From: Jaegeuk Kim jaegeuk@kernel.org
[ Upstream commit 86f33603f8c51537265ff7ac0320638fd2cbdb1b ]
First problem is we hit BUG_ON() in f2fs_get_sum_page given EIO on f2fs_get_meta_page_nofail().
Quick fix was not to give any error with infinite loop, but syzbot caught a case where it goes to that loop from fuzzed image. In turned out we abused f2fs_get_meta_page_nofail() like in the below call stack.
- f2fs_fill_super - f2fs_build_segment_manager - build_sit_entries - get_current_sit_page
INFO: task syz-executor178:6870 can't die for more than 143 seconds. task:syz-executor178 state:R stack:26960 pid: 6870 ppid: 6869 flags:0x00004006 Call Trace:
Showing all locks held in the system: 1 lock held by khungtaskd/1179: #0: ffffffff8a554da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6242 1 lock held by systemd-journal/3920: 1 lock held by in:imklog/6769: #0: ffff88809eebc130 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:930 1 lock held by syz-executor178/6870: #0: ffff8880925120e0 (&type->s_umount_key#47/1){+.+.}-{3:3}, at: alloc_super+0x201/0xaf0 fs/super.c:229
Actually, we didn't have to use _nofail in this case, since we could return error to mount(2) already with the error handler.
As a result, this patch tries to 1) remove _nofail callers as much as possible, 2) deal with error case in last remaining caller, f2fs_get_sum_page().
Reported-by: syzbot+ee250ac8137be41d7b13@syzkaller.appspotmail.com Reviewed-by: Chao Yu yuchao0@huawei.com Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/f2fs/checkpoint.c | 2 +- fs/f2fs/f2fs.h | 2 +- fs/f2fs/node.c | 2 +- fs/f2fs/segment.c | 12 +++++++++--- 4 files changed, 12 insertions(+), 6 deletions(-)
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c index 8270e924b9777..83acd51bea13d 100644 --- a/fs/f2fs/checkpoint.c +++ b/fs/f2fs/checkpoint.c @@ -107,7 +107,7 @@ struct page *f2fs_get_meta_page(struct f2fs_sb_info *sbi, pgoff_t index) return __get_meta_page(sbi, index, true); }
-struct page *f2fs_get_meta_page_nofail(struct f2fs_sb_info *sbi, pgoff_t index) +struct page *f2fs_get_meta_page_retry(struct f2fs_sb_info *sbi, pgoff_t index) { struct page *page; int count = 0; diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index f03c573e427a5..3713d1c453592 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -3377,7 +3377,7 @@ enum rw_hint f2fs_io_type_to_rw_hint(struct f2fs_sb_info *sbi, void f2fs_stop_checkpoint(struct f2fs_sb_info *sbi, bool end_io); struct page *f2fs_grab_meta_page(struct f2fs_sb_info *sbi, pgoff_t index); struct page *f2fs_get_meta_page(struct f2fs_sb_info *sbi, pgoff_t index); -struct page *f2fs_get_meta_page_nofail(struct f2fs_sb_info *sbi, pgoff_t index); +struct page *f2fs_get_meta_page_retry(struct f2fs_sb_info *sbi, pgoff_t index); struct page *f2fs_get_tmp_page(struct f2fs_sb_info *sbi, pgoff_t index); bool f2fs_is_valid_blkaddr(struct f2fs_sb_info *sbi, block_t blkaddr, int type); diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index 0fde35611df18..6196117923bca 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -109,7 +109,7 @@ static void clear_node_page_dirty(struct page *page)
static struct page *get_current_nat_page(struct f2fs_sb_info *sbi, nid_t nid) { - return f2fs_get_meta_page_nofail(sbi, current_nat_addr(sbi, nid)); + return f2fs_get_meta_page(sbi, current_nat_addr(sbi, nid)); }
static struct page *get_next_nat_page(struct f2fs_sb_info *sbi, nid_t nid) diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 196f315035118..f41b475aa4aad 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -2318,7 +2318,9 @@ int f2fs_npages_for_summary_flush(struct f2fs_sb_info *sbi, bool for_ra) */ struct page *f2fs_get_sum_page(struct f2fs_sb_info *sbi, unsigned int segno) { - return f2fs_get_meta_page_nofail(sbi, GET_SUM_BLOCK(sbi, segno)); + if (unlikely(f2fs_cp_error(sbi))) + return ERR_PTR(-EIO); + return f2fs_get_meta_page_retry(sbi, GET_SUM_BLOCK(sbi, segno)); }
void f2fs_update_meta_page(struct f2fs_sb_info *sbi, @@ -2590,7 +2592,11 @@ static void change_curseg(struct f2fs_sb_info *sbi, int type) __next_free_blkoff(sbi, curseg, 0);
sum_page = f2fs_get_sum_page(sbi, new_segno); - f2fs_bug_on(sbi, IS_ERR(sum_page)); + if (IS_ERR(sum_page)) { + /* GC won't be able to use stale summary pages by cp_error */ + memset(curseg->sum_blk, 0, SUM_ENTRY_SIZE); + return; + } sum_node = (struct f2fs_summary_block *)page_address(sum_page); memcpy(curseg->sum_blk, sum_node, SUM_ENTRY_SIZE); f2fs_put_page(sum_page, 1); @@ -3759,7 +3765,7 @@ int f2fs_lookup_journal_in_cursum(struct f2fs_journal *journal, int type, static struct page *get_current_sit_page(struct f2fs_sb_info *sbi, unsigned int segno) { - return f2fs_get_meta_page_nofail(sbi, current_sit_addr(sbi, segno)); + return f2fs_get_meta_page(sbi, current_sit_addr(sbi, segno)); }
static struct page *get_next_sit_page(struct f2fs_sb_info *sbi,