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| author | Jaegeuk Kim <jaegeuk@kernel.org> | 2020-10-02 14:17:35 -0700 |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2020-10-13 23:23:29 -0700 |
| commit | 86f33603f8c51537265ff7ac0320638fd2cbdb1b (patch) | |
| tree | b5ba5cd2ab02948f1ec63eef016dfbe204d6fd59 /fs/f2fs/segment.c | |
| parent | d662fad143c0470ad7f46ea7b02da539f613d7d7 (diff) | |
| download | linux-86f33603f8c51537265ff7ac0320638fd2cbdb1b.tar.bz2 | |
f2fs: handle errors of f2fs_get_meta_page_nofail
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>
Diffstat (limited to 'fs/f2fs/segment.c')
| -rw-r--r-- | fs/f2fs/segment.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 13ecd2c2c361..05ab5ae2b5f7 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -2379,7 +2379,9 @@ 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, @@ -2669,7 +2671,11 @@ static void change_curseg(struct f2fs_sb_info *sbi, int type, bool flush) __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); @@ -3964,7 +3970,7 @@ 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, |