79 lines
2.8 KiB
Diff
79 lines
2.8 KiB
Diff
From 7046c0424a0c521169f258ab02d90739dade6269 Mon Sep 17 00:00:00 2001
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From: Andrey Ulanov <aulanov@gmail.com>
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Date: Mon, 12 Dec 2016 17:38:18 -0800
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Subject: [PATCH] nspawn: when getting SIGCHLD make sure it's from the first
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child (#4855)
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When getting SIGCHLD we should not assume that it was the first
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child forked from system-nspawn that has died as it may also be coming
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from an orphan process. This change adds a signal handler that ignores
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SIGCHLD unless it came from the first containerized child - the real
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child.
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Before this change the problem can be reproduced as follows:
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$ sudo systemd-nspawn --directory=/container-root --share-system
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Press ^] three times within 1s to kill container.
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[root@andreyu-coreos ~]# { true & } &
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[1] 22201
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[root@andreyu-coreos ~]#
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Container root-fedora-latest terminated by signal KILL
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(cherry picked from commit 6916b164642d8bb4938878f4284f8ee5ccf3efd6)
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---
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src/nspawn/nspawn.c | 25 +++++++++++++++++++++++--
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1 file changed, 23 insertions(+), 2 deletions(-)
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diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
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index 81573be95a..503265545b 100644
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--- a/src/nspawn/nspawn.c
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+++ b/src/nspawn/nspawn.c
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@@ -38,6 +38,7 @@
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#include <sys/personality.h>
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#include <sys/prctl.h>
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#include <sys/types.h>
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+#include <sys/wait.h>
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#include <unistd.h>
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#include "sd-daemon.h"
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@@ -2538,6 +2539,26 @@ static int on_orderly_shutdown(sd_event_source *s, const struct signalfd_siginfo
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return 0;
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}
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+static int on_sigchld(sd_event_source *s, const struct signalfd_siginfo *ssi, void *userdata) {
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+ for (;;) {
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+ siginfo_t si = {};
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+ if (waitid(P_ALL, 0, &si, WNOHANG|WNOWAIT|WEXITED) < 0)
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+ return log_error_errno(errno, "Failed to waitid(): %m");
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+ if (si.si_pid == 0) /* No pending children. */
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+ break;
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+ if (si.si_pid == PTR_TO_PID(userdata)) {
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+ /* The main process we care for has exited. Return from
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+ * signal handler but leave the zombie. */
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+ sd_event_exit(sd_event_source_get_event(s), 0);
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+ break;
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+ }
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+ /* Reap all other children. */
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+ (void) waitid(P_PID, si.si_pid, &si, WNOHANG|WEXITED);
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+ }
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+
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+ return 0;
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+}
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+
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static int determine_names(void) {
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int r;
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@@ -3952,8 +3973,8 @@ static int run(int master,
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sd_event_add_signal(event, NULL, SIGTERM, NULL, NULL);
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}
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- /* simply exit on sigchld */
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- sd_event_add_signal(event, NULL, SIGCHLD, NULL, NULL);
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+ /* Exit when the child exits */
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+ sd_event_add_signal(event, NULL, SIGCHLD, on_sigchld, PID_TO_PTR(*pid));
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if (arg_expose_ports) {
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r = expose_port_watch_rtnl(event, rtnl_socket_pair[0], on_address_change, exposed, &rtnl);
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--
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2.9.3
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