Date: Mon, 15 Nov 2010 09:53:57 -0800 From: Garrett Cooper <yanegomi@gmail.com> To: freebsd-hackers@freebsd.org Subject: Phantom sysctl Message-ID: <AANLkTik0CgFYKfaGKGktKtUjotfRFjKPOPPbecMRpWDS@mail.gmail.com>
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According to SYSCTL_INT(9):
The SYSCTL kernel interfaces allow code to statically declare sysctl(8)
MIB entries, which will be initialized when the kernel module containing
the declaration is initialized. When the module is unloaded, the sysctl
will be automatically destroyed.
The sysctl should be reaped when the module is unloaded. My dumb
test kernel module [1] doesn't seem to do that though (please note
that the OID test_int_sysctl is created, and not reaped... FWIW it's
kind of bizarre that test_int_sysctl is created in the first place,
given what I've seen when SYSCTL_* gets executed):
toaster# kldload ./test_int_sysctl.ko
toaster# sysctl -a | grep test
test_int_sysctl: 0
vfs.nfs_common.realign_test: 0
debug.test_int_sysctl: 0
toaster# sysctl test_int_sysctl
sysctl: unknown oid 'test_int_sysctl'
toaster# kldunload ./test_int_sysctl.ko
toaster# sysctl -a | grep test
test_int_sysctl: 0
vfs.nfs_common.realign_test: 0
toaster# sysctl test_int_sysctl
sysctl: unknown oid 'test_int_sysctl'
I've seen this behavior on 8.1-RELEASE (custom kernel, vanilla
sources), and CURRENT r215254.
I'm compiling the kernel with SYSCTL_DEBUG (and added some missing
error checking in the kern_sysctl.c code) to see if I can track down
the resource issue, but in the meantime if someone more knowledgeable
has some suggestions for what to do / where I should look, I'm all
ears.
Thanks!
-Garrett
1. http://pastebin.com/n7d9bH8U
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