From: Wupeng Ma <mawupeng1@huawei.com> hulk inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/ID6J4B -------------------------------- When encountering memory faults during page migration on arm64 systems, this change ensures the faulting user process is terminated instead of causing a kernel panic. The implementation adds proper error handling for copy operations in migrate_page(). To enable this, bit 1 for uce_kernel_recovery should be enabled: - echo 1 > /proc/sys/kernel/uce_kernel_recovery Signed-off-by: Wupeng Ma <mawupeng1@huawei.com> --- mm/migrate.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 70 insertions(+), 9 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index f8c379a0b9b9..83f95fa8f4c5 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -47,6 +47,7 @@ #include <linux/page_owner.h> #include <linux/sched/mm.h> #include <linux/ptrace.h> +#include <linux/highmem.h> #include <asm/tlbflush.h> @@ -640,24 +641,33 @@ int migrate_huge_page_move_mapping(struct address_space *mapping, * arithmetic will work across the entire page. We need something more * specialized. */ -static void __copy_gigantic_page(struct page *dst, struct page *src, - int nr_pages) +static int __copy_gigantic_page(struct page *dst, struct page *src, + int nr_pages, bool mc) { - int i; + int i, ret = 0; struct page *dst_base = dst; struct page *src_base = src; for (i = 0; i < nr_pages; ) { cond_resched(); - copy_highpage(dst, src); + + if (mc) { + ret = copy_mc_highpage(dst, src); + if (ret) + return -EFAULT; + } else { + copy_highpage(dst, src); + } i++; dst = mem_map_next(dst, dst_base, i); src = mem_map_next(src, src_base, i); } + + return ret; } -static void copy_huge_page(struct page *dst, struct page *src) +static int __copy_huge_page(struct page *dst, struct page *src, bool mc) { int i; int nr_pages; @@ -667,20 +677,32 @@ static void copy_huge_page(struct page *dst, struct page *src) struct hstate *h = page_hstate(src); nr_pages = pages_per_huge_page(h); - if (unlikely(nr_pages > MAX_ORDER_NR_PAGES)) { - __copy_gigantic_page(dst, src, nr_pages); - return; - } + if (unlikely(nr_pages > MAX_ORDER_NR_PAGES)) + return __copy_gigantic_page(dst, src, nr_pages, mc); } else { /* thp page */ BUG_ON(!PageTransHuge(src)); nr_pages = hpage_nr_pages(src); } + if (mc) + return copy_mc_highpages(dst, src, nr_pages); + for (i = 0; i < nr_pages; i++) { cond_resched(); copy_highpage(dst + i, src + i); } + return 0; +} + +static int copy_huge_page(struct page *dst, struct page *src) +{ + return __copy_huge_page(dst, src, false); +} + +static int copy_mc_huge_page(struct page *dst, struct page *src) +{ + return __copy_huge_page(dst, src, true); } /* @@ -756,6 +778,38 @@ void migrate_page_copy(struct page *newpage, struct page *page) } EXPORT_SYMBOL(migrate_page_copy); +static int migrate_page_copy_mc(struct page *newpage, struct page *page) +{ + int rc; + + if (PageHuge(page) || PageTransHuge(page)) + rc = copy_mc_huge_page(newpage, page); + else + rc = copy_mc_highpage(newpage, page); + + return rc; +} + +static int migrate_page_mc_extra(struct address_space *mapping, + struct page *newpage, struct page *page, + enum migrate_mode mode, int extra_count) +{ + int rc; + + rc = migrate_page_copy_mc(newpage, page); + if (rc) + return rc; + + rc = migrate_page_move_mapping(mapping, newpage, page, NULL, mode, + extra_count); + if (rc != MIGRATEPAGE_SUCCESS) + return rc; + + migrate_page_states(newpage, page); + + return rc; +} + /************************************************************ * Migration functions ***********************************************************/ @@ -774,6 +828,13 @@ int migrate_page(struct address_space *mapping, BUG_ON(PageWriteback(page)); /* Writeback must be complete */ +#ifdef CONFIG_UCE_KERNEL_RECOVERY + if (IS_ENABLED(CONFIG_ARM64) && + is_cow_kernel_recovery_enable() && + (mode != MIGRATE_SYNC_NO_COPY)) + return migrate_page_mc_extra(mapping, newpage, page, mode, 0); +#endif + rc = migrate_page_move_mapping(mapping, newpage, page, NULL, mode, 0); if (rc != MIGRATEPAGE_SUCCESS) -- 2.33.0