From: "Huang\, Ying" <ying.huang@intel.com>
To: Qian Cai <cai@lca.pw>
Cc: Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Minchan Kim <minchan@kernel.org>,
Hugh Dickins <hughd@google.com>,
"Andrew Morton" <akpm@linux-foundation.org>
Subject: Re: linux-next: not-present page at swap_vma_readahead()
Date: Wed, 15 Apr 2020 10:01:53 +0800 [thread overview]
Message-ID: <874ktl1p7y.fsf@yhuang-dev.intel.com> (raw)
In-Reply-To: <81F06AA9-F25B-4342-9CF7-2763AC394A18@lca.pw> (Qian Cai's message of "Tue, 14 Apr 2020 17:22:54 -0400")
Qian Cai <cai@lca.pw> writes:
>> On Apr 14, 2020, at 10:32 AM, Qian Cai <cai@lca.pw> wrote:
>>
>> Fuzzers are unhappy. Thoughts?
>
> This is rather to reproduce. All the traces so far are from copy_from_user() to trigger a page fault,
> and then it dereferences a bad pte in swap_vma_readahead(),
>
> for (i = 0, pte = ra_info.ptes; i < ra_info.nr_pte;
> i++, pte++) {
> pentry = *pte; <— crashed here.
> if (pte_none(pentry))
Is it possible to bisect this?
Because the crash point is identified, it may be helpful to collect and
analyze the status of the faulting page table and readahead ptes. But I
am not familiar with the ARM64 architecture. So I cannot help much
here.
Best Regards,
Huang, Ying
next prev parent reply other threads:[~2020-04-15 2:02 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-14 14:32 linux-next: not-present page at swap_vma_readahead() Qian Cai
2020-04-14 21:22 ` Qian Cai
2020-04-15 2:01 ` Huang, Ying [this message]
2020-04-15 2:12 ` Qian Cai
2020-04-15 8:54 ` Huang, Ying
2020-04-15 13:11 ` Qian Cai
[not found] ` <20200616011334.GA815@lca.pw>
2020-07-20 0:37 ` Huang, Ying
2020-07-20 2:12 ` Qian Cai
2020-07-20 3:32 ` Huang, Ying
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