From: Linus Torvalds <torvalds@linux-foundation.org>
To: Joel Fernandes <joel@joelfernandes.org>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>,
linux- stable <stable@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>, Arnd Bergmann <arnd@arndb.de>,
Andrew Morton <akpm@linux-foundation.org>,
Roman Gushchin <guro@fb.com>, Michal Hocko <mhocko@kernel.org>,
lkft-triage@lists.linaro.org, Chris Down <chris@chrisdown.name>,
Michel Lespinasse <walken@google.com>,
Fan Yang <Fan_Yang@sjtu.edu.cn>,
Brian Geffon <bgeffon@google.com>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Will Deacon <will@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
pugaowei@gmail.com, Jerome Glisse <jglisse@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Mel Gorman <mgorman@techsingularity.net>,
Hugh Dickins <hughd@google.com>,
Al Viro <viro@zeniv.linux.org.uk>, Tejun Heo <tj@kernel.org>,
Sasha Levin <sashal@kernel.org>
Subject: Re: WARNING: at mm/mremap.c:211 move_page_tables in i386
Date: Sun, 12 Jul 2020 20:51:26 -0700 [thread overview]
Message-ID: <CAHk-=whmbpZN6-Q=8cDM42UmHmqzgNDucLLP4BvR1jQ73+KSgw@mail.gmail.com> (raw)
In-Reply-To: <20200713025354.GB3644504@google.com>
On Sun, Jul 12, 2020 at 7:53 PM Joel Fernandes <joel@joelfernandes.org> wrote:
>
> > But I do feel like you figured out why the bug happened, now we're
> > just discussing whether the patch is the right thing to do.
>
> Yes.
>
> > Maybe saying "doing the pmd copies for the initial stack isn't
> > important, so let's just note this as a special case and get rid of
> > the WARN_ON()" might be an alternative solution.
>
> Personally, I feel it is better to keep the warning just so in the future we
> can detect any bugs.
I don't disagree, the warning didn't happen to find a bug now, but it
did fine a case we might be able to do better.
So now that I feel we understand the issue, and it's not a horrible
problem, just a (very hard to trigger) warning, I don't think there's
any huge hurry.
I think think I will - for now - change the WARN_ON() to
WARN_ON_ONCE() (so that it doesn't floow the logs if somebody triggers
this odd special case this malisiously), and add a note about how
this happens to the code for posterito.
And if/when you figure out a better way to fix it, we can update the note.
Ok?
Linus
next prev parent reply other threads:[~2020-07-13 3:53 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-09 5:28 WARNING: at mm/mremap.c:211 move_page_tables in i386 Naresh Kamboju
2020-07-09 8:25 ` Arnd Bergmann
2020-07-10 4:17 ` Naresh Kamboju
2020-07-09 19:12 ` Linus Torvalds
2020-07-10 4:28 ` Naresh Kamboju
2020-07-10 5:22 ` Linus Torvalds
2020-07-10 17:48 ` Naresh Kamboju
2020-07-10 20:05 ` Linus Torvalds
2020-07-11 17:27 ` Naresh Kamboju
2020-07-11 18:12 ` Linus Torvalds
2020-07-11 18:21 ` Linus Torvalds
2020-07-11 23:33 ` Joel Fernandes
2020-07-12 17:30 ` Matthew Wilcox
2020-07-12 20:38 ` Linus Torvalds
2020-07-12 21:50 ` Joel Fernandes
2020-07-12 22:58 ` Linus Torvalds
2020-07-13 2:53 ` Joel Fernandes
2020-07-13 3:51 ` Linus Torvalds [this message]
2020-07-13 12:12 ` Joel Fernandes
2020-07-14 7:33 ` Kirill A. Shutemov
2020-07-14 11:27 ` Naresh Kamboju
2020-07-14 16:08 ` Joel Fernandes
2020-07-14 16:10 ` Linus Torvalds
2020-07-14 18:12 ` Joel Fernandes
2020-07-14 18:49 ` Linus Torvalds
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