notfound 969223 6.12.9-1
thanks
---

Hi Salvatore,

On Thu, Feb 20, 2025 at 04:41:54PM +0100, Salvatore Bonaccorso wrote:
> Hi
> On Thu, Feb 20, 2025 at 02:53:44PM +0100, Nicolas Schier wrote:
> > On Thu, Feb 20, 2025 at 01:20:29PM +0100 Salvatore Bonaccorso wrote:
> > > Control: tags -1 + moreinfo
> > > 
> > > Hi,
> > > 
> > > On Thu, Mar 11, 2021 at 07:09:43AM +0100, Nicolas Schier wrote:
> > > > On Wed 03 Mar 2021 22:50:44 GMT Shengjing Zhu wrote:
> > > > > On Wed, Mar 03, 2021 at 11:30:20AM +0100, Nicolas Schier wrote:
> > > > > > On Wed 03 Mar 2021 17:33:16 GMT Shengjing Zhu write:
> > > > > > > 
> > > > > > > On Wed, Mar 3, 2021 at 3:40 PM Nicolas Schier <nico...@fjasle.eu> 
> > > > > > > wrote:
> > > > > > > > > [2]: 
> > > > > > > > > https://lore.kernel.org/linux-unionfs/CAJfpegsiuf8ib5cvVrr=zhz+xu7bmmtt2eyapseudmpcrbu...@mail.gmail.com/T/#t
> > > > > > > >
> > > > > > > > The overlay fs patchset [2] has been merged and with v5.10.13 
> > > > > > > > (tested
> > > > > > > > on linux-image-5.10.0-3-arm64) the issue is no more 
> > > > > > > > reproducible for
> > > > > > > > me.  Might you want to re-check on your site?
> > > > > > > >
> > > > > > > 
> > > > > > > If I understand correctly, the upstream patch is merged into the 
> > > > > > > v5.11 tree.
> > > > > > 
> > > > > > Sorry.  Yes, you're right.
> > > > > > 
> > > > > > > And I still can reproduce the error on the Debian v5.10 kernel.
> > > > > > 
> > > > > > That confuses me quite a bit.  I did it once again on an ext4 mount 
> > > > > > (still the 5.10.0-3-arm64 kernel):
> > > > > > 
> > > > > >   nsc@lillesand:/tmp$ cat 
> > > > > > /sys/module/overlay/parameters/permit_mounts_in_userns 
> > > > > >   Y
> > > > > >   nsc@lillesand:/tmp$ mkdir -p test/lower/a test/merged test/upper 
> > > > > > test/work
> > > > > >   nsc@lillesand:/tmp$ uname -a | tee test/lower/a/a
> > > > > >   Linux lillesand 5.10.0-3-arm64 #1 SMP Debian 5.10.13-1 
> > > > > > (2021-02-06) aarch64 GNU/Linux
> > > > > >   nsc@lillesand:/tmp$ unshare -m -U -r
> > > > > >   root@lillesand:/tmp# mount -t overlay -o 
> > > > > > rw,lowerdir=/tmp/test/lower,upperdir=/tmp/test/upper,workdir=/tmp/test/work
> > > > > >  overlay /tmp/test/merged
> > > > > >   root@lillesand:/tmp# rm -rf test/merged/a
> > > > > >   root@lillesand:/tmp# find test -ls
> > > > > >     1597776      4 drwxr-xr-x   6 root     root         4096 mars  
> > > > > > 3 08:24 test
> > > > > >     1973978      4 drwxr-xr-x   2 root     root         4096 mars  
> > > > > > 3 08:27 test/upper
> > > > > >     2099881      0 c---------   1 root     root       0,   0 mars  
> > > > > > 3 08:27 test/upper/a
> > > > > >     1973978      4 drwxr-xr-x   1 root     root         4096 mars  
> > > > > > 3 08:27 test/merged
> > > > > >     1714388      4 drwxr-xr-x   3 root     root         4096 mars  
> > > > > > 3 08:24 test/lower
> > > > > >     1714389      4 drwxr-xr-x   2 root     root         4096 mars  
> > > > > > 3 08:27 test/lower/a
> > > > > >     1714393      4 -rw-r--r--   1 root     root           86 mars  
> > > > > > 3 10:48 test/lower/a/a
> > > > > >     1973979      4 drwxr-xr-x   3 root     root         4096 mars  
> > > > > > 3 10:48 test/work
> > > > > >     2099880      4 d---------   2 root     root         4096 mars  
> > > > > > 3 10:48 test/work/work
> > > > > >   root@lillesand:/tmp# 
> > > > > > 
> > > > > zsj@debian:~$ cat 
> > > > > /sys/module/overlay/parameters/permit_mounts_in_userns 
> > > > > Y
> > > > > zsj@debian:~/t$ mkdir -p test/lower/a test/merged test/upper test/work
> > > > > zsj@debian:~/t$ uname -a | tee test/lower/a/a
> > > > > Linux debian 5.10.0-3-amd64 #1 SMP Debian 5.10.13-1 (2021-02-06) 
> > > > > x86_64 GNU/Linux
> > > > > zsj@debian:~/t$ unshare -m -U -r
> > > > > root@debian:~/t# mount -t overlay -o 
> > > > > rw,lowerdir=./test/lower,upperdir=./test/upper,workdir=./test/work 
> > > > > overlay ./test/merged/
> > > > > root@debian:~/t# rm -rf ./test/merged/a
> > > > > rm: cannot remove './test/merged/a': Input/output error
> > > > > root@debian:~/t# find test -ls
> > > > >   7350352      4 drwxr-xr-x   6 root     root         4096 Mar  3 
> > > > > 22:44 test
> > > > >   7351341      4 drwxr-xr-x   3 root     root         4096 Mar  3 
> > > > > 22:44 test/lower
> > > > >   7353492      4 drwxr-xr-x   2 root     root         4096 Mar  3 
> > > > > 22:44 test/lower/a
> > > > >   7356441      4 -rw-r--r--   1 root     root           82 Mar  3 
> > > > > 22:44 test/lower/a/a
> > > > >   7356069      4 drwxr-xr-x   3 root     root         4096 Mar  3 
> > > > > 22:45 test/work
> > > > >   7358324      4 d---------   2 root     root         4096 Mar  3 
> > > > > 22:45 test/work/work
> > > > >   7358564      0 c---------   2 root     root       0,   0 Mar  3 
> > > > > 22:45 test/work/work/#4
> > > > >   7354400      4 drwxr-xr-x   3 root     root         4096 Mar  3 
> > > > > 22:44 test/upper
> > > > >   7358563      4 drwxr-xr-x   2 root     root         4096 Mar  3 
> > > > > 22:45 test/upper/a
> > > > >   7358564      0 c---------   2 root     root       0,   0 Mar  3 
> > > > > 22:45 test/upper/a/a
> > > > >   7354400      4 drwxr-xr-x   1 root     root         4096 Mar  3 
> > > > > 22:44 test/merged
> > > > >   7353492      4 drwxr-xr-x   1 root     root         4096 Mar  3 
> > > > > 22:45 test/merged/a
> > > > > 
> > > > > > Do you see any kernel log message from overlay fs?  Might it depend 
> > > > > > on 
> > > > > > the underlying filesystem? Can you create a white-out char dev node 
> > > > > > manually?
> > > > > > 
> > > > > 
> > > > > [1215353.859717] Setting dangerous option permit_mounts_in_userns - 
> > > > > tainting kernel
> > > > > [1215353.859841] overlayfs: overlayfs: Allowing overlay mounts in 
> > > > > user namespaces bears security risks
> > > > > [1215425.416543] overlayfs: upper fs does not support xattr, falling 
> > > > > back to index=off and metacopy=off.
> > > > > 
> > > > > The underlying fs is ext4.
> > > > > 
> > > > > zsj@debian:~/t$ mount|grep nvme
> > > > > /dev/nvme0n1p2 on / type ext4 (rw,relatime,errors=remount-ro)
> > > > > /dev/nvme0n1p4 on /home type ext4 (rw,relatime)
> > > > > /dev/nvme0n1p1 on /boot/efi type vfat 
> > > > > (rw,relatime,fmask=0077,dmask=0077,codepage=437,iocharset=ascii,shortname=mixed,utf8,errors=remount-ro)
> > > > > 
> > > > > I don't know how to test "create a white-out char dev node manually".
> > > > > 
> > > > > Thanks
> > > > 
> > > > thanks for re-validation.  I can reproduce the issue exactly on amd64 
> > > > system, but not on arm64.  It's really strange, also enabling dynamic 
> > > > debug output does not reveal anything useful.  I guess it would be good 
> > > > to dig into the related kernel code to get some deeper understanding, I 
> > > > hope to get start examining a bit in the upcoming weekend.
> > > 
> > > What is the current status for this issue? Can it be closesed or can
> > > you still reproduce it with recent kernels?
> > 
> > I can still reproduce this with 6.12.9 on amd64.  Sorry, I forgot about this
> > bug report.
> 
> Thanks for the confirmation.

I am sorry, I replied to fast w/o proper investigation.

Since v5.11 (commit 2d2f2d7322ff ("ovl: user xattr", 2020-12-14)), the
'userxattr' mount option is available and when it is used, it fixes the
reported issue.

Since v6.0 (commit b10b85fe5149 ("ovl: warn if trusted xattr creation
fails", 2022-07-27)), overlay warns about missing permissions on trusted
xattr and recommends to try mounting with 'userxattr' instead.

From my point of view, this bug can be closed. (Is it a 'fixed 5.11'
control statement?)

Thanks and kind regards,
Nicolas

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