From: Pasha Tatashin <pasha.tatashin@soleen.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Jonathan Corbet <corbet@lwn.net>, linux-mm <linux-mm@kvack.org>,
Linux Doc Mailing List <linux-doc@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Rick Edgecombe <rick.p.edgecombe@intel.com>
Subject: Re: [PATCH 2/3] mm/page_table_check: Do WARN_ON instead of BUG_ON by default
Date: Sun, 11 Sep 2022 16:42:34 -0400 [thread overview]
Message-ID: <CA+CK2bD5ae0oUefiGMAzxun4-rJhqUdfJqbzcCkZM_Uek-KTxQ@mail.gmail.com> (raw)
In-Reply-To: <Yx4IEvkmAlcTIP6v@casper.infradead.org>
On Sun, Sep 11, 2022 at 12:08 PM Matthew Wilcox <willy@infradead.org> wrote:
>
> On Sun, Sep 11, 2022 at 09:59:22AM +0000, Pasha Tatashin wrote:
> > Currently, page_table_check when detects errors panics kernel. Instead,
> > print a warning, and panic only when specifically requested via kernel
> > parameter:
> >
> > page_table_check=panic
>
> Why are the page table checks so special that they deserve their own
> command line parameter? Why shouldn't this be controlled by the usual
> panic_on_warn option?
page_table_check can be used as a security feature preventing false
page sharing between address spaces. For example, at Google we want it
to keep enabled on production systems, yet we do not want to enable
panic_on_warn as it would cause panics for many other reasons which
are security unrelated.
Pasha
next prev parent reply other threads:[~2022-09-11 20:43 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-11 9:59 [PATCH 0/3] page table check default to warn instead of panic Pasha Tatashin
2022-09-11 9:59 ` [PATCH 1/3] mm/page_table_check: Check writable zero page in page table check Pasha Tatashin
2022-09-12 15:58 ` Edgecombe, Rick P
2022-09-26 8:26 ` David Hildenbrand
2022-09-11 9:59 ` [PATCH 2/3] mm/page_table_check: Do WARN_ON instead of BUG_ON by default Pasha Tatashin
2022-09-11 16:08 ` Matthew Wilcox
2022-09-11 20:42 ` Pasha Tatashin [this message]
2022-09-26 8:28 ` David Hildenbrand
2022-09-26 1:16 ` [mm/page_table_check] 6e807506f4: WARNING:at_mm/page_table_check.c:#page_table_check_set kernel test robot
2022-09-26 1:16 ` kernel test robot
2022-09-11 9:59 ` [PATCH 3/3] doc/vm: add information about page_table_check=panic Pasha Tatashin
2022-09-12 20:23 ` [PATCH 0/3] page table check default to warn instead of panic Andrew Morton
2022-09-20 18:11 ` Pasha Tatashin
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