On Mon, Jul 17, 2023 at 08:04:54PM +0530, Ritesh Harjani wrote:
>
> These can basically trigger in extremely low memory space and only when
> such ranges exist in the PA rbtree. Hence, I guess it is a little hard
> to tigger race.
Ritesh, thanks for looking into this!
Naresh, how easy is it for you to trigger the BUG when using LTP? I
did two xfstests runs using "gce-xfstests -c ext2/default -g auto",
one on the ext4 dev branch, and one on linux-next 20230717, and I
wasn't able to trigger the BUG.
If you can trivially trigger it using LTP (perhaps with a low memory
configuration in your test setup?), that would be useful to know.
Cheers,
- Ted
"Theodore Ts'o" <[email protected]> writes:
> On Mon, Jul 17, 2023 at 08:04:54PM +0530, Ritesh Harjani wrote:
>>
>> These can basically trigger in extremely low memory space and only when
>> such ranges exist in the PA rbtree. Hence, I guess it is a little hard
>> to tigger race.
>
> Ritesh, thanks for looking into this!
>
> Naresh, how easy is it for you to trigger the BUG when using LTP? I
> did two xfstests runs using "gce-xfstests -c ext2/default -g auto",
> one on the ext4 dev branch, and one on linux-next 20230717, and I
> wasn't able to trigger the BUG.
>
> If you can trivially trigger it using LTP (perhaps with a low memory
> configuration in your test setup?), that would be useful to know.
Hi Ted,
Sorry for wrong choice of words. By low memory space I meant low disk
space i.e. ENOSPC test (fs_fill). I reproduced it like this -
root@ubuntu:/opt/ltp# while [ 1 ]; do ./runltp -s fs_fill; sleep 1; done
For me it took around ~1-2 hours for it to reproduce when I tried again.
I am hoping if we run generic/269 (fsstress ENOSPC) in a while loop like
this maybe it can hit this bug. But I didn't give it a shot.
-ritesh
> "Theodore Ts'o" <[email protected]> writes:
> > On Mon, Jul 17, 2023 at 08:04:54PM +0530, Ritesh Harjani wrote:
> >> These can basically trigger in extremely low memory space and only when
> >> such ranges exist in the PA rbtree. Hence, I guess it is a little hard
> >> to tigger race.
> > Ritesh, thanks for looking into this!
> > Naresh, how easy is it for you to trigger the BUG when using LTP? I
> > did two xfstests runs using "gce-xfstests -c ext2/default -g auto",
> > one on the ext4 dev branch, and one on linux-next 20230717, and I
> > wasn't able to trigger the BUG.
> > If you can trivially trigger it using LTP (perhaps with a low memory
> > configuration in your test setup?), that would be useful to know.
> Hi Ted,
Hi Ted, Ritesh, all,
> Sorry for wrong choice of words. By low memory space I meant low disk
> space i.e. ENOSPC test (fs_fill). I reproduced it like this -
> root@ubuntu:/opt/ltp# while [ 1 ]; do ./runltp -s fs_fill; sleep 1; done
Late, but better than never: LTP C tests can be run without any wrapper.
e.g. to reproduce the bug triggered by fs_fill, you can just:
git clone https://github.com/linux-test-project/ltp.git && cd ltp
./ci/your-distro.sh # optionally install the dependencies
make autotools
./configure
cd testcases/kernel/fs/fs_fill/
make -j`nproc`
while true; do ./fs_fill; sleep 1; done
NOTE: runltp is
1) deprecated, replaced by runltp-ng [1]
2) again, there is no need to use this shell wrapper to run a single C binary
Kind regards,
Petr
[1] https://github.com/linux-test-project/runltp-ng
> For me it took around ~1-2 hours for it to reproduce when I tried again.
> I am hoping if we run generic/269 (fsstress ENOSPC) in a while loop like
> this maybe it can hit this bug. But I didn't give it a shot.
> -ritesh
On Tue, 18 Jul 2023 at 03:04, Theodore Ts'o <[email protected]> wrote:
>
> On Mon, Jul 17, 2023 at 08:04:54PM +0530, Ritesh Harjani wrote:
> >
> > These can basically trigger in extremely low memory space and only when
> > such ranges exist in the PA rbtree. Hence, I guess it is a little hard
> > to tigger race.
>
> Ritesh, thanks for looking into this!
>
> Naresh, how easy is it for you to trigger the BUG when using LTP? I
> did two xfstests runs using "gce-xfstests -c ext2/default -g auto",
> one on the ext4 dev branch, and one on linux-next 20230717, and I
> wasn't able to trigger the BUG.
>
> If you can trivially trigger it using LTP (perhaps with a low memory
> configuration in your test setup?), that would be useful to know.
In our setup it is not easy to reproduce with the same device and
same build on x86_4 and arm64 juno-r2 connected with SSD drive
and running LTP fs testing.
LTP fs_fill is triggering several ENOSPC before getting this reported
kernel BUG at fs/ext4/mballoc.c:4369!
The reported issues are not noticed on latest Linux next tags.
- Naresh
>
> Cheers,
>
> - Ted