53 eb 02 5b c3 66 90 8b 05 2f c3 40 01 85 c0 74 18 65 8b 05 60 88 8f 4e 85 c0 75 0d 65 8b 05 a9 85 8f 4e 85 c0 74 02 <0f> 0b e8 e2 6c 89 00 48 c7 c3 40 d5 02 00
> 89 c0 48 03 1c c5 c0 98
> [ 3.010667] RSP: 0000:ffffffffb2803e28 EFLAGS: 00010002
> [ 3.010670] RAX: 0000000000000001 RBX: ffffc8ce7fa07060 RCX: 0000000000000001
> [ 3.010671] RDX: 0000000000000000 RSI: ffffffffb268dd21 RDI: ffffffffb269ab13
> [ 3.010673] RBP: 0000000000000001 R08: ffffffffffc300d5 R09: 000000000002be80
> [ 3.010674] R10: 000003625b53183a R11: ffffa012b802b7a4 R12: ffffffffb2aa9e80
> [ 3.010675] R13: ffffffffb2aa9e00 R14: 0000000000000001 R15: 0000000000000000
> [ 3.010677] FS: 0000000000000000(0000) GS:ffffa012b8000000(0000) knlGS:0000000000000000
> [ 3.010678] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 3.010680] CR2: ffffa012f81ff000 CR3: 0000000c99612001 CR4: 00000000003706f0
> [ 3.010681] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 3.010682] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [ 3.010683] Call Trace:
> [ 3.010685] <TASK>
> [ 3.010688] cpuidle_enter_state+0xb7/0x4b0
> [ 3.010694] cpuidle_enter+0x29/0x40
> [ 3.010697] do_idle+0x1d4/0x210
> [ 3.010702] cpu_startup_entry+0x19/0x20
> [ 3.010704] rest_init+0x117/0x1a0
> [ 3.010708] arch_call_rest_init+0xa/0x10
> [ 3.010711] start_kernel+0x6d8/0x6ff
> [ 3.010716] secondary_startup_64_no_verify+0xce/0xdb
> [ 3.010728] </TASK>
> [ 3.010729] irq event stamp: 44179
> [ 3.010730] hardirqs last enabled at (44179): [<ffffffffb2000ccb>] asm_sysvec_apic_timer_interrupt+0x1b/0x20
> [ 3.010734] hardirqs last disabled at (44177): [<ffffffffb22003f0>] __do_softirq+0x3f0/0x498
> [ 3.010736] softirqs last enabled at (44178): [<ffffffffb2200332>] __do_softirq+0x332/0x498
> [ 3.010738] softirqs last disabled at (44171): [<ffffffffb16c760b>] irq_exit_rcu+0xab/0xf0
> [ 3.010741] ---[ end trace 0000000000000000 ]---
Can you please give this patch a go:
https://patchwork.kernel.org/project/linux-pm/patch/Yt/AxPFi88neW7W5@e126311.manchester.arm.com/
?
Powered by blists - more mailing lists