hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IB0OV7 -------------------------------- This reverts commit 19e1c50695fc0ff8a34799ce4342b0e6f105d230. During our test, it is found that this will lead to NULL pointer dereference as follow: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 pc : __find_get_block_slow+0xbc/0x29c lr : __find_get_block_slow+0x50/0x29c Call trace: __find_get_block_slow+0xbc/0x29c __find_get_block+0xa8/0xd0 __getblk_gfp+0x30/0x84 ext4_getblk+0x90/0x244 [ext4] ext4_bread+0x1c/0x10c [ext4] __ext4_read_dirblock.part.0+0x48/0x32c [ext4] ext4_dx_find_entry+0xb0/0x220 [ext4] __ext4_find_entry+0x3f0/0x470 [ext4] ext4_lookup.part.0+0x5c/0x240 [ext4] ext4_lookup+0x2c/0x50 [ext4] lookup_open.isra.0+0x1d4/0x3c4 open_last_lookups+0x36c/0x3d0 path_openat+0x8c/0x1f0 do_filp_open+0x88/0x150 do_open_execat+0x78/0x1cc alloc_bprm+0x30/0x180 Revert this for a better solution. Fixes: 19e1c50695fc ("arm64: mm: add mc support for __buffer_migrate_page") Signed-off-by: Wupeng Ma <mawupeng1@huawei.com> --- mm/migrate.c | 12 +----------- 1 file changed, 1 insertion(+), 11 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 0d79382f9697..cf8c05ea821e 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -820,7 +820,6 @@ static int __buffer_migrate_page(struct address_space *mapping, struct buffer_head *bh, *head; int rc; int expected_count; - bool copy_done = false; if (!page_has_buffers(page)) return migrate_page(mapping, newpage, page, mode); @@ -861,13 +860,7 @@ static int __buffer_migrate_page(struct address_space *mapping, } } - if (IS_ENABLED(CONFIG_ARM64) && IS_ENABLED(CONFIG_ARCH_HAS_COPY_MC) && - (mode != MIGRATE_SYNC_NO_COPY)) { - rc = migrate_page_mc_extra(mapping, newpage, page, mode, 0); - copy_done = true; - } else { - rc = migrate_page_move_mapping(mapping, newpage, page, 0); - } + rc = migrate_page_move_mapping(mapping, newpage, page, 0); if (rc != MIGRATEPAGE_SUCCESS) goto unlock_buffers; @@ -880,9 +873,6 @@ static int __buffer_migrate_page(struct address_space *mapping, } while (bh != head); - if (copy_done) - goto unlock_buffers; - if (mode != MIGRATE_SYNC_NO_COPY) migrate_page_copy(newpage, page); else -- 2.43.0