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From: "Petr Tesařík" <petr@tesarici.cz>
To: Richard Weinberger <richard@nod.at>
Cc: Petr Tesarik <petrtesarik@huaweicloud.com>,
	anton ivanov <anton.ivanov@cambridgegreys.com>,
	Johannes Berg <johannes@sipsolutions.net>,
	linux-um <linux-um@lists.infradead.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Roberto Sassu <roberto.sassu@huaweicloud.com>,
	Petr Tesarik <petr.tesarik1@huawei-partners.com>
Subject: Re: [PATCH 0/2] um: improve UML page fault handling
Date: Fri, 5 Jan 2024 07:51:09 +0100	[thread overview]
Message-ID: <20240105075109.4f0e2785@meshulam.tesarici.cz> (raw)
In-Reply-To: <435201914.200552.1704410531143.JavaMail.zimbra@nod.at>

Helo Richard,

Am Fri, 5 Jan 2024 00:22:11 +0100 (CET)
schrieb Richard Weinberger <richard@nod.at>:

> ----- Ursprüngliche Mail -----
> > Von: "Petr Tesarik" <petrtesarik@huaweicloud.com>
> > An: "richard" <richard@nod.at>, "anton ivanov" <anton.ivanov@cambridgegreys.com>, "Johannes Berg"
> > <johannes@sipsolutions.net>, "linux-um" <linux-um@lists.infradead.org>, "linux-kernel" <linux-kernel@vger.kernel.org>
> > CC: "Roberto Sassu" <roberto.sassu@huaweicloud.com>, petr@tesarici.cz, "Petr Tesarik"
> > <petr.tesarik1@huawei-partners.com>
> > Gesendet: Freitag, 15. Dezember 2023 13:14:29
> > Betreff: [PATCH 0/2] um: improve UML page fault handling  
> 
> > From: Petr Tesarik <petr.tesarik1@huawei-partners.com>
> > 
> > Improve UML handling of segmentation faults in kernel mode. Although
> > such page faults are generally caused by a kernel bug, it is annoying
> > if they cause an infinite loop, or panic the kernel. More importantly,
> > a robust implementation allows to write KUnit tests for various guard
> > pages, preventing potential kernel self-protection regressions.
> > 
> > Petr Tesarik (2):
> >  um: do not panic on kernel mode faults
> >  um: oops on accessing an non-present page in the vmalloc area  
> 
> I think this is a good thing to have.

Thanks for the feedback.

> For the implementation side, this needs to use the oops_* helpers
> from kernel/panic.c and taint the kernel, etc...

Yes, I did see that coming but wanted to get some confirmation that
it's worth the effort.

> See arch/x86/kernel/dumpstack.c die() and friends.

This implementation also calls die notifiers, but AFAICS different
architectures are not very consistent in their use. Do you also
require die notifiers for the UML implementation?

Petr T


  reply	other threads:[~2024-01-05  6:51 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-15 12:14 [PATCH 0/2] um: improve UML page fault handling Petr Tesarik
2023-12-15 12:14 ` [PATCH 1/2] um: do not panic on kernel mode faults Petr Tesarik
2023-12-15 12:14 ` [PATCH 2/2] um: oops on accessing an non-present page in the vmalloc area Petr Tesarik
2024-01-03 12:51 ` [PATCH 0/2] um: improve UML page fault handling Petr Tesařík
2024-01-04 23:22 ` Richard Weinberger
2024-01-05  6:51   ` Petr Tesařík [this message]
2024-01-26  9:55     ` Petr Tesařík

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