On Mon, Oct 11, 2021 at 06:58:52AM -0600, Jens Axboe wrote:
> On 10/11/21 4:27 AM, Luís Henriques wrote:
> > While running fstests generic/095 against ext4 on a zram device I started
> > seeing fio crashing. Fix it by making sure io_u->file isn't NULL before
> > accessing it.
> >
> > Signed-off-by: Luís Henriques <lhenriques@xxxxxxx>
> > ---
> > io_u.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/io_u.c b/io_u.c
> > index 5289b5d1d9c6..b8e715d4118c 100644
> > --- a/io_u.c
> > +++ b/io_u.c
> > @@ -2009,7 +2009,8 @@ static void io_completed(struct thread_data *td, struct io_u **io_u_ptr,
> > io_u->xfer_buf += bytes;
> > io_u->offset += bytes;
> > td->ts.short_io_u[io_u->ddir]++;
> > - if (io_u->offset < io_u->file->real_file_size) {
> > + if (io_u->file &&
> > + (io_u->offset < io_u->file->real_file_size)) {
> > requeue_io_u(td, io_u_ptr);
> > return;
> > }
>
> This will prevent the crash, but I'm wondering why io_u-> == NULL for this case.
> It really should be a valid file.
>
> Can you let me know exactly how you're reproducing this? Then I'll give it
> a whirl too.
Sure, here's my recipe for reproducing this bug:
# modprobe zram num_devices=2
# echo 1G > /sys/block/zram0/disksize
# echo 1G > /sys/block/zram1/disksize
# mkfs.ext4 /dev/zram0
# mkfs.ext4 /dev/zram1
# ./check generic/095
Cheers,
--
Luís
