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Bug #6156
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Spurious "Unable to set CLSET_NODELAYONERR"
Start date:
2015-08-22
Due date:
% Done:
0%
Estimated time:
Difficulty:
Bite-size
Tags:
needs-triage
Gerrit CR:
Description
In spite of #4463's fix, I still occasionally see errors mentioned above. I have one theory, as extra-commented in refresh_nlm_rpc():
138 ret = clnt_tli_kcreate(&hostp->nh_knc, &hostp->nh_addr,
139 NLM_PROG, rpcp->nr_vers, 0, NLM_RPC_RETRIES,
140 CRED(), &rpcp->nr_handle);
141
142 /*
143 * Set the client's CLSET_NODELAYONERR option to true. The
144 * RPC clnt_call interface creates an artificial delay for
145 * certain call errors in order to prevent RPC consumers
146 * from getting into tight retry loops. Since this function is
147 * called by the NLM service routines we would like to avoid
148 * this artificial delay when possible. We do not retry if the
149 * NULL request fails so it is safe for us to turn this option
150 * on.
151 */
/* XXX KEBE ASKS what if ret is not zero? */
152 if (clnt_control(rpcp->nr_handle, CLSET_NODELAYONERR,
153 (char *)&clset) == FALSE) {
154 NLM_ERR("Unable to set CLSET_NODELAYONERR\n");
Reading further, we should kernel panic if ret is not zero, bcause rpcp->nr_handle would still be NULL. So that in and of itself is a problem too.
Regardless, I'm still seeing this, so either I'm incredibly lucky about clnt_control()'s side-effects, or for some other reason. I'm running dtrace to catch one. Maybe just the return-check alone is worth a fix...
Related issues
Updated by Dan McDonald about 6 years ago
I ran this dtrace script:
#!/usr/sbin/dtrace -Cs
refresh_nlm_rpc:entry
/((nlm_rpc_t *)arg1)->nr_handle == NULL/
{
self->trace = 1;
self->hostp = arg0;
self->handle = arg1;
}
clnt_tli_kcreate:return
/self->trace == 1/
{
self->kcreate_ret = arg1;
}
cmn_err:entry
/self->trace == 1/
{
printf("kcreate returned %d and CLSET_NODELAYONERR returned false\n",
self->kcreate_ret);
printf("args of refresh_nlm_rpc() follow:\n");
print(*((struct nlm_host *)self->hostp));
print(*((nlm_rpc_t *)self->handle));
stack();
}
refresh_nlm_rpc:return
/self->trace == 1/
{
self->trace = 0;
}
And got a piece of output:
kcreate returned 0 and CLSET_NODELAYONERR returned false
args of refresh_nlm_rpc() follow:
struct nlm_host {
kmutex_t nh_lock = {
void *[1] _opaque = [ 0 ]
}
volatile uint_t nh_refs = 0x1
struct nh_link = {
struct nlm_host *tqe_next = 0
struct nlm_host **tqe_prev = 0
}
avl_node_t nh_by_addr = {
struct avl_node *[2] avl_child = [ 0, 0 ]
uintptr_t avl_pcb = 0x1
}
char *nh_name = 0xffffff09144031c8
char *nh_netid = 0xffffff09b124bae8
struct knetconfig nh_knc = {
unsigned int knc_semantics = 0x1
caddr_t knc_protofmly = 0xfffffffff843274c
caddr_t knc_proto = 0xfffffffff8432751
dev_t knc_rdev = 0x10000000000
unsigned int [8] knc_unused = [ 0, 0, 0, 0, 0, 0, 0, 0 ]
}
struct netbuf nh_addr = {
unsigned int maxlen = 0x10
unsigned int len = 0x10
char *buf = 0xffffff0ba154c3b0
}
sysid_t nh_sysid = 0x9
int32_t nh_state = 0
clock_t nh_idle_timeout = 0
uint8_t nh_flags = 0
kcondvar_t nh_recl_cv = {
ushort_t _opaque = 0
}
kcondvar_t nh_rpcb_cv = {
ushort_t _opaque = 0
}
enum clnt_stat nh_rpcb_ustat = RPC_SUCCESS
enum nlm_rpcb_state nh_rpcb_state = NRPCB_UPDATED
struct nlm_rpch_list nh_rpchc = {
struct nlm_rpc *tqh_first = 0
struct nlm_rpc **tqh_last = 0xffffff090fec6930
}
mod_hash_t *nh_vholds_by_vp = 0xffffff09ee8b6500
struct nlm_vhold_list nh_vholds_list = {
struct nlm_vhold *tqh_first = 0
struct nlm_vhold **tqh_last = 0xffffff090fec6948
}
struct nlm_shres *nh_shrlist = 0
kthread_t *nh_reclaimer = 0
}nlm_rpc_t {
CLIENT *nr_handle = 0xffffff0b308dd700
rpcvers_t nr_vers = 0x4
struct nr_link = {
struct nlm_rpc *tqe_next = 0
struct nlm_rpc **tqe_prev = 0
}
}
klmmod`refresh_nlm_rpc+0xf8
klmmod`nlm_host_get_rpc+0xc6
klmmod`nlm_do_unlock+0xe1
klmmod`nlm4_unlock_msg_4_svc+0x4a
klmmod`nlm_dispatch+0xe6
klmmod`nlm_prog_4+0x34
rpcmod`svc_getreq+0x1c1
rpcmod`svc_run+0xe0
rpcmod`svc_do_run+0x8e
nfs`nfssys+0xf1
unix`_sys_sysenter_post_swapgs+0x149
An NLM expert may be able to tell what's going on immediately, but I will have to get this script to be more verbose. Clues welcome, but I think I can manage with a bit of time.
Updated by Marcel Telka about 6 years ago
- Related to Bug #4463: NLM fails wrongly on clnt_control(). added
Updated by Dan McDonald about 6 years ago
I've updated the DTrace script, and see more useful (hostname redacted) output:
#!/usr/sbin/dtrace -Cs
refresh_nlm_rpc:entry
/((nlm_rpc_t *)arg1)->nr_handle == NULL/
{
self->trace = 1;
self->hostp = arg0;
self->handle = arg1;
}
clnt_tli_kcreate:return
/self->trace == 1/
{
self->kcreate_ret = arg1;
}
cmn_err:entry
/self->trace == 1/
{
printf("\n\nkcreate returned %d and CLSET_NODELAYONERR returned false\n"
, self->kcreate_ret);
printf("args of refresh_nlm_rpc() follow:\n");
print(*((struct nlm_host *)self->hostp));
printf("\n");
print(*((nlm_rpc_t *)self->handle));
printf("\n");
print(*((CLIENT *)((nlm_rpc_t *)self->handle)->nr_handle));
printf("\n");
print(*((struct client_ops *)
((CLIENT *)((nlm_rpc_t *)self->handle)->nr_handle)->cl_ops));
printf("\n");
printf("Host name %s ; netid %s\n",
stringof(((struct nlm_host *)self->hostp)->nh_name),
stringof(((struct nlm_host *)self->hostp)->nh_netid));
printf("\n");
printf("\n");
stack();
}
refresh_nlm_rpc:return
/self->trace == 1/
{
self->trace = 0;
}
dtrace: script '/export/home/danmcd/clset-nodelayonerr.d' matched 4 probes
CPU ID FUNCTION:NAME
0 25166 cmn_err:entry
kcreate returned 0 and CLSET_NODELAYONERR returned false
args of refresh_nlm_rpc() follow:
struct nlm_host {
kmutex_t nh_lock = {
void *[1] _opaque = [ 0 ]
}
volatile uint_t nh_refs = 0x1
struct nh_link = {
struct nlm_host *tqe_next = 0
struct nlm_host **tqe_prev = 0
}
avl_node_t nh_by_addr = {
struct avl_node *[2] avl_child = [ 0, 0 ]
uintptr_t avl_pcb = 0x1
}
char *nh_name = 0xffffff0ba154c8c0
char *nh_netid = 0xffffff0ebf43ee30
struct knetconfig nh_knc = {
unsigned int knc_semantics = 0x1
caddr_t knc_protofmly = 0xfffffffff843274c
caddr_t knc_proto = 0xfffffffff8432751
dev_t knc_rdev = 0x10000000000
unsigned int [8] knc_unused = [ 0, 0, 0, 0, 0, 0, 0, 0 ]
}
struct netbuf nh_addr = {
unsigned int maxlen = 0x10
unsigned int len = 0x10
char *buf = 0xffffff0913f0a1c0
}
sysid_t nh_sysid = 0xb
int32_t nh_state = 0
clock_t nh_idle_timeout = 0
uint8_t nh_flags = 0
kcondvar_t nh_recl_cv = {
ushort_t _opaque = 0
}
kcondvar_t nh_rpcb_cv = {
ushort_t _opaque = 0
}
enum clnt_stat nh_rpcb_ustat = RPC_SUCCESS
enum nlm_rpcb_state nh_rpcb_state = NRPCB_UPDATED
struct nlm_rpch_list nh_rpchc = {
struct nlm_rpc *tqh_first = 0
struct nlm_rpc **tqh_last = 0xffffff090fec6750
}
mod_hash_t *nh_vholds_by_vp = 0xffffff09f0236180
struct nlm_vhold_list nh_vholds_list = {
struct nlm_vhold *tqh_first = 0
struct nlm_vhold **tqh_last = 0xffffff090fec6768
}
struct nlm_shres *nh_shrlist = 0
kthread_t *nh_reclaimer = 0
}
nlm_rpc_t {
CLIENT *nr_handle = 0xffffff091f016680
rpcvers_t nr_vers = 0x4
struct nr_link = {
struct nlm_rpc *tqe_next = 0
struct nlm_rpc **tqe_prev = 0
}
}
CLIENT {
AUTH *cl_auth = 0xffffff0915864a70
struct clnt_ops *cl_ops = 0xfffffffffbd301e0
caddr_t cl_private = 0xffffff091f016680
bool_t cl_nosignal = 0
}
struct client_ops <forward decl>
Host name <hostname-no-domain> ; netid udp
klmmod`refresh_nlm_rpc+0xf8
klmmod`nlm_host_get_rpc+0xc6
klmmod`nlm_do_unlock+0xe1
klmmod`nlm4_unlock_msg_4_svc+0x4a
klmmod`nlm_dispatch+0xe6
klmmod`nlm_prog_4+0x34
rpcmod`svc_getreq+0x1c1
rpcmod`svc_run+0xe0
rpcmod`svc_do_run+0x8e
nfs`nfssys+0xf1
unix`_sys_sysenter_post_swapgs+0x149
It looks like we're doing CLSET_NODELAYONERR with a UDP session. Should we be so chatty in that case?
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