Messages in this thread | | | From | Dmitry Vyukov <> | Date | Tue, 7 Apr 2020 12:39:28 +0200 | Subject | Re: KCSAN: data-race in __fat_write_inode / fat12_ent_get |
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On Sat, Apr 4, 2020 at 8:14 AM OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> wrote: > > Dmitry Vyukov <dvyukov@google.com> writes: > > > On Fri, Apr 3, 2020 at 3:36 PM OGAWA Hirofumi > > <hirofumi@mail.parknet.co.jp> wrote: > >> > >> Hm, looks like the race between a directory entry vs a FAT entry. This > >> bug was happened with the corrupted image? Or the image passes the check > >> of dosfsck? > >> > >> If the corrupted image, it may be hard to prevent the all races. Well, > >> anyway, the corrupted image of the report will help to detect this > >> corruption. > > > > From the log, it's this program. > > My bet on a corrupted image. syzkaller does not have format > > descriptions for fat, so it's just random bytes. > > You meant I can regenerate a disk image from that log (if so, how)? > > If not, for next time, it would be helpful if syzkaller provides the log > to regenerate the corrupted image (or saving a corrupted image) to > reproduce this, then I can try to detect the corruption pattern early.
I've converted the program to C using syz-prog2c: https://github.com/google/syzkaller/blob/master/docs/syzbot.md#syzkaller-reproducers then slightly changed the generated program to dump the file to disk rather than mounting.
The resulting image is attached (archived because it's mostly zeros). [unhandled content-type:application/gzip] | |