From: Konstantin Khorenko khorenko@virtuozzo.com
[ Upstream commit 826d7bc9f013d01e92997883d2fd0c25f4af1f1c ]
If the flock owner process is dead and its pid has been already freed, pid translation won't work, but we still want to show flock owner pid number when expecting /proc/$PID/fdinfo/$FD in init pidns.
Reproducer: process A process A1 process A2 fork()---------> exit() open() flock() fork()---------> exit() sleep()
Before the patch: ================ (root@vz7)/: cat /proc/${PID_A2}/fdinfo/3 pos: 4 flags: 02100002 mnt_id: 257 lock: (root@vz7)/:
After the patch: =============== (root@vz7)/:cat /proc/${PID_A2}/fdinfo/3 pos: 4 flags: 02100002 mnt_id: 295 lock: 1: FLOCK ADVISORY WRITE ${PID_A1} b6:f8a61:529946 0 EOF
Fixes: 9d5b86ac13c5 ("fs/locks: Remove fl_nspid and use fs-specific l_pid for remote locks") Signed-off-by: Konstantin Khorenko khorenko@virtuozzo.com Acked-by: Andrey Vagin avagin@openvz.org Reviewed-by: Benjamin Coddington bcodding@redhat.com Signed-off-by: Jeff Layton jlayton@redhat.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- fs/locks.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/fs/locks.c b/fs/locks.c index db7b6917d9c5..fafce5a8d74f 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -2072,6 +2072,13 @@ static pid_t locks_translate_pid(struct file_lock *fl, struct pid_namespace *ns) return -1; if (IS_REMOTELCK(fl)) return fl->fl_pid; + /* + * If the flock owner process is dead and its pid has been already + * freed, the translation below won't work, but we still want to show + * flock owner pid number in init pidns. + */ + if (ns == &init_pid_ns) + return (pid_t)fl->fl_pid;
rcu_read_lock(); pid = find_pid_ns(fl->fl_pid, &init_pid_ns);