Messages in this thread Patch in this message | | | From | Dongliang Mu <> | Date | Sat, 9 Apr 2022 14:42:29 +0800 | Subject | Re: [PATCH] fs: f2fs: remove WARN_ON in f2fs_is_valid_blkaddr |
| |
On Sat, Apr 9, 2022 at 11:46 AM Chao Yu <chao@kernel.org> wrote: > > On 2022/4/9 9:34, Dongliang Mu wrote: > > On Sat, Apr 9, 2022 at 8:27 AM Chao Yu <chao@kernel.org> wrote: > >> > >> On 2022/4/8 13:22, Dongliang Mu wrote: > >>> From: Dongliang Mu <mudongliangabcd@gmail.com> > >>> > >>> In f2fs_is_valid_blkaddr, if type is DATA_GENERIC_ENHANCE or > >>> DATA_GENERIC_ENHANCE_READ, it invokes WARN_ON(1) not matter > >>> blkaddr is in the range or not. > >> > >> If we run into the path where we invoke WARN_ON(1) in f2fs_is_valid_blkaddr(), > >> It means f2fs image may be broken, or there is a bug in f2fs. > >> > >> So, do you suffer any related issue in your environment? > > > > related issue? Can you explain a little? > > > > If you mean if this warning occurs, any other issues or crash > > I mean have you seen any warning info printed in the path of > f2fs_is_valid_blkaddr() before applying this patch, and if so, w/ what > reproducer? or you just figure out this patch from perspective of code > review?
Yes, I have seen both warning information from Syzbot [1] and my local syzkaller instance.
In f2fs_is_valid_blkaddr, if the following condition is satisfied, i.e., blkaddr is not in the right range [2], it will directly invoke one WARN_ON.
if (unlikely(blkaddr >= MAX_BLKADDR(sbi) || blkaddr < MAIN_BLKADDR(sbi))) {
This is the case on Syzbot.
Otherwise, it will jump into __is_bitmap_valid. And if the following condition is satisfied [3], it will trigger another WARN_ON.
exist = f2fs_test_bit(offset, se->cur_valid_map); if (!exist && type == DATA_GENERIC_ENHANCE) {
This appears in my local syzbot instance, but unfortunately it does not get any reproducer.
[1] https://syzkaller.appspot.com/bug?extid=763ae12a2ede1d99d4dc [2] https://elixir.bootlin.com/linux/latest/source/fs/f2fs/checkpoint.c#L187 [3] https://elixir.bootlin.com/linux/latest/source/fs/f2fs/checkpoint.c#L135
> > Thanks, > > > behaviors are generated? I tested on the syzbot. After removing the > > WARN_ON, there is no abnormal issue or crash behaviors followed with > > the corresponding reproducer. > > > > > >> > >> Thanks, > >> > >>> > >>> Fix this by removing WARN_ON. > >>> > >>> Note that, syzbot patch testing does not incur any further issues > >>> > >>> Reported-by: syzbot+763ae12a2ede1d99d4dc@syzkaller.appspotmail.com > >>> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com> > >>> --- > >>> fs/f2fs/checkpoint.c | 2 -- > >>> 1 file changed, 2 deletions(-) > >>> > >>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c > >>> index f5366feea82d..521498b2dd8c 100644 > >>> --- a/fs/f2fs/checkpoint.c > >>> +++ b/fs/f2fs/checkpoint.c > >>> @@ -158,7 +158,6 @@ static bool __is_bitmap_valid(struct f2fs_sb_info *sbi, block_t blkaddr, > >>> f2fs_err(sbi, "Inconsistent error blkaddr:%u, sit bitmap:%d", > >>> blkaddr, exist); > >>> set_sbi_flag(sbi, SBI_NEED_FSCK); > >>> - WARN_ON(1); > >>> } > >>> return exist; > >>> } > >>> @@ -196,7 +195,6 @@ bool f2fs_is_valid_blkaddr(struct f2fs_sb_info *sbi, > >>> f2fs_warn(sbi, "access invalid blkaddr:%u", > >>> blkaddr); > >>> set_sbi_flag(sbi, SBI_NEED_FSCK); > >>> - WARN_ON(1); > >>> return false; > >>> } else { > >>> return __is_bitmap_valid(sbi, blkaddr, type);
| |