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Close some potential races around socket start/close.

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There are some reports about panics on ic->ic_socket NULL derefence.
This kind of races is the only way I can imagine it to happen.

MFC after:	2 weeks
This commit is contained in:
Alexander Motin 2015-05-15 13:36:50 +00:00
parent 64a8a34dea
commit 5b157f2144
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=282970
1 changed files with 54 additions and 54 deletions
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108
sys/dev/iscsi/icl_soft.c
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@ -773,10 +773,6 @@ icl_receive_thread(void *arg)
ic = arg;
so = ic->ic_socket;
ICL_CONN_LOCK(ic);
ic->ic_receive_running = true;
ICL_CONN_UNLOCK(ic);
for (;;) {
if (ic->ic_disconnecting) {
//ICL_DEBUG("terminating");
@ -998,8 +994,6 @@ icl_send_thread(void *arg)
STAILQ_INIT(&queue);
ICL_CONN_LOCK(ic);
ic->ic_send_running = true;
for (;;) {
for (;;) {
/*
@ -1274,25 +1268,6 @@ icl_conn_start(struct icl_conn *ic)
return (error);
}
/*
* Start threads.
*/
error = kthread_add(icl_send_thread, ic, NULL, NULL, 0, 0, "%stx",
ic->ic_name);
if (error != 0) {
ICL_WARN("kthread_add(9) failed with error %d", error);
icl_soft_conn_close(ic);
return (error);
}
error = kthread_add(icl_receive_thread, ic, NULL, NULL, 0, 0, "%srx",
ic->ic_name);
if (error != 0) {
ICL_WARN("kthread_add(9) failed with error %d", error);
icl_soft_conn_close(ic);
return (error);
}
/*
* Register socket upcall, to get notified about incoming PDUs
* and free space to send outgoing ones.
@ -1304,6 +1279,35 @@ icl_conn_start(struct icl_conn *ic)
soupcall_set(ic->ic_socket, SO_RCV, icl_soupcall_receive, ic);
SOCKBUF_UNLOCK(&ic->ic_socket->so_rcv);
/*
* Start threads.
*/
ICL_CONN_LOCK(ic);
ic->ic_send_running = ic->ic_receive_running = true;
ICL_CONN_UNLOCK(ic);
error = kthread_add(icl_send_thread, ic, NULL, NULL, 0, 0, "%stx",
ic->ic_name);
if (error != 0) {
ICL_WARN("kthread_add(9) failed with error %d", error);
ICL_CONN_LOCK(ic);
ic->ic_send_running = ic->ic_receive_running = false;
cv_signal(&ic->ic_send_cv);
ICL_CONN_UNLOCK(ic);
icl_soft_conn_close(ic);
return (error);
}
error = kthread_add(icl_receive_thread, ic, NULL, NULL, 0, 0, "%srx",
ic->ic_name);
if (error != 0) {
ICL_WARN("kthread_add(9) failed with error %d", error);
ICL_CONN_LOCK(ic);
ic->ic_receive_running = false;
cv_signal(&ic->ic_send_cv);
ICL_CONN_UNLOCK(ic);
icl_soft_conn_close(ic);
return (error);
}
return (0);
}
@ -1357,47 +1361,43 @@ void
icl_soft_conn_close(struct icl_conn *ic)
{
struct icl_pdu *pdu;
ICL_CONN_LOCK_ASSERT_NOT(ic);
struct socket *so;
ICL_CONN_LOCK(ic);
if (ic->ic_socket == NULL) {
/*
* Wake up the threads, so they can properly terminate.
*/
ic->ic_disconnecting = true;
while (ic->ic_receive_running || ic->ic_send_running) {
cv_signal(&ic->ic_receive_cv);
cv_signal(&ic->ic_send_cv);
cv_wait(&ic->ic_send_cv, ic->ic_lock);
}
/* Some other thread could close the connection same time. */
so = ic->ic_socket;
if (so == NULL) {
ICL_CONN_UNLOCK(ic);
return;
}
ic->ic_socket = NULL;
/*
* Deregister socket upcalls.
*/
ICL_CONN_UNLOCK(ic);
SOCKBUF_LOCK(&ic->ic_socket->so_snd);
if (ic->ic_socket->so_snd.sb_upcall != NULL)
soupcall_clear(ic->ic_socket, SO_SND);
SOCKBUF_UNLOCK(&ic->ic_socket->so_snd);
SOCKBUF_LOCK(&ic->ic_socket->so_rcv);
if (ic->ic_socket->so_rcv.sb_upcall != NULL)
soupcall_clear(ic->ic_socket, SO_RCV);
SOCKBUF_UNLOCK(&ic->ic_socket->so_rcv);
SOCKBUF_LOCK(&so->so_snd);
if (so->so_snd.sb_upcall != NULL)
soupcall_clear(so, SO_SND);
SOCKBUF_UNLOCK(&so->so_snd);
SOCKBUF_LOCK(&so->so_rcv);
if (so->so_rcv.sb_upcall != NULL)
soupcall_clear(so, SO_RCV);
SOCKBUF_UNLOCK(&so->so_rcv);
soclose(so);
ICL_CONN_LOCK(ic);
ic->ic_disconnecting = true;
/*
* Wake up the threads, so they can properly terminate.
*/
while (ic->ic_receive_running || ic->ic_send_running) {
//ICL_DEBUG("waiting for send/receive threads to terminate");
cv_signal(&ic->ic_receive_cv);
cv_signal(&ic->ic_send_cv);
cv_wait(&ic->ic_send_cv, ic->ic_lock);
}
//ICL_DEBUG("send/receive threads terminated");
ICL_CONN_UNLOCK(ic);
soclose(ic->ic_socket);
ICL_CONN_LOCK(ic);
ic->ic_socket = NULL;
if (ic->ic_receive_pdu != NULL) {
//ICL_DEBUG("freeing partially received PDU");
icl_pdu_free(ic->ic_receive_pdu);