From: Peter Zijlstra <peterz@infradead.org>
To: Marco Elver <elver@google.com>
Cc: linux-s390@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
bigeasy@linutronix.de, the arch/x86 maintainers <x86@kernel.org>,
heiko.carstens@de.ibm.com, LKML <linux-kernel@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
"David S. Miller" <davem@davemloft.net>, Qian Cai <cai@lca.pw>,
"Ahmed S. Darwish" <a.darwish@linutronix.de>,
sparclinux@vger.kernel.org, linux@armlinux.org.uk,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will@kernel.org>, Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH v4 7/8] lockdep: Change hardirq{s_enabled,_context} to per-cpu variables
Date: Tue, 23 Jun 2020 21:41:32 +0200 [thread overview]
Message-ID: <20200623194132.GC2483@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20200623191335.GA86296@elver.google.com>
On Tue, Jun 23, 2020 at 09:13:35PM +0200, Marco Elver wrote:
> I see the below report when I boot with your branch + KCSAN and
> PROVE_LOCKING. config attached. Trying to make sense of what's
> happening.
Ah, I was still playing with tip/master + PROVE_LOCKING + KCSAN and
slowly removing parts of that annotation patch to see what would come
unstuck.
I think I just hit a genuine but unavoidable lockdep report on
report_lock.
> ------ >8 ------
>
> [ 10.182354] ------------[ cut here ]------------
> [ 10.183058] WARNING: CPU: 7 PID: 136 at kernel/locking/lockdep.c:398 lockdep_hardirqs_on_prepare+0x1c6/0x270
> [ 10.184347] Modules linked in:
> [ 10.184771] CPU: 7 PID: 136 Comm: systemd-journal Not tainted 5.8.0-rc1+ #3
> [ 10.185706] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014
> [ 10.186821] RIP: 0010:lockdep_hardirqs_on_prepare+0x1c6/0x270
> [ 10.187594] Code: 75 28 65 48 8b 04 25 28 00 00 00 48 3b 44 24 08 0f 85 b9 00 00 00 48 83 c4 10 5b 41 5e 41 5f c3 65 48 ff 05 d4 24 4e 75 eb d8 <0f> 0b 90 41 c7 86 c4 08 00 00 00 00 00 00 eb c8 e8 65 09 71 01 85
> [ 10.190203] RSP: 0018:ffffa7ee802b7848 EFLAGS: 00010017
> [ 10.190989] RAX: 0000000000000001 RBX: ffff955e92a34ab0 RCX: 0000000000000001
> [ 10.192053] RDX: 0000000000000006 RSI: ffff955e92a34a88 RDI: ffff955e92a341c0
> [ 10.193117] RBP: ffffa7ee802b7be8 R08: 0000000000000000 R09: 0000ffffffffffff
> [ 10.194186] R10: 0000ffffffffffff R11: 0000ffff8d07e268 R12: 0000000000000001
> [ 10.195249] R13: ffffffff8e41bb10 R14: ffff955e92a341c0 R15: 0000000000000001
> [ 10.196312] FS: 00007fd6862aa8c0(0000) GS:ffff955e9fd80000(0000) knlGS:0000000000000000
> [ 10.197513] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 10.198373] CR2: 00007fd6837dd000 CR3: 0000000812acc001 CR4: 0000000000760ee0
> [ 10.199436] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 10.200494] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [ 10.201554] PKRU: 55555554
> [ 10.201967] Call Trace:
> [ 10.202348] ? _raw_spin_unlock_irqrestore+0x40/0x70
> [ 10.203093] trace_hardirqs_on+0x56/0x60 <----- enter IRQ flags tracing code?
> [ 10.203686] _raw_spin_unlock_irqrestore+0x40/0x70 <----- take report_lock
> [ 10.204406] prepare_report+0x11f/0x150
> [ 10.204986] kcsan_report+0xca/0x6c0 <----- generating a KCSAN report
> [ 10.212669] kcsan_found_watchpoint+0xe5/0x110
That appears to be warning about a lockdep_recursion underflow, weird.
I'll go stare at it.
next prev parent reply other threads:[~2020-06-23 19:44 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-23 8:36 [PATCH v4 0/8] lockdep: Change IRQ state tracking to use per-cpu variables Peter Zijlstra
2020-06-23 8:36 ` [PATCH v4 1/8] lockdep: Prepare for NMI IRQ state tracking Peter Zijlstra
2020-06-23 8:36 ` [PATCH v4 2/8] x86/entry: Fix NMI vs " Peter Zijlstra
2020-06-23 8:36 ` [PATCH v4 3/8] sparc64: Fix asm/percpu.h build error Peter Zijlstra
2020-06-23 21:35 ` David Miller
2020-06-23 8:36 ` [PATCH v4 4/8] powerpc64: Break asm/percpu.h vs spinlock_types.h dependency Peter Zijlstra
2020-06-23 8:36 ` [PATCH v4 5/8] s390: Break cyclic percpu include Peter Zijlstra
2020-06-23 8:36 ` [PATCH v4 6/8] arm: " Peter Zijlstra
2020-06-23 9:02 ` Will Deacon
2020-06-24 17:53 ` Peter Zijlstra
2020-06-25 7:31 ` Will Deacon
2020-06-23 8:36 ` [PATCH v4 7/8] lockdep: Change hardirq{s_enabled, _context} to per-cpu variables Peter Zijlstra
2020-06-23 15:00 ` [PATCH v4 7/8] lockdep: Change hardirq{s_enabled,_context} " Ahmed S. Darwish
2020-06-23 15:24 ` Peter Zijlstra
2020-06-23 16:13 ` Ahmed S. Darwish
2020-06-23 16:37 ` Peter Zijlstra
2020-06-23 17:59 ` Marco Elver
2020-06-23 18:12 ` Peter Zijlstra
2020-06-23 18:39 ` Marco Elver
2020-06-23 19:13 ` Marco Elver
2020-06-23 19:41 ` Peter Zijlstra [this message]
2020-06-23 20:08 ` Peter Zijlstra
2020-06-23 20:24 ` Peter Zijlstra
2020-06-23 20:33 ` Peter Zijlstra
2020-06-24 9:00 ` Peter Zijlstra
2020-06-24 10:17 ` Marco Elver
2020-06-24 12:31 ` Peter Zijlstra
2020-06-24 11:32 ` Marco Elver
2020-06-24 15:18 ` Peter Zijlstra
2020-06-30 5:59 ` Ahmed S. Darwish
2020-06-30 9:40 ` Peter Zijlstra
2020-06-23 8:36 ` [PATCH v4 8/8] lockdep: Remove lockdep_hardirq{s_enabled, _context}() argument Peter Zijlstra
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