* FAILED: patch "[PATCH] mm/hugetlb: initialize hugetlb_usage in mm_init" failed to apply to 4.4-stable tree
@ 2021-09-16 12:56 gregkh
0 siblings, 0 replies; only message in thread
From: gregkh @ 2021-09-16 12:56 UTC (permalink / raw)
To: liuzixian4, akpm, mike.kravetz, naoya.horiguchi, stable, torvalds; +Cc: stable
The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 13db8c50477d83ad3e3b9b0ae247e5cd833a7ae4 Mon Sep 17 00:00:00 2001
From: Liu Zixian <liuzixian4@huawei.com>
Date: Wed, 8 Sep 2021 18:10:05 -0700
Subject: [PATCH] mm/hugetlb: initialize hugetlb_usage in mm_init
After fork, the child process will get incorrect (2x) hugetlb_usage. If
a process uses 5 2MB hugetlb pages in an anonymous mapping,
HugetlbPages: 10240 kB
and then forks, the child will show,
HugetlbPages: 20480 kB
The reason for double the amount is because hugetlb_usage will be copied
from the parent and then increased when we copy page tables from parent
to child. Child will have 2x actual usage.
Fix this by adding hugetlb_count_init in mm_init.
Link: https://lkml.kernel.org/r/20210826071742.877-1-liuzixian4@huawei.com
Fixes: 5d317b2b6536 ("mm: hugetlb: proc: add HugetlbPages field to /proc/PID/status")
Signed-off-by: Liu Zixian <liuzixian4@huawei.com>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index f7ca1a3870ea..1faebe1cd0ed 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -858,6 +858,11 @@ static inline spinlock_t *huge_pte_lockptr(struct hstate *h,
void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm);
+static inline void hugetlb_count_init(struct mm_struct *mm)
+{
+ atomic_long_set(&mm->hugetlb_usage, 0);
+}
+
static inline void hugetlb_count_add(long l, struct mm_struct *mm)
{
atomic_long_add(l, &mm->hugetlb_usage);
@@ -1042,6 +1047,10 @@ static inline spinlock_t *huge_pte_lockptr(struct hstate *h,
return &mm->page_table_lock;
}
+static inline void hugetlb_count_init(struct mm_struct *mm)
+{
+}
+
static inline void hugetlb_report_usage(struct seq_file *f, struct mm_struct *m)
{
}
diff --git a/kernel/fork.c b/kernel/fork.c
index ff5be23800af..38681ad44c76 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1063,6 +1063,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
mm->pmd_huge_pte = NULL;
#endif
mm_init_uprobes_state(mm);
+ hugetlb_count_init(mm);
if (current->mm) {
mm->flags = current->mm->flags & MMF_INIT_MASK;
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2021-09-16 12:56 FAILED: patch "[PATCH] mm/hugetlb: initialize hugetlb_usage in mm_init" failed to apply to 4.4-stable tree gregkh
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