The patch titled
Subject: fs-proc-task_mmuc-dont-read-mapcount-for-migration-entry-v4
has been removed from the -mm tree. Its filename was
fs-proc-task_mmuc-dont-read-mapcount-for-migration-entry-v4.patch
This patch was dropped because it was folded into fs-proc-task_mmuc-dont-read-mapcount-for-migration-entry.patch
------------------------------------------------------
From: Yang Shi <shy828301(a)gmail.com>
Subject: fs-proc-task_mmuc-dont-read-mapcount-for-migration-entry-v4
v4: * s/Treated/Treat per David
* Collected acked-by tag from David
v3: * Fixed the fix tag, the one used by v2 was not accurate
* Added comment about the risk calling page_mapcount() per David
* Fix pagemap
Link: https://lkml.kernel.org/r/20220203182641.824731-1-shy828301@gmail.com
Fixes: e9b61f19858a ("thp: reintroduce split_huge_page()")
Signed-off-by: Yang Shi <shy828301(a)gmail.com>
Reported-by: syzbot+1f52b3a18d5633fa7f82(a)syzkaller.appspotmail.com
Acked-by: David Hildenbrand <david(a)redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov(a)linux.intel.com>
Cc: Jann Horn <jannh(a)google.com>
Cc: Matthew Wilcox <willy(a)infradead.org>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
--- a/fs/proc/task_mmu.c~fs-proc-task_mmuc-dont-read-mapcount-for-migration-entry-v4
+++ a/fs/proc/task_mmu.c
@@ -469,9 +469,12 @@ static void smaps_account(struct mem_siz
* If any subpage of the compound page mapped with PTE it would elevate
* page_count().
*
- * Treated regular migration entries as mapcount == 1 without reading
- * mapcount since calling page_mapcount() for migration entries is
- * racy against THP splitting.
+ * The page_mapcount() is called to get a snapshot of the mapcount.
+ * Without holding the page lock this snapshot can be slightly wrong as
+ * we cannot always read the mapcount atomically. It is not safe to
+ * call page_mapcount() even with PTL held if the page is not mapped,
+ * especially for migration entries. Treat regular migration entries
+ * as mapcount == 1.
*/
if ((page_count(page) == 1) || migration) {
smaps_page_accumulate(mss, page, size, size << PSS_SHIFT, dirty,
@@ -1393,6 +1396,7 @@ static pagemap_entry_t pte_to_pagemap_en
{
u64 frame = 0, flags = 0;
struct page *page = NULL;
+ bool migration = false;
if (pte_present(pte)) {
if (pm->show_pfn)
@@ -1414,13 +1418,14 @@ static pagemap_entry_t pte_to_pagemap_en
frame = swp_type(entry) |
(swp_offset(entry) << MAX_SWAPFILES_SHIFT);
flags |= PM_SWAP;
+ migration = is_migration_entry(entry);
if (is_pfn_swap_entry(entry))
page = pfn_swap_entry_to_page(entry);
}
if (page && !PageAnon(page))
flags |= PM_FILE;
- if (page && page_mapcount(page) == 1)
+ if (page && !migration && page_mapcount(page) == 1)
flags |= PM_MMAP_EXCLUSIVE;
if (vma->vm_flags & VM_SOFTDIRTY)
flags |= PM_SOFT_DIRTY;
@@ -1436,6 +1441,7 @@ static int pagemap_pmd_range(pmd_t *pmdp
spinlock_t *ptl;
pte_t *pte, *orig_pte;
int err = 0;
+ bool migration = false;
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
ptl = pmd_trans_huge_lock(pmdp, vma);
@@ -1476,11 +1482,12 @@ static int pagemap_pmd_range(pmd_t *pmdp
if (pmd_swp_uffd_wp(pmd))
flags |= PM_UFFD_WP;
VM_BUG_ON(!is_pmd_migration_entry(pmd));
+ migration = is_migration_entry(entry);
page = pfn_swap_entry_to_page(entry);
}
#endif
- if (page && page_mapcount(page) == 1)
+ if (page && !migration && page_mapcount(page) == 1)
flags |= PM_MMAP_EXCLUSIVE;
for (; addr != end; addr += PAGE_SIZE) {
_
Patches currently in -mm which might be from shy828301(a)gmail.com are
fs-proc-task_mmuc-dont-read-mapcount-for-migration-entry.patch
The patch titled
Subject: hugetlbfs: fix a truncation issue in hugepages parameter
has been added to the -mm tree. Its filename is
hugetlbfs-fix-a-truncation-issue-in-hugepages-parameter.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/hugetlbfs-fix-a-truncation-issue-…
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/hugetlbfs-fix-a-truncation-issue-…
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Liu Yuntao <liuyuntao10(a)huawei.com>
Subject: hugetlbfs: fix a truncation issue in hugepages parameter
When we specify a large number for node in hugepages parameter, it may be
parsed to another number due to truncation in this statement:
node = tmp;
For example, add following parameter in command line:
hugepagesz=1G hugepages=4294967297:5
and kernel will allocate 5 hugepages for node 1 instead of ignoring it.
I move the validation check earlier to fix this issue, and slightly
simplifies the condition here.
Link: https://lkml.kernel.org/r/20220209134018.8242-1-liuyuntao10@huawei.com
Fixes: b5389086ad7be0 ("hugetlbfs: extend the definition of hugepages parameter to support node allocation")
Signed-off-by: Liu Yuntao <liuyuntao10(a)huawei.com>
Reviewed-by: Mike Kravetz <mike.kravetz(a)oracle.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
--- a/mm/hugetlb.c~hugetlbfs-fix-a-truncation-issue-in-hugepages-parameter
+++ a/mm/hugetlb.c
@@ -4159,10 +4159,10 @@ static int __init hugepages_setup(char *
pr_warn("HugeTLB: architecture can't support node specific alloc, ignoring!\n");
return 0;
}
+ if (tmp >= nr_online_nodes)
+ goto invalid;
node = tmp;
p += count + 1;
- if (node < 0 || node >= nr_online_nodes)
- goto invalid;
/* Parse hugepages */
if (sscanf(p, "%lu%n", &tmp, &count) != 1)
goto invalid;
_
Patches currently in -mm which might be from liuyuntao10(a)huawei.com are
hugetlbfs-fix-a-truncation-issue-in-hugepages-parameter.patch