[LTP] [PATCH] pidfs: return -EREMOTE when PIDFD_GET_INFO is called on another ns

[Christian Brauner]

On Fri, Feb 06, 2026 at 10:51:24AM +0800, kernel test robot wrote:
> 
> 
> Hello,
> 
> kernel test robot noticed "ltp.ioctl_pidfd06.fail" on:
> 
> commit: 16cc0cf19e0b75a336cbf619d208e22b351bd430 ("[PATCH] pidfs: return -EREMOTE when PIDFD_GET_INFO is called on another ns")
> url: https://github.com/intel-lab-lkp/linux/commits/luca-boccassi-gmail-com/pidfs-return-EREMOTE-when-PIDFD_GET_INFO-is-called-on-another-ns/20260128-065425
> base: https://git.kernel.org/cgit/linux/kernel/git/vfs/vfs.git vfs.all
> patch link: https://lore.kernel.org/all/20260127225209.2293342-1-luca.boccassi@gmail.com/
> patch subject: [PATCH] pidfs: return -EREMOTE when PIDFD_GET_INFO is called on another ns
> 
> in testcase: ltp
> version: 
> with following parameters:
> 
> 	disk: 1SSD
> 	fs: btrfs
> 	test: syscalls-00/ioctl_pidfd06
> 
> 
> 
> config: x86_64-rhel-9.4-ltp
> compiler: gcc-14
> test machine: 4 threads 1 sockets Intel(R) Core(TM) i3-3220 CPU @ 3.30GHz (Ivy Bridge) with 8G memory
> 
> (please refer to attached dmesg/kmsg for entire log/backtrace)
> 
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <oliver.sang@intel.com>
> | Closes: https://lore.kernel.org/oe-lkp/202602061056.b94e9170-lkp@intel.com
> 
> 
> 2026-02-03 16:33:15 kirk -U ltp -f temp_single_test --env TMPDIR=/fs/sdb1/tmpdir
> Host information
> 
> 	Hostname:   lkp-ivb-d04
> 	Python:     3.13.5 (main, Jun 25 2025, 18:55:22) [GCC 14.2.0]
> 	Directory:  /tmp/kirk.root/tmppqdrj0by
> 
> Connecting to SUT: default
> 
> Starting suite: temp_single_test
> ---------------------------------
> ioctl_pidfd06: fail | tainted  (0.034s)
>                                                                                                                                 
> Execution time: 0.100s
> 
> 	Suite:       temp_single_test
> 	Total runs:  1
> 	Runtime:     0.034s
> 	Passed:      0
> 	Failed:      1
> 	Skipped:     0
> 	Broken:      0
> 	Warnings:    0
> 	Kernel:      Linux 6.19.0-rc5-00159-g16cc0cf19e0b #1 SMP PREEMPT_DYNAMIC Tue Feb  3 23:56:34 CST 2026
> 	Machine:     unknown
> 	Arch:        x86_64
> 	RAM:         6899592 kB
> 	Swap:        0 kB
> 	Distro:      debian 13
> 
> Disconnecting from SUT: default
> Session stopped

Thanks! This is an intentional change in behavior and only affects
systemd which is happy to adapt to that change.