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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Hugh Dickins <hughd@google.com>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Wang Yugui <wangyugui@e16-tech.com>,
	Alistair Popple <apopple@nvidia.com>,
	Matthew Wilcox <willy@infradead.org>,
	Peter Xu <peterx@redhat.com>,
	Ralph Campbell <rcampbell@nvidia.com>,
	Will Deacon <will@kernel.org>, Yang Shi <shy828301@gmail.com>,
	Zi Yan <ziy@nvidia.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 18/25] mm/thp: another PVMW_SYNC fix in page_vma_mapped_walk()
Date: Fri,  9 Jul 2021 15:18:49 +0200	[thread overview]
Message-ID: <20210709131638.887630622@linuxfoundation.org> (raw)
In-Reply-To: <20210709131627.928131764@linuxfoundation.org>

From: Hugh Dickins <hughd@google.com>

[ Upstream commit a7a69d8ba88d8dcee7ef00e91d413a4bd003a814 ]

Aha! Shouldn't that quick scan over pte_none()s make sure that it holds
ptlock in the PVMW_SYNC case? That too might have been responsible for
BUGs or WARNs in split_huge_page_to_list() or its unmap_page(), though
I've never seen any.

Link: https://lkml.kernel.org/r/1bdf384c-8137-a149-2a1e-475a4791c3c@google.com
Link: https://lore.kernel.org/linux-mm/20210412180659.B9E3.409509F4@e16-tech.com/
Fixes: ace71a19cec5 ("mm: introduce page_vma_mapped_walk()")
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Wang Yugui <wangyugui@e16-tech.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 mm/page_vma_mapped.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index 16adeef76d00..a612daef5f00 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -271,6 +271,10 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
 				goto restart;
 			}
 			pvmw->pte++;
+			if ((pvmw->flags & PVMW_SYNC) && !pvmw->ptl) {
+				pvmw->ptl = pte_lockptr(mm, pvmw->pmd);
+				spin_lock(pvmw->ptl);
+			}
 		} while (pte_none(*pvmw->pte));
 
 		if (!pvmw->ptl) {
-- 
2.30.2




  parent reply	other threads:[~2021-07-09 13:19 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-09 13:18 [PATCH 4.14 00/25] 4.14.239-rc1 review Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 01/25] include/linux/mmdebug.h: make VM_WARN* non-rvals Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 02/25] mm: add VM_WARN_ON_ONCE_PAGE() macro Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 03/25] mm/rmap: remove unneeded semicolon in page_not_mapped() Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 04/25] mm/rmap: use page_not_mapped in try_to_unmap() Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 05/25] mm/thp: try_to_unmap() use TTU_SYNC for safe splitting Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 06/25] mm/thp: fix vma_address() if virtual address below file offset Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 07/25] mm/thp: fix page_address_in_vma() on file THP tails Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 08/25] mm: thp: replace DEBUG_VM BUG with VM_WARN when unmap fails for split Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 09/25] mm: page_vma_mapped_walk(): use page for pvmw->page Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 10/25] mm: page_vma_mapped_walk(): settle PageHuge on entry Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 11/25] mm: page_vma_mapped_walk(): use pmde for *pvmw->pmd Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 12/25] mm: page_vma_mapped_walk(): prettify PVMW_MIGRATION block Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 13/25] mm: page_vma_mapped_walk(): crossing page table boundary Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 14/25] mm: page_vma_mapped_walk(): add a level of indentation Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 15/25] mm: page_vma_mapped_walk(): use goto instead of while (1) Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 16/25] mm: page_vma_mapped_walk(): get vma_address_end() earlier Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 17/25] mm/thp: fix page_vma_mapped_walk() if THP mapped by ptes Greg Kroah-Hartman
2021-07-09 13:18 ` Greg Kroah-Hartman [this message]
2021-07-09 13:18 ` [PATCH 4.14 19/25] mm, futex: fix shared futex pgoff on shmem huge page Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 20/25] scsi: sr: Return appropriate error code when disk is ejected Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 21/25] drm/nouveau: fix dma_address check for CPU/GPU sync Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 22/25] kfifo: DECLARE_KIFO_PTR(fifo, u64) does not work on arm 32 bit Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 23/25] kthread_worker: split code for canceling the delayed work timer Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 24/25] kthread: prevent deadlock when kthread_mod_delayed_work() races with kthread_cancel_delayed_work_sync() Greg Kroah-Hartman
2021-07-09 13:18 ` [PATCH 4.14 25/25] xen/events: reset active flag for lateeoi events later Greg Kroah-Hartman
2021-07-10 14:05 ` [PATCH 4.14 00/25] 4.14.239-rc1 review Naresh Kamboju
2021-07-10 19:51 ` Guenter Roeck
2021-07-12  0:57 ` Samuel Zou

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