On Oct 22, 2024, at 11:05, Hongbo Li <[email protected]> wrote: > > > > On 2024/10/22 10:38, Alan Huang wrote: >> On Oct 22, 2024, at 10:26, Hongbo Li <[email protected]> wrote: >>> >>> >>> >>> On 2024/10/21 23:43, Jeongjun Park wrote: >>>> The size of a.data_type is set abnormally large, causing >>>> shift-out-of-bounds. >>>> To fix this, we need to add validation on a.data_type in >>>> alloc_lru_idx_fragmentation(). >>>> Reported-by: [email protected] >>>> Fixes: 260af1562ec1 ("bcachefs: Kill alloc_v4.fragmentation_lru") >>>> Signed-off-by: Jeongjun Park <[email protected]> >>>> --- >>>> fs/bcachefs/alloc_background.h | 3 +++ >>>> 1 file changed, 3 insertions(+) >>>> diff --git a/fs/bcachefs/alloc_background.h >>>> b/fs/bcachefs/alloc_background.h >>>> index f8e87c6721b1..163a67b97a40 100644 >>>> --- a/fs/bcachefs/alloc_background.h >>>> +++ b/fs/bcachefs/alloc_background.h >>>> @@ -168,6 +168,9 @@ static inline bool data_type_movable(enum >>>> bch_data_type type) >>>> static inline u64 alloc_lru_idx_fragmentation(struct bch_alloc_v4 a, >>>> struct bch_dev *ca) >>>> { >>>> + if (a.data_type >= BCH_DATA_NR) >>>> + return 0; >>>> + >>> >>> oh, I found I have done the same thing in [1]("Re: [syzbot] [bcachefs?] >>> UBSAN: shift-out-of-bounds in bch2_alloc_to_text"). But >> Your patch there is still triggering the issue. > Yeah, it just notify the issue and not prevent the issue. So I found it > should add a.data_type condition indeed. :) >>> in my humble opinion, the validation changes also should be added. And in >>> addition, move the condition about a.data_type into >> There is already the validation: >> bkey_fsck_err_on(alloc_data_type(a, a.data_type) != a.data_type > > This is actually not enough. This only do some transition check. For example, > if a.data_type break when bch2_bucket_sectors_dirty (the data corruption can > lead to various situations occurring) is true, the helper does noting.
Make sense. > > Thanks, > Hongbo > >> And the unknown data type is already printed in bch2_prt_data_type, >> additional validation doesn’t help much. >>> data_type_movable will be better. Just my personal opinion.:) >> In my personal opinion, I don’t think so :) >>> >>> [1] https://www.spinics.net/lists/kernel/msg5412619.html >>> >>> Thanks, >>> Hongbo >>> >>>> if (!data_type_movable(a.data_type) || >>>> !bch2_bucket_sectors_fragmented(ca, a)) >>>> return 0; >>>> --
