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Groups > linux.debian.kernel > #85802 > unrolled thread
| Started by | Salvatore Bonaccorso <carnil@debian.org> |
|---|---|
| First post | 2025-02-20 13:30 +0100 |
| Last post | 2025-02-21 11:20 +0100 |
| Articles | 5 — 4 participants |
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Bug#969223: Can't rm directory on overlayfs in userns Salvatore Bonaccorso <carnil@debian.org> - 2025-02-20 13:30 +0100
Bug#969223: Can't rm directory on overlayfs in userns Nicolas Schier <nicolas@fjasle.eu> - 2025-02-20 15:10 +0100
Bug#969223: Can't rm directory on overlayfs in userns Salvatore Bonaccorso <carnil@debian.org> - 2025-02-20 16:50 +0100
Bug#969223: Can't rm directory on overlayfs in userns Nicolas Schier <n.schier@avm.de> - 2025-02-21 11:20 +0100
Processed: Re: Bug#969223: Can't rm directory on overlayfs in userns "Debian Bug Tracking System" <owner@bugs.debian.org> - 2025-02-21 11:20 +0100
| From | Salvatore Bonaccorso <carnil@debian.org> |
|---|---|
| Date | 2025-02-20 13:30 +0100 |
| Subject | Bug#969223: Can't rm directory on overlayfs in userns |
| Message-ID | <KidQM-BJ6-77@gated-at.bofh.it> |
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 <nicolas@fjasle.eu> wrote: > > > > > > [2]: https://lore.kernel.org/linux-unionfs/CAJfpegsiuf8ib5cvVrr=zHZ+Xu7BMMTT2eYapsEUdmPcRBUiwQ@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? Regards, Salvatore
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| From | Nicolas Schier <nicolas@fjasle.eu> |
|---|---|
| Date | 2025-02-20 15:10 +0100 |
| Message-ID | <Kifpv-CPk-15@gated-at.bofh.it> |
| In reply to | #85802 |
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 <nicolas@fjasle.eu> wrote: > > > > > > > [2]: https://lore.kernel.org/linux-unionfs/CAJfpegsiuf8ib5cvVrr=zHZ+Xu7BMMTT2eYapsEUdmPcRBUiwQ@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. Kind regards, Nicolas
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| From | Salvatore Bonaccorso <carnil@debian.org> |
|---|---|
| Date | 2025-02-20 16:50 +0100 |
| Message-ID | <KigYh-DI3-3@gated-at.bofh.it> |
| In reply to | #85880 |
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 <nicolas@fjasle.eu> wrote: > > > > > > > > [2]: https://lore.kernel.org/linux-unionfs/CAJfpegsiuf8ib5cvVrr=zHZ+Xu7BMMTT2eYapsEUdmPcRBUiwQ@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. Regards, Salvatore
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| From | Nicolas Schier <n.schier@avm.de> |
|---|---|
| Date | 2025-02-21 11:20 +0100 |
| Message-ID | <Kiyit-OI9-7@gated-at.bofh.it> |
| In reply to | #85963 |
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 <nicolas@fjasle.eu> wrote:
> > > > > > > > > [2]: https://lore.kernel.org/linux-unionfs/CAJfpegsiuf8ib5cvVrr=zHZ+Xu7BMMTT2eYapsEUdmPcRBUiwQ@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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| From | "Debian Bug Tracking System" <owner@bugs.debian.org> |
|---|---|
| Date | 2025-02-21 11:20 +0100 |
| Subject | Processed: Re: Bug#969223: Can't rm directory on overlayfs in userns |
| Message-ID | <Kiyit-OI9-9@gated-at.bofh.it> |
| In reply to | #86011 |
Processing commands for control@bugs.debian.org: > notfound 969223 6.12.9-1 Bug #969223 [src:linux] Can't rm directory on overlayfs in userns No longer marked as found in versions linux/6.12.9-1. > thanks Stopping processing here. Please contact me if you need assistance. -- 969223: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=969223 Debian Bug Tracking System Contact owner@bugs.debian.org with problems
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