The POSIX-mandated behaviour of sending SIGCONT/SIGHUP to stopped processes
of an orphaned process group is not observed inside PID namespaces, as
can be verified by running [1] inside a PID namespace, for example.
The derivation is (presumably) introduced by Linux commit
v2.6.24-rc1~237 ("pid namespaces: define is_global_init() and
is_container_init()").
[1] https://gitlab.com/strace/strace/commit/4278e6613f48273e7da0989712f1c18aaffefd84
Reported-by: Dmitry V. Levin <ldv@xxxxxxxxxxxx>
Signed-off-by: Eugene Syromyatnikov <evgsyr@xxxxxxxxx>
---
man2/setpgid.2 | 1 +
man3/exit.3 | 3 ++-
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/man2/setpgid.2 b/man2/setpgid.2
index be451e7..492fbea 100644
--- a/man2/setpgid.2
+++ b/man2/setpgid.2
@@ -324,6 +324,7 @@ signal followed by a
.B SIGCONT
signal will be sent to each process
in the newly orphaned process group.
+This behaviour is not present inside PID namespaces on Linux.
.\" exit.3 refers to the following text:
An orphaned process group is one in which the parent of
every member of process group is either itself also a member
diff --git a/man3/exit.3 b/man3/exit.3
index 4a30fc3..5aef625 100644
--- a/man3/exit.3
+++ b/man3/exit.3
@@ -191,7 +191,8 @@ then a
signal followed by a
.B SIGCONT
signal will be
-sent to each process in this process group.
+sent to each process in this process group
+(except for the case the processes are in a PID namespace on Linux).
See
.BR setpgid (2)
for an explanation of orphaned process groups.
--
2.1.4
