From: Yang Shi <shy828301@gmail.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Hugh Dickins <hughd@google.com>, Song Liu <song@kernel.org>,
Rongwei Wang <rongwei.wang@linux.alibaba.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linux MM <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
William Kucharski <william.kucharski@oracle.com>
Subject: Re: [PATCH v2 1/2] mm, thp: check page mapping when truncating page cache
Date: Mon, 4 Oct 2021 11:28:45 -0700 [thread overview]
Message-ID: <CAHbLzkosZr_ugNAMbXreUumSyAUMH1hPhTaiXXXRUNx88J9Xsw@mail.gmail.com> (raw)
In-Reply-To: <YViSGYhn+zTShwFP@casper.infradead.org>
On Sat, Oct 2, 2021 at 10:09 AM Matthew Wilcox <willy@infradead.org> wrote:
>
> On Thu, Sep 30, 2021 at 10:39:14AM -0700, Yang Shi wrote:
> > On Thu, Sep 30, 2021 at 9:49 AM Hugh Dickins <hughd@google.com> wrote:
> > > I assume you're thinking of one of the fuzzer blkdev ones:
> > > https://lore.kernel.org/linux-mm/CACkBjsbtF_peC7N_4mRfHML_BeiPe+O9DahTfr84puSG_J9rcQ@mail.gmail.com/
> > > or
> > > https://lore.kernel.org/lkml/CACkBjsYwLYLRmX8GpsDpMthagWOjWWrNxqY6ZLNQVr6yx+f5vA@mail.gmail.com/
> > >
> > > I haven't started on those ones yet: yes, I imagine one or both of those
> > > will need a further fix (S_ISREG() check somewhere if we're lucky; but
> > > could well be nastier); but for the bug in this thread, I expect
> >
> > Makes sense to me. We should be able to check S_ISREG() in khugepaged,
> > if it is not a regular file, just bail out. Sounds not that nasty to
> > me AFAIU.
>
> I don't see why we should have an S_ISREG() check. I agree it's not the
> intended usecase, but it ought to work fine. Unless there's something
> I'm missing?
Check out this bug report:
https://lore.kernel.org/lkml/CACkBjsYwLYLRmX8GpsDpMthagWOjWWrNxqY6ZLNQVr6yx+f5vA@mail.gmail.com/
and the patch from me:
https://lore.kernel.org/linux-mm/20210917205731.262693-1-shy828301@gmail.com/
I don't think we handle buffers correctly for file THP, right? My
patch is ad hoc, so I thought Hugh's suggestion makes some sense to
me. Why do we have THP collapsed for unintended usecase in the first
place?
next prev parent reply other threads:[~2021-10-04 18:29 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-06 12:11 [PATCH 0/2] mm, thp: fix file-backed THP race in collapse_file Rongwei Wang
2021-09-06 12:11 ` [PATCH 1/2] mm, thp: check page mapping when truncating page cache Rongwei Wang
2021-09-07 2:49 ` Yu Xu
2021-09-07 18:08 ` Yang Shi
2021-09-08 2:35 ` Rongwei Wang
2021-09-08 21:48 ` Yang Shi
2021-09-09 1:25 ` Rongwei Wang
2021-09-13 14:49 ` [mm, thp] 20753096b6: BUG:unable_to_handle_page_fault_for_address kernel test robot
2021-09-06 12:12 ` [PATCH 2/2] mm, thp: bail out early in collapse_file for writeback page Rongwei Wang
2021-09-07 16:56 ` Yang Shi
2021-09-08 2:16 ` Rongwei Wang
2021-09-08 21:51 ` Yang Shi
2021-09-09 1:33 ` Rongwei Wang
2021-09-22 7:06 ` [PATCH v2 0/2] mm, thp: fix file-backed THP race in collapse_file and truncate pagecache Rongwei Wang
2021-09-22 7:06 ` [PATCH v2 1/2] mm, thp: check page mapping when truncating page cache Rongwei Wang
2021-09-22 11:37 ` Matthew Wilcox
2021-09-22 17:04 ` Rongwei Wang
2021-09-24 2:43 ` Andrew Morton
2021-09-24 3:08 ` Yang Shi
2021-09-24 3:35 ` Rongwei Wang
2021-09-24 7:12 ` Rongwei Wang
2021-09-27 22:24 ` Song Liu
2021-09-28 12:06 ` Matthew Wilcox
2021-09-28 16:59 ` Song Liu
2021-09-28 16:20 ` Rongwei Wang
2021-09-29 7:14 ` Song Liu
2021-09-29 7:50 ` Rongwei Wang
2021-09-29 16:59 ` Song Liu
2021-09-29 17:55 ` Matthew Wilcox
2021-09-29 23:41 ` Song Liu
2021-09-30 0:00 ` Matthew Wilcox
2021-09-30 0:41 ` Song Liu
2021-09-30 2:14 ` Rongwei Wang
2021-10-04 17:26 ` Rongwei Wang
2021-10-04 19:05 ` Matthew Wilcox
2021-10-05 1:58 ` Rongwei Wang
2021-10-04 20:26 ` Song Liu
2021-10-05 2:58 ` Hugh Dickins
2021-10-05 3:07 ` Matthew Wilcox
2021-10-05 9:03 ` Rongwei Wang
2021-09-30 1:54 ` Rongwei Wang
2021-09-30 3:26 ` Song Liu
2021-09-30 5:24 ` Hugh Dickins
2021-09-30 15:28 ` Matthew Wilcox
2021-09-30 16:49 ` Hugh Dickins
2021-09-30 17:39 ` Yang Shi
2021-10-02 17:08 ` Matthew Wilcox
2021-10-04 18:28 ` Yang Shi [this message]
2021-10-04 19:31 ` Matthew Wilcox
2021-10-05 2:26 ` Hugh Dickins
2021-10-02 2:22 ` Rongwei Wang
2021-09-22 7:06 ` [PATCH v2 2/2] mm, thp: bail out early in collapse_file for writeback page Rongwei Wang
2021-10-06 2:18 ` [PATCH v3 v3 0/2] mm, thp: fix file-backed THP race in collapse_file and truncate pagecache Rongwei Wang
2021-10-06 2:18 ` [PATCH v3 v3 1/2] mm, thp: lock filemap when truncating page cache Rongwei Wang
2021-10-06 2:18 ` [PATCH v3 v3 2/2] mm, thp: bail out early in collapse_file for writeback page Rongwei Wang
2021-10-06 2:41 ` Matthew Wilcox
2021-10-06 8:39 ` Rongwei Wang
2021-10-06 17:58 ` Yang Shi
2021-10-11 2:22 ` [PATCH v4 0/2] mm, thp: fix file-backed THP race in collapse_file and truncate pagecache Rongwei Wang
2021-10-11 2:22 ` [PATCH v4 1/2] mm, thp: lock filemap when truncating page cache Rongwei Wang
2021-10-13 7:55 ` Rongwei Wang
2021-10-11 2:22 ` [PATCH v4 2/2] mm, thp: bail out early in collapse_file for writeback page Rongwei Wang
2021-10-11 3:08 ` Matthew Wilcox
2021-10-11 3:22 ` Rongwei Wang
2021-10-11 5:08 ` [PATCH v4 RESEND " Rongwei Wang
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