[PATCH] util-linux: Add 'no-libmount-mountfd' PACKAGECONFIG option

[PATCH] util-linux: Add 'no-libmount-mountfd' PACKAGECONFIG option

[Niko Mauno]

The 2.39 version of util-linux took new file descriptors based mount
kernel API into use. In relation to this change, the upstream release
notes in
https://github.com/util-linux/util-linux/blob/v2.39/Documentation/releases/v2.39-ReleaseNotes#L14-L21
mention that

  This change is very aggressive to libmount code, but hopefully, it does not introduce regressions in traditional mount(8) behavior.

While testing with a board using a 6.1 version kernel, an initramfs
rootfs based boot flow contains the error

  [FAILED] Failed to start Remount Root and Kernel File Systems.
  See 'systemctl status systemd-remount-fs.service' for details.

on closer inspection:

  demoboard ~ # systemctl status -l systemd-remount-fs.service
  x systemd-remount-fs.service - Remount Root and Kernel File Systems
       Loaded: loaded (/usr/lib/systemd/system/systemd-remount-fs.service; enabled-runtime; preset: disabled)
       Active: failed (Result: exit-code) since Wed 2024-08-14 14:53:48 UTC; 1min 22s ago
         Docs: man:systemd-remount-fs.service(8)
               https://www.freedesktop.org/wiki/Software/systemd/APIFileSystems
      Process: 76 ExecStart=/usr/lib/systemd/systemd-remount-fs (code=exited, status=1/FAILURE)
     Main PID: 76 (code=exited, status=1/FAILURE)

  Aug 14 14:53:48 demoboard systemd-remount-fs[76]: /usr/bin/mount for / exited with exit status 32.
  Aug 14 14:53:48 demoboard systemd-remount-fs[81]: mount: /: mount point not mounted or bad option.
  Aug 14 14:53:48 demoboard systemd-remount-fs[81]:        dmesg(1) may have more information after failed mount system call.
  Aug 14 14:53:48 demoboard systemd[1]: systemd-remount-fs.service: Main process exited, code=exited, status=1/FAILURE
  Aug 14 14:53:48 demoboard systemd[1]: systemd-remount-fs.service: Failed with result 'exit-code'.
  Aug 14 14:53:48 demoboard systemd[1]: Failed to start Remount Root and Kernel File Systems.

also consequentially, 'systemctl status' reported:

  State: degraded

When issuing 'strace -ff mount -o remount /' the failure occurs at

  mount_setattr(3, "", AT_EMPTY_PATH, {attr_set=MOUNT_ATTR_RDONLY|MOUNT_ATTR_NOATIME|MOUNT_ATTR_NODIRATIME, attr_clr=MOUNT_ATTR_NOSUID|MOUNT_ATTR_NODEV|MOUNT_ATTR_NOEXEC|MOUNT_ATTR_NOATIME|MOUNT_ATTR_STRICTATIME|MOUNT_ATTR_NOSYMFOLLOW|0x40, propagation=0 /* MS_??? */, userns_fd=0}, 32) = -1 EINVAL (Invalid argument)

however the failure didn't occur when using qemuarm64 with 6.6 version
kernel to boot a corresponding initramfs image, in that case the exact
same call under strace returned 0.

Taking the above findings into consideration, add a new PACKAGECONFIG
option which allows to conveniently opt-out from prematurely using a
feature which can cause issues with a bit older kernels.

Signed-off-by: Niko Mauno <niko.mauno@vaisala.com>
---
 meta/recipes-core/util-linux/util-linux_2.40.1.bb | 1 +
 1 file changed, 1 insertion(+)

diff --git a/meta/recipes-core/util-linux/util-linux_2.40.1.bb b/meta/recipes-core/util-linux/util-linux_2.40.1.bb
index a1aab94055..3ecc55f61e 100644
--- a/meta/recipes-core/util-linux/util-linux_2.40.1.bb
+++ b/meta/recipes-core/util-linux/util-linux_2.40.1.bb
@@ -107,6 +107,7 @@ PACKAGECONFIG[cryptsetup] = "--with-cryptsetup,--without-cryptsetup,cryptsetup"
 PACKAGECONFIG[chfn-chsh] = "--enable-chfn-chsh,--disable-chfn-chsh,"
 PACKAGECONFIG[selinux] = "--with-selinux,--without-selinux,libselinux"
 PACKAGECONFIG[lastlog2] = "--enable-liblastlog2,--disable-liblastlog2,sqlite3"
+PACKAGECONFIG[no-libmount-mountfd] = "--disable-libmount-mountfd-support"
 
 EXTRA_OEMAKE = "ARCH=${TARGET_ARCH} CPU= CPUOPT= 'OPT=${CFLAGS}'"
 
-- 
2.39.2

Re: [OE-core] [PATCH] util-linux: Add 'no-libmount-mountfd' PACKAGECONFIG option

[Alexander Kanavin]

On Fri, 16 Aug 2024 at 16:04, Niko Mauno via lists.openembedded.org
<niko.mauno=vaisala.com@lists.openembedded.org> wrote:

> Taking the above findings into consideration, add a new PACKAGECONFIG
> option which allows to conveniently opt-out from prematurely using a
> feature which can cause issues with a bit older kernels.
> +PACKAGECONFIG[no-libmount-mountfd] = "--disable-libmount-mountfd-support"

The option's definition should include both enabling and disabling
options so that the resulting component configuration is deterministic
(e.g. not left to autodetection by upstream) both when it's enabled
and when it is not. It also helps to add a comment just above
explaining that only the newer kernels have the required API, and
ideally also mention which is the minimum required kernel version.

Alex

Re: [OE-core] [PATCH] util-linux: Add 'no-libmount-mountfd' PACKAGECONFIG option

[Niko Mauno]

On 16.8.2024 17.24, Alexander Kanavin wrote:
> On Fri, 16 Aug 2024 at 16:04, Niko Mauno via lists.openembedded.org
> <niko.mauno=vaisala.com@lists.openembedded.org> wrote:
> 
>> Taking the above findings into consideration, add a new PACKAGECONFIG
>> option which allows to conveniently opt-out from prematurely using a
>> feature which can cause issues with a bit older kernels.
>> +PACKAGECONFIG[no-libmount-mountfd] = "--disable-libmount-mountfd-support"
> 
> The option's definition should include both enabling and disabling
> options so that the resulting component configuration is deterministic
> (e.g. not left to autodetection by upstream) both when it's enabled
> and when it is not. It also helps to add a comment just above
> explaining that only the newer kernels have the required API, and
> ideally also mention which is the minimum required kernel version.

Thanks, submitted v2 which addresses aforementioned aspects, and also 
now defaults to disabling the new mount API by default.
-Niko

Re: [OE-core] [PATCH] util-linux: Add 'no-libmount-mountfd' PACKAGECONFIG option

[ChenQi]

I'm a little concerned about this patch because PACKAGECONFIG like this 
is likely to sit there forever.
The master branch's kernel version is at least 6.6. So this patch does 
not have any effect for master branch, right? If this PACKAGECONFIG is 
added, when should we remove it?
Also, if the automatic detection codes determine util-linux could build 
with mountfd support, but it fails at runtime, then it sounds like 
something to fix for the auto detection codes in 
configure.ac/meson.build. So if we really want to improve something, 
maybe we should work with the util-linux community to add more checks 
about mountfd. Maybe start by filing an issue for util-linux?

Regards,
Qi


On 8/16/24 22:04, Niko Mauno via lists.openembedded.org wrote:
> The 2.39 version of util-linux took new file descriptors based mount
> kernel API into use. In relation to this change, the upstream release
> notes in
> https://github.com/util-linux/util-linux/blob/v2.39/Documentation/releases/v2.39-ReleaseNotes#L14-L21
> mention that
>
>    This change is very aggressive to libmount code, but hopefully, it does not introduce regressions in traditional mount(8) behavior.
>
> While testing with a board using a 6.1 version kernel, an initramfs
> rootfs based boot flow contains the error
>
>    [FAILED] Failed to start Remount Root and Kernel File Systems.
>    See 'systemctl status systemd-remount-fs.service' for details.
>
> on closer inspection:
>
>    demoboard ~ # systemctl status -l systemd-remount-fs.service
>    x systemd-remount-fs.service - Remount Root and Kernel File Systems
>         Loaded: loaded (/usr/lib/systemd/system/systemd-remount-fs.service; enabled-runtime; preset: disabled)
>         Active: failed (Result: exit-code) since Wed 2024-08-14 14:53:48 UTC; 1min 22s ago
>           Docs: man:systemd-remount-fs.service(8)
>                 https://www.freedesktop.org/wiki/Software/systemd/APIFileSystems
>        Process: 76 ExecStart=/usr/lib/systemd/systemd-remount-fs (code=exited, status=1/FAILURE)
>       Main PID: 76 (code=exited, status=1/FAILURE)
>
>    Aug 14 14:53:48 demoboard systemd-remount-fs[76]: /usr/bin/mount for / exited with exit status 32.
>    Aug 14 14:53:48 demoboard systemd-remount-fs[81]: mount: /: mount point not mounted or bad option.
>    Aug 14 14:53:48 demoboard systemd-remount-fs[81]:        dmesg(1) may have more information after failed mount system call.
>    Aug 14 14:53:48 demoboard systemd[1]: systemd-remount-fs.service: Main process exited, code=exited, status=1/FAILURE
>    Aug 14 14:53:48 demoboard systemd[1]: systemd-remount-fs.service: Failed with result 'exit-code'.
>    Aug 14 14:53:48 demoboard systemd[1]: Failed to start Remount Root and Kernel File Systems.
>
> also consequentially, 'systemctl status' reported:
>
>    State: degraded
>
> When issuing 'strace -ff mount -o remount /' the failure occurs at
>
>    mount_setattr(3, "", AT_EMPTY_PATH, {attr_set=MOUNT_ATTR_RDONLY|MOUNT_ATTR_NOATIME|MOUNT_ATTR_NODIRATIME, attr_clr=MOUNT_ATTR_NOSUID|MOUNT_ATTR_NODEV|MOUNT_ATTR_NOEXEC|MOUNT_ATTR_NOATIME|MOUNT_ATTR_STRICTATIME|MOUNT_ATTR_NOSYMFOLLOW|0x40, propagation=0 /* MS_??? */, userns_fd=0}, 32) = -1 EINVAL (Invalid argument)
>
> however the failure didn't occur when using qemuarm64 with 6.6 version
> kernel to boot a corresponding initramfs image, in that case the exact
> same call under strace returned 0.
>
> Taking the above findings into consideration, add a new PACKAGECONFIG
> option which allows to conveniently opt-out from prematurely using a
> feature which can cause issues with a bit older kernels.
>
> Signed-off-by: Niko Mauno <niko.mauno@vaisala.com>
> ---
>   meta/recipes-core/util-linux/util-linux_2.40.1.bb | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/meta/recipes-core/util-linux/util-linux_2.40.1.bb b/meta/recipes-core/util-linux/util-linux_2.40.1.bb
> index a1aab94055..3ecc55f61e 100644
> --- a/meta/recipes-core/util-linux/util-linux_2.40.1.bb
> +++ b/meta/recipes-core/util-linux/util-linux_2.40.1.bb
> @@ -107,6 +107,7 @@ PACKAGECONFIG[cryptsetup] = "--with-cryptsetup,--without-cryptsetup,cryptsetup"
>   PACKAGECONFIG[chfn-chsh] = "--enable-chfn-chsh,--disable-chfn-chsh,"
>   PACKAGECONFIG[selinux] = "--with-selinux,--without-selinux,libselinux"
>   PACKAGECONFIG[lastlog2] = "--enable-liblastlog2,--disable-liblastlog2,sqlite3"
> +PACKAGECONFIG[no-libmount-mountfd] = "--disable-libmount-mountfd-support"
>   
>   EXTRA_OEMAKE = "ARCH=${TARGET_ARCH} CPU= CPUOPT= 'OPT=${CFLAGS}'"
>   
>
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