On 19.08.24 10:41, Christian Brauner wrote:
> On Sat, Aug 17, 2024 at 08:58:18PM GMT, Eric Biggers wrote:
>> On Wed, Jul 31, 2024 at 12:01:12PM +0200, Christian Brauner wrote:
>>> It's currently possible to create pidfds for kthreads but it is unclear
>>> what that is supposed to mean. Until we have use-cases for it and we
>>> figured out what behavior we want block the creation of pidfds for
>>> kthreads.
>>>
>>> Fixes: 32fcb426ec00 ("pid: add pidfd_open()")
>>> Cc: stable@xxxxxxxxxxxxxxx
>>> Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
>>> ---
>>> kernel/fork.c | 25 ++++++++++++++++++++++---
>>> 1 file changed, 22 insertions(+), 3 deletions(-)
>>
>> Unfortunately this commit broke systemd-shutdown's ability to kill processes,
>> which makes some filesystems no longer get unmounted at shutdown.
>>
>> It looks like systemd-shutdown relies on being able to create a pidfd for any
>> process listed in /proc (even a kthread), and if it gets EINVAL it treats it a
>> fatal error and stops looking for more processes...
>
> Thanks for the report!
> I talked to Daan De Meyer who made that change and he said that this
> must a systemd version that hasn't gotten his fixes yet. In any case, if
> this causes regression then I'll revert it right now. See the appended
> revert.
Greg, Sasha, JFYI in case you are not already aware of it: I by
chance[1] noticed that the patch Christian plans to revert is still in
the 6.10-queue. You might want to drop it (or apply the revert as well,
which is in -next, but not yet in mainline afaics).
Ciao, Thorsten
[1] after I noticed this thread a third time, this time via some SELinux
problems it caused in Fedora land:
https://bugzilla.redhat.com/show_bug.cgi?id=2306818
https://bugzilla.redhat.com/show_bug.cgi?id=2305270
