Re: [Bugme-new] [Bug 10737] New: pktgen procfs problem

On Sun, 18 May 2008 03:39:42 +0200 Patrick McHardy [off-list ref] wrote:

Andrew Morton wrote:

quoted

(switched to email.  Please respond via emailed reply-to-all, not via the
bugzilla web interface).

On Sat, 17 May 2008 13:59:25 -0700 (PDT) bugme-daemon@bugzilla.kernel.org wrote:

  

quoted

http://bugzilla.kernel.org/show_bug.cgi?id=10737

           Summary: pktgen procfs problem
           Product: Networking
           Version: 2.5
     KernelVersion: 2.6.26-rc2
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: Other
        AssignedTo: acme@ghostprotocols.net
        ReportedBy: devzero@web.de


Latest working kernel version: n/a
Earliest failing kernel version: 2.6.26-rc2
Distribution: suse 10.1
Hardware Environment: p4 + gigabyte i915g MoBo
Software Environment:
Problem Description:
pktgen module ocaasional seems to leak procfs entry

May 18 00:00:34 test kernel: [ 2663.373955] pktgen v2.69: Packet Generator for
packet performance testing.
May 18 00:00:34 test kernel: [ 2663.384819] remove_proc_entry: removing
non-empty directory 'net/pktgen', leaking at least 'kpktgend_1'
    

^^

Possibly we were always leaking this procfs entry, and newly-added
procfs diagnostics are now detecting it.
  

I've been looking into the same problem, without much success so
far. The problem appears to affect any /proc/net file, but not
files outside of /proc/net, so I'm guessing its net-ns related.
A testcase found by Ben Greear is opening the file multiple times:

# /tmp/open /proc/net/kpktgen_0

=> refcnt goes to 1

^C

=> refcnt goes to 0

Without ^C and opening the file a second time:

# /tmp/open /proc/net/kpktgen_0

=> refcnt goes to 2 (sometimes also 11)

^C

=> refcnt stays at previous value.

The refcnt even leaks if the file can't be successfully opened,
for example because of lacking permissions.

urgh.  Is any of this known to be post-2.6.25?