Messages in this thread | | | Subject | Re: [f2fs-dev] [PATCH v3] f2fs: handle errors of f2fs_get_meta_page_nofail be failed | From | Chao Yu <> | Date | Wed, 14 Oct 2020 14:21:25 +0800 |
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On 2020/10/13 11:07, jaegeuk@kernel.org wrote: > 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 > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
I prefer to use f2fs_get_meta_page() as much as possible except change_curseg() path, however, it's minor, and the time is closing to merge window, so:
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Thanks,
> --- > > Change log from v2: > - avoid _nofail and add error handler > > 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 f18386d30f031..023462e80e58d 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 ae46d44bd5211..adda53d20a399 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -3422,7 +3422,7 @@ unsigned int f2fs_usable_blks_in_seg(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 93fb34d636eb5..d5d8ce077f295 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 13ecd2c2c361b..05ab5ae2b5f7f 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, >
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