From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, bp@alien8.de, bp@suse.de,
david@redhat.com, juew@google.com, linux-mm@kvack.org,
luto@kernel.org, mm-commits@vger.kernel.org,
naoya.horiguchi@nec.com, osalvador@suse.de,
stable@vger.kernel.org, tony.luck@intel.com,
torvalds@linux-foundation.org, yaoaili@kingsoft.com
Subject: [patch 18/24] mm/memory-failure: use a mutex to avoid memory_failure() races
Date: Thu, 24 Jun 2021 18:39:55 -0700 [thread overview]
Message-ID: <20210625013955.Ag67YQBoO%akpm@linux-foundation.org> (raw)
In-Reply-To: <20210624183838.ac3161ca4a43989665ac8b2f@linux-foundation.org>
From: Tony Luck <tony.luck@intel.com>
Subject: mm/memory-failure: use a mutex to avoid memory_failure() races
Patch series "mm,hwpoison: fix sending SIGBUS for Action Required MCE", v5.
I wrote this patchset to materialize what I think is the current allowable
solution mentioned by the previous discussion [1]. I simply borrowed
Tony's mutex patch and Aili's return code patch, then I queued another one
to find error virtual address in the best effort manner. I know that this
is not a perfect solution, but should work for some typical case.
[1]: https://lore.kernel.org/linux-mm/20210331192540.2141052f@alex-virtual-machine/
This patch (of 2):
There can be races when multiple CPUs consume poison from the same page.
The first into memory_failure() atomically sets the HWPoison page flag and
begins hunting for tasks that map this page. Eventually it invalidates
those mappings and may send a SIGBUS to the affected tasks.
But while all that work is going on, other CPUs see a "success" return
code from memory_failure() and so they believe the error has been handled
and continue executing.
Fix by wrapping most of the internal parts of memory_failure() in a mutex.
[akpm@linux-foundation.org: make mf_mutex local to memory_failure()]
Link: https://lkml.kernel.org/r/20210521030156.2612074-1-nao.horiguchi@gmail.com
Link: https://lkml.kernel.org/r/20210521030156.2612074-2-nao.horiguchi@gmail.com
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Aili Yao <yaoaili@kingsoft.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jue Wang <juew@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/memory-failure.c | 36 +++++++++++++++++++++++-------------
1 file changed, 23 insertions(+), 13 deletions(-)
--- a/mm/memory-failure.c~mm-memory-failure-use-a-mutex-to-avoid-memory_failure-races
+++ a/mm/memory-failure.c
@@ -1429,9 +1429,10 @@ int memory_failure(unsigned long pfn, in
struct page *hpage;
struct page *orig_head;
struct dev_pagemap *pgmap;
- int res;
+ int res = 0;
unsigned long page_flags;
bool retry = true;
+ static DEFINE_MUTEX(mf_mutex);
if (!sysctl_memory_failure_recovery)
panic("Memory failure on page %lx", pfn);
@@ -1449,13 +1450,18 @@ int memory_failure(unsigned long pfn, in
return -ENXIO;
}
+ mutex_lock(&mf_mutex);
+
try_again:
- if (PageHuge(p))
- return memory_failure_hugetlb(pfn, flags);
+ if (PageHuge(p)) {
+ res = memory_failure_hugetlb(pfn, flags);
+ goto unlock_mutex;
+ }
+
if (TestSetPageHWPoison(p)) {
pr_err("Memory failure: %#lx: already hardware poisoned\n",
pfn);
- return 0;
+ goto unlock_mutex;
}
orig_head = hpage = compound_head(p);
@@ -1488,17 +1494,19 @@ try_again:
res = MF_FAILED;
}
action_result(pfn, MF_MSG_BUDDY, res);
- return res == MF_RECOVERED ? 0 : -EBUSY;
+ res = res == MF_RECOVERED ? 0 : -EBUSY;
} else {
action_result(pfn, MF_MSG_KERNEL_HIGH_ORDER, MF_IGNORED);
- return -EBUSY;
+ res = -EBUSY;
}
+ goto unlock_mutex;
}
if (PageTransHuge(hpage)) {
if (try_to_split_thp_page(p, "Memory Failure") < 0) {
action_result(pfn, MF_MSG_UNSPLIT_THP, MF_IGNORED);
- return -EBUSY;
+ res = -EBUSY;
+ goto unlock_mutex;
}
VM_BUG_ON_PAGE(!page_count(p), p);
}
@@ -1522,7 +1530,7 @@ try_again:
if (PageCompound(p) && compound_head(p) != orig_head) {
action_result(pfn, MF_MSG_DIFFERENT_COMPOUND, MF_IGNORED);
res = -EBUSY;
- goto out;
+ goto unlock_page;
}
/*
@@ -1542,14 +1550,14 @@ try_again:
num_poisoned_pages_dec();
unlock_page(p);
put_page(p);
- return 0;
+ goto unlock_mutex;
}
if (hwpoison_filter(p)) {
if (TestClearPageHWPoison(p))
num_poisoned_pages_dec();
unlock_page(p);
put_page(p);
- return 0;
+ goto unlock_mutex;
}
/*
@@ -1573,7 +1581,7 @@ try_again:
if (!hwpoison_user_mappings(p, pfn, flags, &p)) {
action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED);
res = -EBUSY;
- goto out;
+ goto unlock_page;
}
/*
@@ -1582,13 +1590,15 @@ try_again:
if (PageLRU(p) && !PageSwapCache(p) && p->mapping == NULL) {
action_result(pfn, MF_MSG_TRUNCATED_LRU, MF_IGNORED);
res = -EBUSY;
- goto out;
+ goto unlock_page;
}
identify_page_state:
res = identify_page_state(pfn, p, page_flags);
-out:
+unlock_page:
unlock_page(p);
+unlock_mutex:
+ mutex_unlock(&mf_mutex);
return res;
}
EXPORT_SYMBOL_GPL(memory_failure);
_
next prev parent reply other threads:[~2021-06-25 1:39 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-25 1:38 incoming Andrew Morton
2021-06-25 1:39 ` [patch 01/24] mm: page_vma_mapped_walk(): use page for pvmw->page Andrew Morton
2021-06-25 1:39 ` [patch 02/24] mm: page_vma_mapped_walk(): settle PageHuge on entry Andrew Morton
2021-06-25 1:39 ` [patch 03/24] mm: page_vma_mapped_walk(): use pmde for *pvmw->pmd Andrew Morton
2021-06-25 1:39 ` [patch 04/24] mm: page_vma_mapped_walk(): prettify PVMW_MIGRATION block Andrew Morton
2021-06-25 1:39 ` [patch 05/24] mm: page_vma_mapped_walk(): crossing page table boundary Andrew Morton
2021-06-25 1:39 ` [patch 06/24] mm: page_vma_mapped_walk(): add a level of indentation Andrew Morton
2021-06-25 1:39 ` [patch 07/24] mm: page_vma_mapped_walk(): use goto instead of while (1) Andrew Morton
2021-06-25 1:39 ` [patch 08/24] mm: page_vma_mapped_walk(): get vma_address_end() earlier Andrew Morton
2021-06-25 1:39 ` [patch 09/24] mm/thp: fix page_vma_mapped_walk() if THP mapped by ptes Andrew Morton
2021-06-25 1:39 ` [patch 10/24] mm/thp: another PVMW_SYNC fix in page_vma_mapped_walk() Andrew Morton
2021-06-25 1:39 ` [patch 11/24] nilfs2: fix memory leak in nilfs_sysfs_delete_device_group Andrew Morton
2021-06-25 1:39 ` [patch 12/24] mm/vmalloc: add vmalloc_no_huge Andrew Morton
2021-06-25 1:39 ` [patch 13/24] KVM: s390: prepare for hugepage vmalloc Andrew Morton
2021-06-25 1:39 ` [patch 14/24] mm/vmalloc: unbreak kasan vmalloc support Andrew Morton
2021-06-25 1:39 ` [patch 15/24] kthread_worker: split code for canceling the delayed work timer Andrew Morton
2021-06-25 1:39 ` [patch 16/24] kthread: prevent deadlock when kthread_mod_delayed_work() races with kthread_cancel_delayed_work_sync() Andrew Morton
2021-06-25 1:39 ` [patch 17/24] mm, futex: fix shared futex pgoff on shmem huge page Andrew Morton
2021-06-25 1:39 ` Andrew Morton [this message]
2021-06-25 1:39 ` [patch 19/24] mm,hwpoison: return -EHWPOISON to denote that the page has already been poisoned Andrew Morton
2021-06-25 1:40 ` [patch 20/24] mm/hwpoison: do not lock page again when me_huge_page() successfully recovers Andrew Morton
2021-06-25 1:40 ` [patch 21/24] mm/page_alloc: __alloc_pages_bulk(): do bounds check before accessing array Andrew Morton
2021-06-25 1:40 ` [patch 22/24] mm/page_alloc: do bulk array bounds check after checking populated elements Andrew Morton
2021-06-25 1:40 ` [patch 23/24] MAINTAINERS: fix Marek's identity again Andrew Morton
2021-06-25 1:40 ` [patch 24/24] mailmap: add Marek's other e-mail address and identity without diacritics Andrew Morton
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