From d0b587533ca9e450aaa3ab2de5c6f53e16414ad5 Mon Sep 17 00:00:00 2001 From: Fiona Ebner Date: Mon, 10 Jul 2023 10:52:59 +0200 Subject: [PATCH] qmeventd: improve getting VMID from PID in presence of legacy cgroup entries On a hybrid cgroup system, the /proc//cgroup file looks like > 13:pids:/qemu.slice/110.scope > 12:perf_event:/ > 11:devices:/qemu.slice > 10:misc:/ > 9:hugetlb:/ > 8:freezer:/ > 7:cpu,cpuacct:/qemu.slice/110.scope > 6:memory:/qemu.slice/110.scope > 5:rdma:/ > 4:cpuset:/ > 3:blkio:/qemu.slice > 2:net_cls,net_prio:/ > 1:name=systemd:/qemu.slice/110.scope > 0::/qemu.slice/110.scope but the order doesn't seem to be deterministic, so it can happen that an entry like '11:devices:/qemu.slice' is the first to match the '/qemu.slice' part, which previously made the code expect to find the VMID. To improve detection, as a first step, match the trailing slash too. Reported in the community forum: https://forum.proxmox.com/threads/129320/post-571654 Signed-off-by: Fiona Ebner --- qmeventd/qmeventd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/qmeventd/qmeventd.c b/qmeventd/qmeventd.c index 921c0dca..503bce69 100644 --- a/qmeventd/qmeventd.c +++ b/qmeventd/qmeventd.c @@ -109,7 +109,7 @@ get_vmid_from_pid(pid_t pid) } cgroup_path++; - if (strncmp(cgroup_path, "/qemu.slice", 11)) { + if (strncmp(cgroup_path, "/qemu.slice/", 12)) { continue; } @@ -142,7 +142,7 @@ get_vmid_from_pid(pid_t pid) if (errno) { fprintf(stderr, "error parsing vmid for %d: %s\n", pid, strerror(errno)); } else { - fprintf(stderr, "error parsing vmid for %d: no qemu.slice cgroup entry\n", pid); + fprintf(stderr, "error parsing vmid for %d: no matching qemu.slice cgroup entry\n", pid); } ret: