From: Hugh Dickins <hughd@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>,
Matthew Wilcox <willy@infradead.org>,
William Kucharski <william.kucharski@oracle.com>,
Christoph Hellwig <hch@lst.de>, Jan Kara <jack@suse.cz>,
Dave Chinner <dchinner@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Yang Shi <yang.shi@linux.alibaba.com>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org
Subject: [PATCH 1/2] mm/filemap: fix find_lock_entries hang on 32-bit THP
Date: Wed, 21 Apr 2021 17:37:33 -0700 (PDT) [thread overview]
Message-ID: <alpine.LSU.2.11.2104211735430.3299@eggly.anvils> (raw)
In-Reply-To: <alpine.LSU.2.11.2104211723580.3299@eggly.anvils>
No problem on 64-bit, or without huge pages, but xfstests generic/308
hung uninterruptibly on 32-bit huge tmpfs. Since 4.13's 0cc3b0ec23ce
("Clarify (and fix) MAX_LFS_FILESIZE macros"), MAX_LFS_FILESIZE is
only a PAGE_SIZE away from wrapping 32-bit xa_index to 0, so the new
find_lock_entries() has to be extra careful when handling a THP.
Fixes: 5c211ba29deb ("mm: add and use find_lock_entries")
Signed-off-by: Hugh Dickins <hughd@google.com>
---
mm/filemap.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
--- 5.12-rc8/mm/filemap.c 2021-02-26 19:42:39.812156085 -0800
+++ linux/mm/filemap.c 2021-04-20 23:20:20.509464440 -0700
@@ -1969,8 +1969,14 @@ unlock:
put:
put_page(page);
next:
- if (!xa_is_value(page) && PageTransHuge(page))
- xas_set(&xas, page->index + thp_nr_pages(page));
+ if (!xa_is_value(page) && PageTransHuge(page)) {
+ unsigned int nr_pages = thp_nr_pages(page);
+
+ /* Final THP may cross MAX_LFS_FILESIZE on 32-bit */
+ xas_set(&xas, page->index + nr_pages);
+ if (xas.xa_index < nr_pages)
+ break;
+ }
}
rcu_read_unlock();
next prev parent reply other threads:[~2021-04-22 0:37 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-22 0:35 [PATCH 0/2] mm/filemap: fix 5.12-rc regressions Hugh Dickins
2021-04-22 0:37 ` Hugh Dickins [this message]
2021-04-22 1:06 ` [PATCH 1/2] mm/filemap: fix find_lock_entries hang on 32-bit THP Matthew Wilcox
2021-04-22 0:39 ` [PATCH 2/2] mm/filemap: fix mapping_seek_hole_data on THP & 32-bit Hugh Dickins
2021-04-22 1:16 ` Matthew Wilcox
2021-04-22 5:55 ` Hugh Dickins
2021-04-22 20:46 ` Hugh Dickins
2021-04-22 20:48 ` [PATCH v2 " Hugh Dickins
2021-04-22 23:04 ` Andrew Morton
2021-04-23 17:22 ` Hugh Dickins
2021-04-23 19:29 ` Andrew Morton
2021-04-23 20:08 ` Hugh Dickins
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