From: Mike Kravetz <mike.kravetz@oracle.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: Roman Gushchin <guro@fb.com>, Michal Hocko <mhocko@suse.com>,
Shakeel Butt <shakeelb@google.com>,
Oscar Salvador <osalvador@suse.de>,
David Hildenbrand <david@redhat.com>,
Muchun Song <songmuchun@bytedance.com>,
David Rientjes <rientjes@google.com>,
Miaohe Lin <linmiaohe@huawei.com>,
Peter Zijlstra <peterz@infradead.org>,
Matthew Wilcox <willy@infradead.org>,
HORIGUCHI NAOYA <naoya.horiguchi@nec.com>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
Waiman Long <longman@redhat.com>, Peter Xu <peterx@redhat.com>,
Mina Almasry <almasrymina@google.com>,
Hillf Danton <hdanton@sina.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Barry Song <song.bao.hua@hisilicon.com>,
Will Deacon <will@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Mike Kravetz <mike.kravetz@oracle.com>
Subject: [PATCH v2 0/8] make hugetlb put_page safe for all calling contexts
Date: Mon, 29 Mar 2021 16:23:54 -0700 [thread overview]
Message-ID: <20210329232402.575396-1-mike.kravetz@oracle.com> (raw)
This effort is the result a recent bug report [1]. Syzbot found a
potential deadlock in the hugetlb put_page/free_huge_page_path.
WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
Since the free_huge_page_path already has code to 'hand off' page
free requests to a workqueue, a suggestion was proposed to make
the in_irq() detection accurate by always enabling PREEMPT_COUNT [2].
The outcome of that discussion was that the hugetlb put_page path
(free_huge_page) path should be properly fixed and safe for all calling
contexts.
This series is based on v5.12-rc3-mmotm-2021-03-17-22-24. At a high
level, the series provides:
- Patches 1 & 2 change CMA bitmap mutex to an irq safe spinlock
- Patch 3 adds a mutex for proc/sysfs interfaces changing hugetlb counts
- Patches 4, 5 & 6 are aimed at reducing lock hold times. To be clear
the goal is to eliminate single lock hold times of a long duration.
Overall lock hold time is not addressed.
- Patch 7 makes hugetlb_lock and subpool lock IRQ safe. It also reverts
the code which defers calls to a workqueue if !in_task.
- Patch 8 adds some lockdep_assert_held() calls
[1] https://lore.kernel.org/linux-mm/000000000000f1c03b05bc43aadc@google.com/
[2] http://lkml.kernel.org/r/20210311021321.127500-1-mike.kravetz@oracle.com
v1 -> v2
- Drop Roman's cma_release_nowait() patches and just change CMA mutex
to an IRQ safe spinlock.
- Cleanups to variable names, commets and commit messages as suggested
by Michal, Oscar, Miaohe and Muchun.
- Dropped unnecessary INIT_LIST_HEAD as suggested by Michal and list_del
as suggested by Muchun.
- Created update_and_free_pages_bulk helper as suggested by Michal.
- Rebased on v5.12-rc4-mmotm-2021-03-28-16-37
- Added Acked-by: and Reviewed-by: from v1
RFC -> v1
- Add Roman's cma_release_nowait() patches. This eliminated the need
to do a workqueue handoff in hugetlb code.
- Use Michal's suggestion to batch pages for freeing. This eliminated
the need to recalculate loop control variables when dropping the lock.
- Added lockdep_assert_held() calls
- Rebased to v5.12-rc3-mmotm-2021-03-17-22-24
Mike Kravetz (8):
mm/cma: change cma mutex to irq safe spinlock
hugetlb: no need to drop hugetlb_lock to call cma_release
hugetlb: add per-hstate mutex to synchronize user adjustments
hugetlb: create remove_hugetlb_page() to separate functionality
hugetlb: call update_and_free_page without hugetlb_lock
hugetlb: change free_pool_huge_page to remove_pool_huge_page
hugetlb: make free_huge_page irq safe
hugetlb: add lockdep_assert_held() calls for hugetlb_lock
include/linux/hugetlb.h | 1 +
mm/cma.c | 20 +--
mm/cma.h | 2 +-
mm/cma_debug.c | 10 +-
mm/hugetlb.c | 340 +++++++++++++++++++++-------------------
mm/hugetlb_cgroup.c | 8 +-
6 files changed, 202 insertions(+), 179 deletions(-)
--
2.30.2
next reply other threads:[~2021-03-29 23:25 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-29 23:23 Mike Kravetz [this message]
2021-03-29 23:23 ` [PATCH v2 1/8] mm/cma: change cma mutex to irq safe spinlock Mike Kravetz
2021-03-30 1:13 ` Roman Gushchin
2021-03-30 1:20 ` Song Bao Hua (Barry Song)
2021-03-30 2:18 ` Mike Kravetz
2021-03-30 8:01 ` Michal Hocko
2021-03-30 8:08 ` [External] " Muchun Song
2021-03-30 8:17 ` Song Bao Hua (Barry Song)
2021-03-30 8:18 ` Michal Hocko
2021-03-30 8:21 ` Muchun Song
2021-03-31 2:37 ` Mike Kravetz
2021-03-29 23:23 ` [PATCH v2 2/8] hugetlb: no need to drop hugetlb_lock to call cma_release Mike Kravetz
2021-03-30 1:13 ` Roman Gushchin
2021-03-30 8:01 ` Michal Hocko
2021-03-29 23:23 ` [PATCH v2 3/8] hugetlb: add per-hstate mutex to synchronize user adjustments Mike Kravetz
2021-03-30 2:23 ` [External] " Muchun Song
2021-03-29 23:23 ` [PATCH v2 4/8] hugetlb: create remove_hugetlb_page() to separate functionality Mike Kravetz
2021-03-29 23:23 ` [PATCH v2 5/8] hugetlb: call update_and_free_page without hugetlb_lock Mike Kravetz
2021-03-30 2:10 ` Miaohe Lin
2021-03-30 2:21 ` [External] " Muchun Song
2021-03-31 2:39 ` Mike Kravetz
2021-03-29 23:24 ` [PATCH v2 6/8] hugetlb: change free_pool_huge_page to remove_pool_huge_page Mike Kravetz
2021-03-30 2:30 ` [External] " Muchun Song
2021-03-30 8:06 ` Michal Hocko
2021-03-29 23:24 ` [PATCH v2 7/8] hugetlb: make free_huge_page irq safe Mike Kravetz
2021-03-29 23:24 ` [PATCH v2 8/8] hugetlb: add lockdep_assert_held() calls for hugetlb_lock Mike Kravetz
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