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From: Matthew Wilcox <willy@linux.intel.com>
To: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Andres Lagar-Cavilla <andreslc@google.com>,
	Yang Shi <yang.shi@linaro.org>, Ning Qu <quning@gmail.com>,
	David Rientjes <rientjes@google.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 09/10] huge pagecache: mmap_sem is unlocked when truncation splits pmd
Date: Thu, 14 Apr 2016 13:39:22 -0400	[thread overview]
Message-ID: <20160414173922.GE3120@linux.intel.com> (raw)
In-Reply-To: <alpine.LSU.2.11.1604051352540.5965@eggly.anvils>

On Tue, Apr 05, 2016 at 01:55:23PM -0700, Hugh Dickins wrote:
> zap_pmd_range()'s CONFIG_DEBUG_VM !rwsem_is_locked(&mmap_sem) BUG()
> will be invalid with huge pagecache, in whatever way it is implemented:
> truncation of a hugely-mapped file to an unhugely-aligned size would
> easily hit it.

We can reproduce this BUG() in the current Linus tree with DAX PMDs.
Andrew, can you send this patch to Linus for inclusion in 4.7?

Tested-by: Matthew Wilcox <willy@linux.intel.com>

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  parent reply	other threads:[~2016-04-14 17:39 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-05 20:37 [PATCH 00/10] mm: easy preliminaries to THPagecache Hugh Dickins
2016-04-05 20:40 ` [PATCH 01/10] mm: update_lru_size warn and reset bad lru_size Hugh Dickins
2016-04-14 11:56   ` Vlastimil Babka
2016-04-05 20:42 ` [PATCH 02/10] mm: update_lru_size do the __mod_zone_page_state Hugh Dickins
2016-04-05 20:44 ` [PATCH 03/10] mm: use __SetPageSwapBacked and dont ClearPageSwapBacked Hugh Dickins
2016-04-06  9:52   ` Mel Gorman
2016-04-05 20:45 ` [PATCH 04/10] tmpfs: preliminary minor tidyups Hugh Dickins
2016-04-05 20:47 ` [PATCH 05/10] tmpfs: mem_cgroup charge fault to vm_mm not current mm Hugh Dickins
2016-04-05 20:49 ` [PATCH 06/10] mm: /proc/sys/vm/stat_refresh to force vmstat update Hugh Dickins
2016-04-05 20:51 ` [PATCH 07/10] huge mm: move_huge_pmd does not need new_vma Hugh Dickins
2016-04-11 10:28   ` Kirill A. Shutemov
2016-04-05 20:52 ` [PATCH 08/10] huge pagecache: extend mremap pmd rmap lockout to files Hugh Dickins
2016-04-11 10:32   ` Kirill A. Shutemov
2016-04-05 20:55 ` [PATCH 09/10] huge pagecache: mmap_sem is unlocked when truncation splits pmd Hugh Dickins
2016-04-11 10:35   ` Kirill A. Shutemov
2016-04-14 17:39   ` Matthew Wilcox [this message]
2016-04-16  4:55     ` Andrew Morton
2016-04-05 21:02 ` [PATCH 10/10] arch: fix has_transparent_hugepage() Hugh Dickins
2016-04-05 23:25   ` David Miller
2016-04-06  3:22   ` Vineet Gupta
2016-04-06  6:58   ` Ingo Molnar
2016-04-06 12:29     ` Chris Metcalf
2016-04-06 21:58       ` Ingo Molnar
2016-04-06 11:56   ` Gerald Schaefer

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