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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-mm <linux-mm@kvack.org>,
	"the arch/x86 maintainers" <x86@kernel.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Michal Hocko <mhocko@kernel.org>
Subject: Re: [mm 4.15-rc7] Random oopses under memory pressure.
Date: Mon, 15 Jan 2018 15:05:20 -0800	[thread overview]
Message-ID: <CA+55aFwvgm+KKkRLaFsuAjTdfQooS=UaMScC0CbZQ9WnX_AF=g@mail.gmail.com> (raw)
In-Reply-To: <201801142054.FAD95378.LVOOFQJOFtMFSH@I-love.SAKURA.ne.jp>

On Sun, Jan 14, 2018 at 3:54 AM, Tetsuo Handa
<penguin-kernel@i-love.sakura.ne.jp> wrote:
> This memory corruption bug occurs even on CONFIG_SMP=n CONFIG_PREEMPT_NONE=y
> kernel. This bug highly depends on timing and thus too difficult to bisect.
> This bug seems to exist at least since Linux 4.8 (judging from the traces, though
> the cause might be different). None of debugging configuration gives me a clue.
> So far only CONFIG_HIGHMEM=y CONFIG_DEBUG_PAGEALLOC=y kernel (with RAM enough to
> use HighMem: zone) seems to hit this bug, but it might be just by chance caused
> by timings. Thus, there is no evidence that 64bit kernels are not affected by
> this bug. But I can't narrow down any more. Thus, I call for developers who can
> narrow down / identify where the memory corruption bug is.

Hmm.

I guess I'm still hung up on the "it does not look like a valid
'struct page *'" thing.

Can you reproduce this with CONFIG_FLATMEM=y instead of CONFIG_SPARSEMEM?

Because if you can, I think we can easily add a few more pfn and
'struct page' validation debug statements. With SPARSEMEM, it gets
pretty complicated because the whole struct page setup is much more
complex.

              Linus

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  reply	other threads:[~2018-01-15 23:05 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <201801091939.JDJ64598.HOMFQtOFSOVLFJ@I-love.SAKURA.ne.jp>
     [not found] ` <201801102049.BGJ13564.OOOMtJLSFQFVHF@I-love.SAKURA.ne.jp>
     [not found]   ` <20180110124519.GU1732@dhcp22.suse.cz>
     [not found]     ` <201801102237.BED34322.QOOJMFFFHVLSOt@I-love.SAKURA.ne.jp>
     [not found]       ` <20180111135721.GC1732@dhcp22.suse.cz>
2018-01-11 14:11         ` [mm? " Tetsuo Handa
2018-01-11 14:21           ` Michal Hocko
2018-01-11 14:37             ` Tetsuo Handa
2018-01-12  1:31             ` [mm " Tetsuo Handa
2018-01-12  1:42               ` Linus Torvalds
2018-01-12 11:22                 ` Tetsuo Handa
2018-01-14 11:54                   ` Tetsuo Handa
2018-01-15 23:05                     ` Linus Torvalds [this message]
2018-01-16  1:15                       ` [mm 4.15-rc8] " Tetsuo Handa
2018-01-16  2:14                         ` Linus Torvalds
2018-01-16  8:06                           ` Dave Hansen
2018-01-16  8:37                             ` Ingo Molnar
2018-01-16 19:30                             ` Linus Torvalds
2018-01-16 17:33                           ` Tetsuo Handa
2018-01-16 19:34                             ` Linus Torvalds
2018-01-17 11:08                               ` Tetsuo Handa
2018-01-11 18:11           ` [mm? 4.15-rc7] " Linus Torvalds
2018-01-11 20:59             ` Tetsuo Handa

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