From: Ma Wupeng mawupeng1@huawei.com

hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I6RKHX

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After the fork operation, it is erroneous for the child process to have a reliable page size twice that of its parent process.

Upon examining the mm_struct structure, it was discovered that reliable_nr_page should be initialized to 0, similar to how RSS is initialized during mm_init(). This particular problem that arises during forking is merely one such example.

To resolve this issue, it is recommended to set reliable_nr_page to 0 during the mm_init() operation.

Fixes: 8fc2546f8508 ("proc: mem_reliable: Count reliable memory usage of reliable tasks") Signed-off-by: Ma Wupeng mawupeng1@huawei.com --- include/linux/mem_reliable.h | 9 +++++++++ kernel/fork.c | 1 + 2 files changed, 10 insertions(+)

diff --git a/include/linux/mem_reliable.h b/include/linux/mem_reliable.h index d8cabf94f4a32..1e928ff69d997 100644 --- a/include/linux/mem_reliable.h +++ b/include/linux/mem_reliable.h @@ -216,6 +216,14 @@ static inline void add_reliable_page_counter(struct page *page,

reliable_page_counter_inner(mm, val); } + +static inline void reliable_clear_page_counter(struct mm_struct *mm) +{ + if (!mem_reliable_is_enabled()) + return; + + atomic_long_set(&mm->reliable_nr_page, 0); +} #else #define reliable_enabled 0

@@ -259,6 +267,7 @@ static inline void add_reliable_folio_counter(struct folio *folio, struct mm_struct *mm, int val) {} static inline void reliable_report_usage(struct seq_file *m, struct mm_struct *mm) {} +static inline void reliable_clear_page_counter(struct mm_struct *mm) {} #endif

#endif diff --git a/kernel/fork.c b/kernel/fork.c index e033388b11bd9..27d605c64b45d 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1326,6 +1326,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, mm->locked_vm = 0; atomic64_set(&mm->pinned_vm, 0); memset(&mm->rss_stat, 0, sizeof(mm->rss_stat)); + reliable_clear_page_counter(mm); spin_lock_init(&mm->page_table_lock); spin_lock_init(&mm->arg_lock); mm_init_cpumask(mm);