[pve-devel] [PATCH common] procfstools: use absolute path when reading PSI from sysfs

[pve-devel] [PATCH common] procfstools: use absolute path when reading PSI from sysfs

[Lukas Wagner]

With the newly introduced PSI parsing from sysfs, a `qm list` reported
uninitialized values.

$ qm list
Use of uninitialized value in multiplication (*) at /usr/share/perl5/PVE/QemuServer.pm line 2716.
Use of uninitialized value in multiplication (*) at /usr/share/perl5/PVE/QemuServer.pm line 2717.
Use of uninitialized value in multiplication (*) at /usr/share/perl5/PVE/QemuServer.pm line 2718.
Use of uninitialized value in multiplication (*) at /usr/share/perl5/PVE/QemuServer.pm line 2719.
Use of uninitialized value in multiplication (*) at /usr/share/perl5/PVE/QemuServer.pm line 2720.
....

Digging into the source code of qemu-server showed that the call to
read_cgroup_pressure returned undef. The cause was a missing /-prefix
for the sysfs path, which made it a relative path instead of an absolute
path. For pvestatd this was fine, since this daemon uses `/` as a
working directory.

Reported-by: Hannes Dürr <h.duerr@proxmox.com>
Signed-off-by: Lukas Wagner <l.wagner@proxmox.com>
---
 src/PVE/ProcFSTools.pm | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/PVE/ProcFSTools.pm b/src/PVE/ProcFSTools.pm
index f28372b..9bfac2c 100644
--- a/src/PVE/ProcFSTools.pm
+++ b/src/PVE/ProcFSTools.pm
@@ -156,7 +156,7 @@ sub read_cgroup_pressure {
 
     my $res = {};
     for my $type (qw(cpu memory io)) {
-        my $stats = parse_pressure("sys/fs/cgroup/${cgroup_path}/${type}.pressure");
+        my $stats = parse_pressure("/sys/fs/cgroup/${cgroup_path}/${type}.pressure");
         $res->{$type} = $stats if $stats;
     }
     return $res;
-- 
2.47.2



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[pve-devel] applied: [PATCH common] procfstools: use absolute path when reading PSI from sysfs

[Thomas Lamprecht]

On Thu, 31 Jul 2025 11:58:04 +0200, Lukas Wagner wrote:
> With the newly introduced PSI parsing from sysfs, a `qm list` reported
> uninitialized values.
> 
> $ qm list
> Use of uninitialized value in multiplication (*) at /usr/share/perl5/PVE/QemuServer.pm line 2716.
> Use of uninitialized value in multiplication (*) at /usr/share/perl5/PVE/QemuServer.pm line 2717.
> Use of uninitialized value in multiplication (*) at /usr/share/perl5/PVE/QemuServer.pm line 2718.
> Use of uninitialized value in multiplication (*) at /usr/share/perl5/PVE/QemuServer.pm line 2719.
> Use of uninitialized value in multiplication (*) at /usr/share/perl5/PVE/QemuServer.pm line 2720.
> ....
> 
> [...]

Applied, thanks!

[1/1] procfstools: use absolute path when reading PSI from sysfs
      commit: 006048552e3b48412c8c50e51bb1e1f6d5665859


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