From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Joel Fernandes <joel@joelfernandes.org>,
Naresh Kamboju <naresh.kamboju@linaro.org>,
linux- stable <stable@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>, Arnd Bergmann <arnd@arndb.de>,
Andrew Morton <akpm@linux-foundation.org>,
Roman Gushchin <guro@fb.com>, Michal Hocko <mhocko@kernel.org>,
lkft-triage@lists.linaro.org, Chris Down <chris@chrisdown.name>,
Michel Lespinasse <walken@google.com>,
Fan Yang <Fan_Yang@sjtu.edu.cn>,
Brian Geffon <bgeffon@google.com>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Will Deacon <will@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
pugaowei@gmail.com, Jerome Glisse <jglisse@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Mel Gorman <mgorman@techsingularity.net>,
Hugh Dickins <hughd@google.com>,
Al Viro <viro@zeniv.linux.org.uk>, Tejun Heo <tj@kernel.org>,
Sasha Levin <sashal@kernel.org>
Subject: Re: WARNING: at mm/mremap.c:211 move_page_tables in i386
Date: Tue, 14 Jul 2020 10:33:06 +0300 [thread overview]
Message-ID: <20200714073306.kq4zikkphqje2yzb@box> (raw)
In-Reply-To: <CAHk-=whxP0Gj70pJN5R7Qec4qjrGr+G9Ex7FJi7=_fPcdQ2ocQ@mail.gmail.com>
On Sun, Jul 12, 2020 at 03:58:06PM -0700, Linus Torvalds wrote:
> Anybody else have any opinions?
Maybe we just shouldn't allow move_normal_pmd() if ranges overlap?
Other option: pass 'overlaps' down to move_normal_pmd() and only WARN() if
see establised PMD without overlaps being true.
Untested patch:
diff --git a/mm/mremap.c b/mm/mremap.c
index 5dd572d57ca9..e33fcee541fe 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -245,6 +245,18 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
unsigned long extent, next, old_end;
struct mmu_notifier_range range;
pmd_t *old_pmd, *new_pmd;
+ bool overlaps;
+
+ /*
+ * shift_arg_pages() can call move_page_tables() on overlapping ranges.
+ * In this case we cannot use move_normal_pmd() because destination pmd
+ * might be established page table: move_ptes() doesn't free page
+ * table.
+ */
+ if (old_addr > new_addr)
+ overlaps = old_addr - new_addr < len;
+ else
+ overlaps = new_addr - old_addr < len;
old_end = old_addr + len;
flush_cache_range(vma, old_addr, old_end);
@@ -282,7 +294,7 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
split_huge_pmd(vma, old_pmd, old_addr);
if (pmd_trans_unstable(old_pmd))
continue;
- } else if (extent == PMD_SIZE) {
+ } else if (!overlaps && extent == PMD_SIZE) {
#ifdef CONFIG_HAVE_MOVE_PMD
/*
* If the extent is PMD-sized, try to speed the move by
--
Kirill A. Shutemov
next prev parent reply other threads:[~2020-07-14 7:33 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-09 5:28 WARNING: at mm/mremap.c:211 move_page_tables in i386 Naresh Kamboju
2020-07-09 8:25 ` Arnd Bergmann
2020-07-10 4:17 ` Naresh Kamboju
2020-07-09 19:12 ` Linus Torvalds
2020-07-10 4:28 ` Naresh Kamboju
2020-07-10 5:22 ` Linus Torvalds
2020-07-10 17:48 ` Naresh Kamboju
2020-07-10 20:05 ` Linus Torvalds
2020-07-11 17:27 ` Naresh Kamboju
2020-07-11 18:12 ` Linus Torvalds
2020-07-11 18:21 ` Linus Torvalds
2020-07-11 23:33 ` Joel Fernandes
2020-07-12 17:30 ` Matthew Wilcox
2020-07-12 20:38 ` Linus Torvalds
2020-07-12 21:50 ` Joel Fernandes
2020-07-12 22:58 ` Linus Torvalds
2020-07-13 2:53 ` Joel Fernandes
2020-07-13 3:51 ` Linus Torvalds
2020-07-13 12:12 ` Joel Fernandes
2020-07-14 7:33 ` Kirill A. Shutemov [this message]
2020-07-14 11:27 ` Naresh Kamboju
2020-07-14 16:08 ` Joel Fernandes
2020-07-14 16:10 ` Linus Torvalds
2020-07-14 18:12 ` Joel Fernandes
2020-07-14 18:49 ` Linus Torvalds
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