Hello there,
I am creating a sysctl kernel module to register 2 hierarchy under same
proc name. For e.g.
my_net
| |
net1 net2
| |
t1 t2
So, I used register_sysctl_paths() API for registering the sysctl tables
net1 net2 under path name my_net.
Problem is when unregistering the tables dmesg shows a warning and call
trace.
# rmmod sysctl.ko
# dmesg
------------[ cut here ]------------
WARNING: at kernel/sysctl.c:2270 unregister_sysctl_table+0xb1/0x120()
(Tainted: P W ---------------- )
Hardware name: VMware Virtual Platform
Modules linked in: sysctl(-)(U) ip6table_filter ip6_tables ebtable_nat
ebtables xt_CHECKSUM iptable_mangle ipt_MASQUERADE iptable_nat nf_nat
nf_conntrack_ipv4 nf_defrag_ipv4 xt_state nf_conntrack ipt_REJECT bridge
autofs4 sunrpc fcoe libfcoe libfc scsi_transport_fc scsi_tgt 8021q garp stp
llc cachefiles fscache ipv6 xt_physdev iptable_filter ip_tables dm_mirror
dm_region_hash dm_log uinput ppdev parport_pc parport e1000 pcnet32 mii
vmware_balloon sg i2c_piix4 i2c_core shpchp ext4 mbcache jbd2 vxspec(P)(U)
vxio(P)(U) vxdmp(P)(U) sd_mod crc_t10dif sr_mod cdrom mptspi mptscsih
mptbase scsi_transport_spi ata_generic pata_acpi ata_piix dm_mod [last
unloaded: sysctl]
Pid: 22463, comm: rmmod Tainted: P W ----------------
2.6.32-71.el6.x86_64 #1
Call Trace:
[<ffffffff8106b857>] warn_slowpath_common+0x87/0xc0
[<ffffffff8106b8aa>] warn_slowpath_null+0x1a/0x20
[<ffffffff81076251>] unregister_sysctl_table+0xb1/0x120
[<ffffffff810c611c>] ? stop_machine_destroy+0x4c/0x50
[<ffffffff810c621b>] ? stop_machine+0x4b/0x60
[<ffffffffa002d021>] sysctl_module_exit+0x21/0x23 [sysctl]
[<ffffffff810ac706>] sys_delete_module+0x1a6/0x280
[<ffffffff8101ea88>] ? syscall_trace_enter+0x1d8/0x1e0
[<ffffffff81013387>] tracesys+0xd9/0xde
---[ end trace fee2c1c8e41aeb36 ]---
Kindly, help me to resolve this warning.
Following is module.
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sysctl.h>
static struct ctl_table_header * test_sysctl_header1;
static struct ctl_table_header * test_sysctl_header2;
int value1 = 0;
int value2 = 1;
int min = 10;
int max = 20;
static ctl_table test_table1[] = {
{
.ctl_name = CTL_UNNUMBERED,
.procname = "value1",
.data = &value1,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler
= &proc_dointvec_minmax,
.strategy =
&sysctl_intvec,
.extra1 = &min,
.extra2 = &max
},
{
.ctl_name = CTL_UNNUMBERED,
.procname = "value2",
.data = &value2,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler
= &proc_dointvec_minmax,
.strategy =
&sysctl_intvec,
.extra1 = &min,
.extra2 = &max
},
{ .ctl_name = 0 }
};
static ctl_table test_table2[] = {
{
.ctl_name = CTL_UNNUMBERED,
.procname = "value1",
.data = &value1,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler
= &proc_dointvec_minmax,
.strategy =
&sysctl_intvec,
.extra1 = &min,
.extra2 = &max
},
{
.ctl_name = CTL_UNNUMBERED,
.procname = "value2",
.data = &value2,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler
= &proc_dointvec_minmax,
.strategy =
&sysctl_intvec,
.extra1 = &min,
.extra2 = &max
},
{ .ctl_name = 0 }
};
static ctl_table test_net_table1[] = {
{
.ctl_name = CTL_UNNUMBERED,
.procname = "test1",
.mode = 0555,
.child = test_table1
},
{ .ctl_name = 0 }
};
static ctl_table test_net_table2[] = {
{
.ctl_name = CTL_UNNUMBERED,
.procname = "test2",
.mode = 0555,
.child = test_table2
},
{ .ctl_name = 0 }
};
static ctl_table test_root_table1[] = {
{
.ctl_name = CTL_UNNUMBERED,
.procname = "net1",
.mode = 0555,
.child = test_net_table1
},
{ .ctl_name = 0 }
};
static ctl_table test_root_table2[] = {
{
.ctl_name = CTL_UNNUMBERED,
.procname = "net2",
.mode = 0555,
.child = test_net_table2
},
{ .ctl_name = 0 }
};
static struct ctl_path net1_path[] = {
{ .procname = "my_net", .ctl_name = CTL_UNNUMBERED },
{ }
};
static int __init sysctl_module_init(void)
{
test_sysctl_header1 =
register_sysctl_paths(net1_path, test_root_table1);
test_sysctl_header2 =
register_sysctl_paths(net1_path, test_root_table2);
return 0;
}
static void __exit sysctl_module_exit(void)
{
unregister_sysctl_table(test_sysctl_header1);
unregister_sysctl_table(test_sysctl_header2);
}
module_init(sysctl_module_init);
module_exit(sysctl_module_exit);
MODULE_LICENSE("GPL");
Thanks,
Chaitanya
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