From: Will Deacon <will.deacon@arm.com>
To: Qian Cai <cai@lca.pw>
Cc: Andrey Konovalov <andreyknvl@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
kasan-dev <kasan-dev@googlegroups.com>,
aryabinin@virtuozzo.com
Subject: Re: livelock with KASAN_SW_TAGS
Date: Thu, 14 Feb 2019 16:35:36 +0000 [thread overview]
Message-ID: <20190214163536.GB1825@fuggles.cambridge.arm.com> (raw)
In-Reply-To: <7ec14ad5-8d64-b842-a819-9d57cc8495e2@lca.pw>
Hi Qian Cai,
On Wed, Feb 13, 2019 at 10:32:11PM -0500, Qian Cai wrote:
> Running LTP msgstress03 [1] triggers endless soft lockups below after a few
> minutes on a ThunderX2 server. It works fine with KASAN_GENERIC and finish the
> test in roughly 11 minutes.
I've not been able to reproduce this failure under KVM, however the test
only takes around 18s to complete on the host and the guest, so it feels
like something is amiss here. Please could you share more information about
how you're triggering this problem? For example:
- Kernel version and .config
- Clang version
- LTP version and command-line
- Machine configuration (CPUs, memory, etc)
> # ./scripts/faddr2line vmlinux _raw_spin_unlock_irqrestore+0x44/0xac
> _raw_spin_unlock_irqrestore+0x44/0xac:
> arch_local_irq_restore at arch/arm64/include/asm/irqflags.h:88
> (inlined by) __raw_spin_unlock_irqrestore at include/linux/spinlock_api_smp.h:160
> (inlined by) _raw_spin_unlock_irqrestore at kernel/locking/spinlock.c:184
>
> This code:
>
> asm volatile(
> "msr daif, %0
> :
> : "r" (flags)
> : "memory");
This is just the instruction when we unmask interrupts, so that's when the
soft watchdog fires. I suspect the real issue is that we're spending lots
of time in:
> [ 545.772027] free_debug_processing+0x308/0x410
with irqs disabled. Does the machine eventually come back to life?
Will
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next prev parent reply other threads:[~2019-02-14 16:35 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-14 3:32 livelock with KASAN_SW_TAGS Qian Cai
2019-02-14 16:35 ` Will Deacon [this message]
2019-02-14 16:50 ` Qian Cai
2019-02-14 18:01 ` Will Deacon
2019-02-15 4:04 ` Qian Cai
2019-02-15 14:23 ` Will Deacon
2019-02-15 14:26 ` Will Deacon
2019-02-19 17:56 ` Andrey Konovalov
[not found] ` <1550601754.6911.41.camel@lca.pw>
2019-02-19 18:56 ` soft lockups with SLAB_CONSISTENCY_CHECKS + KASAN_SW_TAGS (was: livelock with KASAN_SW_TAGS) Andrey Konovalov
2019-02-19 19:08 ` Qian Cai
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