From: Pavel Tatashin <pasha.tatashin@soleen.com>
To: Mark Rutland <mark.rutland@arm.com>
Cc: James Morris <jmorris@namei.org>, Sasha Levin <sashal@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
steve.capper@arm.com,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Marc Zyngier <marc.zyngier@arm.com>,
James Morse <james.morse@arm.com>,
Vladimir Murzin <vladimir.murzin@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
allison@lohutok.net, info@metux.net, alexios.zavras@intel.com
Subject: Re: [PATCH] arm64: kernel: memory corruptions due non-disabled PAN
Date: Wed, 20 Nov 2019 14:52:06 -0500 [thread overview]
Message-ID: <CA+CK2bDvp=RR7A5J097W3tr2QG_cOZgDMno388EXGAYW6+Q1Mg@mail.gmail.com> (raw)
In-Reply-To: <CA+CK2bCX+QGMPzhjj-UmVNb1jG8Z6WNW=L0GiVsTpGrhyqb9tA@mail.gmail.com>
On Wed, Nov 20, 2019 at 2:46 PM Pavel Tatashin
<pasha.tatashin@soleen.com> wrote:
>
> > > I see that with CONFIG_ARM64_SW_TTBR0_PAN=y, this means that we may
> > > leave the stale TTBR0 value installed across a context-switch (and have
> > > reproduced that locally), but I'm having some difficulty reproducing the
> > > corruption that you see.
> >
> > I will send the full test shortly. Note, I was never able to reproduce
> > it in QEMU, only on real hardware. Also, for some unknown reason after
> > kexec I could not reproduce it only during first boot, so it is
> > somewhat fragile, but I am sure it can be reproduced in other cases as
> > well, it is just my reproducer is not tunes for that.
> >
>
> Attached is the test program that I used to reproduce memory corruption.
> Test on board with Broadcom's Stingray SoC.
I forgot to remove from repro.c some of the stuff that I used for debugging:
get_pa() and sched_setaffinity() stuff are not needed.
>
> Without fix:
> # time /tmp/repro
> Corruption: pid 1474 map[0] 1488 cpu 3
> Terminated
>
> real 0m0.088s
> user 0m0.004s
> sys 0m0.071s
>
> With the fix:
>
> # time /tmp/repro
> Test passed, all good
> Terminated
>
> real 1m1.286s
> user 0m0.004s
> sys 0m0.970s
>
>
>
> Pasha
next prev parent reply other threads:[~2019-11-20 19:52 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-19 22:10 [PATCH] arm64: kernel: memory corruptions due non-disabled PAN Pavel Tatashin
2019-11-20 16:43 ` Mark Rutland
2019-11-20 16:55 ` Pavel Tatashin
2019-11-20 19:46 ` Pavel Tatashin
2019-11-20 19:52 ` Pavel Tatashin [this message]
2019-11-20 19:16 ` Will Deacon
2019-11-20 19:46 ` Pavel Tatashin
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