On Tue, Feb 04, 2025 at 01:26:13PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@xxxxxxxxxx>
>
> As mentioned in the previous patch, trying to isolate processes from
> separate test instances through the use of distinct Unix process
> sessions is annoying due to the many complications with signal handling.
>
> Instead, we could just use nsexec to run the test program with a private
> pid namespace so that each test instance can only see its own processes;
> and private mount namespace so that tests writing to /tmp cannot clobber
> other tests or the stuff running on the main system.
>
> However, it's not guaranteed that a particular kernel has pid and mount
> namespaces enabled. Mount (2.4.19) and pid (2.6.24) namespaces have
> been around for a long time, but there's no hard requirement for the
> latter to be enabled in the kernel. Therefore, this bugfix slips
> namespace support in alongside the session id thing.
>
> Declaring CONFIG_PID_NS=n a deprecated configuration and removing
> support should be a separate conversation, not something that I have to
> do in a bug fix to get mainline QA back up.
>
> Cc: <fstests@xxxxxxxxxxxxxxx> # v2024.12.08
> Fixes: 8973af00ec212f ("fstests: cleanup fsstress process management")
> Signed-off-by: "Darrick J. Wong" <djwong@xxxxxxxxxx>
> ---
> check | 34 +++++++++++++++++++++++-----------
> common/rc | 12 ++++++++++--
> src/nsexec.c | 18 +++++++++++++++---
> tests/generic/504 | 15 +++++++++++++--
> tools/run_seq_pidns | 28 ++++++++++++++++++++++++++++
> 5 files changed, 89 insertions(+), 18 deletions(-)
> create mode 100755 tools/run_seq_pidns
Same question as for session ids - is this all really necessary (or
desired) if check-parallel executes check in it's own private PID
namespace?
If so, then the code is fine apart from the same nit about
tools/run_seq_pidns - call it run_pidns because this helper will
also be used by check-parallel to run check in it's own private
mount and PID namespaces...
> diff --git a/tests/generic/504 b/tests/generic/504
> index 271c040e7b842a..96f18a0bbc7ba2 100755
> --- a/tests/generic/504
> +++ b/tests/generic/504
> @@ -18,7 +18,7 @@ _cleanup()
> {
> exec {test_fd}<&-
> cd /
> - rm -f $tmp.*
> + rm -r -f $tmp.*
> }
>
> # Import common functions.
> @@ -35,13 +35,24 @@ echo inode $tf_inode >> $seqres.full
>
> # Create new fd by exec
> exec {test_fd}> $testfile
> -# flock locks the fd then exits, we should see the lock info even the owner is dead
> +# flock locks the fd then exits, we should see the lock info even the owner is
> +# dead. If we're using pid namespace isolation we have to move /proc so that
> +# we can access the /proc/locks from the init_pid_ns.
> +if [ "$FSTESTS_ISOL" = "privatens" ]; then
> + move_proc="$tmp.procdir"
> + mkdir -p "$move_proc"
> + mount --move /proc "$move_proc"
> +fi
> flock -x $test_fd
> cat /proc/locks >> $seqres.full
>
> # Checking
> grep -q ":$tf_inode " /proc/locks || echo "lock info not found"
>
> +if [ -n "$move_proc" ]; then
> + mount --move "$move_proc" /proc
> +fi
> +
> # success, all done
> status=0
> echo "Silence is golden"
Urk. That explains the failure I've noticed but not had time to
debug from check-parallel when using a private pidns. Do you know
why /proc/locks in the overlaid mount does not show the locks taken
from within that namespace? Is that a bug in the namespace/lock
code?
Regardless, the code looks ok so with the helper renamed:
Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx>
--
Dave Chinner
david@xxxxxxxxxxxxx
