[pve-devel] [PATCH qemu-server] qmeventd: explicitly close() pidfds

[pve-devel] [PATCH qemu-server] qmeventd: explicitly close() pidfds

[Stefan Reiter]

In most circumstances a pidfd gets closed automatically once the child
dies, and that *should* be guaranteed by us calling SIGKILL - however,
it seems that sometimes that doesn't happen, leading to leaked file
descriptors[0].

Also add a small note to verbose mode showing when the late-cleanup
actually happens, helped during debug.

[0] https://forum.proxmox.com/threads/cannot-shutdown-vm.83911/

Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
---

I'm puzzled by this, and I'm not entirely sure this is the full fix, but it does
seem like a good idea to close the fds explicitly anyway.

 qmeventd/qmeventd.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/qmeventd/qmeventd.c b/qmeventd/qmeventd.c
index 57f1867..a14c331 100644
--- a/qmeventd/qmeventd.c
+++ b/qmeventd/qmeventd.c
@@ -600,6 +600,7 @@ sigkill(void *ptr, __attribute__((unused)) void *unused)
 
     if (data.pidfd > 0) {
 	err = pidfd_send_signal(data.pidfd, SIGKILL, NULL, 0);
+	(void)close(data.pidfd);
     } else {
 	err = kill(data.pid, SIGKILL);
     }
@@ -619,6 +620,7 @@ static void
 handle_forced_cleanup()
 {
     if (alarm_triggered) {
+	VERBOSE_PRINT("clearing forced cleanup backlog\n");
 	alarm_triggered = 0;
 	g_slist_foreach(forced_cleanups, sigkill, NULL);
 	g_slist_free_full(forced_cleanups, free);
-- 
2.20.1

[pve-devel] applied: [PATCH qemu-server] qmeventd: explicitly close() pidfds

[Thomas Lamprecht]

On 09.02.21 16:24, Stefan Reiter wrote:
> In most circumstances a pidfd gets closed automatically once the child
> dies, and that *should* be guaranteed by us calling SIGKILL - however,
> it seems that sometimes that doesn't happen, leading to leaked file
> descriptors[0].
> 
> Also add a small note to verbose mode showing when the late-cleanup
> actually happens, helped during debug.
> 
> [0] https://forum.proxmox.com/threads/cannot-shutdown-vm.83911/
> 
> Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
> ---
> 
> I'm puzzled by this, and I'm not entirely sure this is the full fix, but it does
> seem like a good idea to close the fds explicitly anyway.
> 
>  qmeventd/qmeventd.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
>

applied, thanks!