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dlm for 6.3

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This patch set fixes some races in the lowcomms startup and shutdown code
 that were found by targetted stress testing that quickly and repeatedly
 joins and leaves lockspaces.
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Merge tag 'dlm-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm

Pull dlm updates from David Teigland:
 "This fixes some races in the lowcomms startup and shutdown code that
  were found by targeted stress testing that quickly and repeatedly
  joins and leaves lockspaces"

* tag 'dlm-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm:
  fs: dlm: remove unnecessary waker_up() calls
  fs: dlm: move state change into else branch
  fs: dlm: remove newline in log_print
  fs: dlm: reduce the shutdown timeout to 5 secs
  fs: dlm: make dlm sequence id more robust
  fs: dlm: wait until all midcomms nodes detect version
  fs: dlm: ignore unexpected non dlm opts msgs
  fs: dlm: bring back previous shutdown handling
  fs: dlm: send FIN ack back in right cases
  fs: dlm: move sending fin message into state change handling
  fs: dlm: don't set stop rx flag after node reset
  fs: dlm: fix race setting stop tx flag
  fs: dlm: be sure to call dlm_send_queue_flush()
  fs: dlm: fix use after free in midcomms commit
  fs: dlm: start midcomms before scand
  fs/dlm: Remove "select SRCU"
  fs: dlm: fix return value check in dlm_memory_init()
This commit is contained in:
Linus Torvalds 2023-02-20 13:05:24 -08:00
commit eca3a04f14
6 changed files with 137 additions and 98 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
fs/dlm/Kconfig
View File

@ -4,7 +4,6 @@ menuconfig DLM
depends on INET
depends on SYSFS && CONFIGFS_FS && (IPV6 || IPV6=n)
select IP_SCTP
select SRCU
help
A general purpose distributed lock manager for kernel or userspace
applications.

23
fs/dlm/lockspace.c
View File

@ -381,23 +381,23 @@ static int threads_start(void)
{
int error;
error = dlm_scand_start();
if (error) {
log_print("cannot start dlm_scand thread %d", error);
goto fail;
}
/* Thread for sending/receiving messages for all lockspace's */
error = dlm_midcomms_start();
if (error) {
log_print("cannot start dlm midcomms %d", error);
goto scand_fail;
goto fail;
}
error = dlm_scand_start();
if (error) {
log_print("cannot start dlm_scand thread %d", error);
goto midcomms_fail;
}
return 0;
scand_fail:
dlm_scand_stop();
midcomms_fail:
dlm_midcomms_stop();
fail:
return error;
}
@ -572,7 +572,7 @@ static int new_lockspace(const char *name, const char *cluster,
spin_lock_init(&ls->ls_rcom_spin);
get_random_bytes(&ls->ls_rcom_seq, sizeof(uint64_t));
ls->ls_recover_status = 0;
ls->ls_recover_seq = 0;
ls->ls_recover_seq = get_random_u64();
ls->ls_recover_args = NULL;
init_rwsem(&ls->ls_in_recovery);
init_rwsem(&ls->ls_recv_active);
@ -820,6 +820,9 @@ static int release_lockspace(struct dlm_ls *ls, int force)
return rv;
}
if (ls_count == 1)
dlm_midcomms_version_wait();
dlm_device_deregister(ls);
if (force < 3 && dlm_user_daemon_available())

67
fs/dlm/lowcomms.c
View File

@ -61,6 +61,7 @@
#include "memory.h"
#include "config.h"
#define DLM_SHUTDOWN_WAIT_TIMEOUT msecs_to_jiffies(5000)
#define NEEDED_RMEM (4*1024*1024)
struct connection {
@ -99,6 +100,7 @@ struct connection {
struct connection *othercon;
struct work_struct rwork; /* receive worker */
struct work_struct swork; /* send worker */
wait_queue_head_t shutdown_wait;
unsigned char rx_leftover_buf[DLM_MAX_SOCKET_BUFSIZE];
int rx_leftover;
int mark;
@ -282,6 +284,7 @@ static void dlm_con_init(struct connection *con, int nodeid)
INIT_WORK(&con->swork, process_send_sockets);
INIT_WORK(&con->rwork, process_recv_sockets);
spin_lock_init(&con->addrs_lock);
init_waitqueue_head(&con->shutdown_wait);
}
/*
@ -790,6 +793,43 @@ static void close_connection(struct connection *con, bool and_other)
up_write(&con->sock_lock);
}
static void shutdown_connection(struct connection *con, bool and_other)
{
int ret;
if (con->othercon && and_other)
shutdown_connection(con->othercon, false);
flush_workqueue(io_workqueue);
down_read(&con->sock_lock);
/* nothing to shutdown */
if (!con->sock) {
up_read(&con->sock_lock);
return;
}
ret = kernel_sock_shutdown(con->sock, SHUT_WR);
up_read(&con->sock_lock);
if (ret) {
log_print("Connection %p failed to shutdown: %d will force close",
con, ret);
goto force_close;
} else {
ret = wait_event_timeout(con->shutdown_wait, !con->sock,
DLM_SHUTDOWN_WAIT_TIMEOUT);
if (ret == 0) {
log_print("Connection %p shutdown timed out, will force close",
con);
goto force_close;
}
}
return;
force_close:
close_connection(con, false);
}
static struct processqueue_entry *new_processqueue_entry(int nodeid,
int buflen)
{
@ -1488,6 +1528,7 @@ static void process_recv_sockets(struct work_struct *work)
break;
case DLM_IO_EOF:
close_connection(con, false);
wake_up(&con->shutdown_wait);
/* CF_RECV_PENDING cleared */
break;
case DLM_IO_RESCHED:
@ -1695,6 +1736,9 @@ static int work_start(void)
void dlm_lowcomms_shutdown(void)
{
struct connection *con;
int i, idx;
/* stop lowcomms_listen_data_ready calls */
lock_sock(listen_con.sock->sk);
listen_con.sock->sk->sk_data_ready = listen_sock.sk_data_ready;
@ -1703,29 +1747,20 @@ void dlm_lowcomms_shutdown(void)
cancel_work_sync(&listen_con.rwork);
dlm_close_sock(&listen_con.sock);
flush_workqueue(process_workqueue);
}
void dlm_lowcomms_shutdown_node(int nodeid, bool force)
{
struct connection *con;
int idx;
idx = srcu_read_lock(&connections_srcu);
con = nodeid2con(nodeid, 0);
if (WARN_ON_ONCE(!con)) {
srcu_read_unlock(&connections_srcu, idx);
return;
}
flush_work(&con->swork);
for (i = 0; i < CONN_HASH_SIZE; i++) {
hlist_for_each_entry_rcu(con, &connection_hash[i], list) {
shutdown_connection(con, true);
stop_connection_io(con);
WARN_ON_ONCE(!force && !list_empty(&con->writequeue));
flush_workqueue(process_workqueue);
close_connection(con, true);
clean_one_writequeue(con);
if (con->othercon)
clean_one_writequeue(con->othercon);
allow_connection_io(con);
}
}
srcu_read_unlock(&connections_srcu, idx);
}

2
fs/dlm/memory.c
View File

@ -51,7 +51,7 @@ int __init dlm_memory_init(void)
cb_cache = kmem_cache_create("dlm_cb", sizeof(struct dlm_callback),
__alignof__(struct dlm_callback), 0,
NULL);
if (!rsb_cache)
if (!cb_cache)
goto cb;
return 0;

123
fs/dlm/midcomms.c
View File

@ -146,8 +146,8 @@
/* init value for sequence numbers for testing purpose only e.g. overflows */
#define DLM_SEQ_INIT 0
/* 3 minutes wait to sync ending of dlm */
#define DLM_SHUTDOWN_TIMEOUT msecs_to_jiffies(3 * 60 * 1000)
/* 5 seconds wait to sync ending of dlm */
#define DLM_SHUTDOWN_TIMEOUT msecs_to_jiffies(5000)
#define DLM_VERSION_NOT_SET 0
struct midcomms_node {
@ -375,7 +375,7 @@ static int dlm_send_ack(int nodeid, uint32_t seq)
struct dlm_msg *msg;
char *ppc;
msg = dlm_lowcomms_new_msg(nodeid, mb_len, GFP_NOFS, &ppc,
msg = dlm_lowcomms_new_msg(nodeid, mb_len, GFP_ATOMIC, &ppc,
NULL, NULL);
if (!msg)
return -ENOMEM;
@ -402,10 +402,11 @@ static int dlm_send_fin(struct midcomms_node *node,
struct dlm_mhandle *mh;
char *ppc;
mh = dlm_midcomms_get_mhandle(node->nodeid, mb_len, GFP_NOFS, &ppc);
mh = dlm_midcomms_get_mhandle(node->nodeid, mb_len, GFP_ATOMIC, &ppc);
if (!mh)
return -ENOMEM;
set_bit(DLM_NODE_FLAG_STOP_TX, &node->flags);
mh->ack_rcv = ack_rcv;
m_header = (struct dlm_header *)ppc;
@ -417,7 +418,6 @@ static int dlm_send_fin(struct midcomms_node *node,
pr_debug("sending fin msg to node %d\n", node->nodeid);
dlm_midcomms_commit_mhandle(mh, NULL, 0);
set_bit(DLM_NODE_FLAG_STOP_TX, &node->flags);
return 0;
}
@ -467,7 +467,7 @@ static void dlm_pas_fin_ack_rcv(struct midcomms_node *node)
break;
default:
spin_unlock(&node->state_lock);
log_print("%s: unexpected state: %d\n",
log_print("%s: unexpected state: %d",
__func__, node->state);
WARN_ON_ONCE(1);
return;
@ -498,18 +498,14 @@ static void dlm_midcomms_receive_buffer(union dlm_packet *p,
switch (p->header.h_cmd) {
case DLM_FIN:
/* send ack before fin */
dlm_send_ack(node->nodeid, node->seq_next);
spin_lock(&node->state_lock);
pr_debug("receive fin msg from node %d with state %s\n",
node->nodeid, dlm_state_str(node->state));
switch (node->state) {
case DLM_ESTABLISHED:
node->state = DLM_CLOSE_WAIT;
pr_debug("switch node %d to state %s\n",
node->nodeid, dlm_state_str(node->state));
dlm_send_ack(node->nodeid, node->seq_next);
/* passive shutdown DLM_LAST_ACK case 1
* additional we check if the node is used by
* cluster manager events at all.
@ -518,34 +514,38 @@ static void dlm_midcomms_receive_buffer(union dlm_packet *p,
node->state = DLM_LAST_ACK;
pr_debug("switch node %d to state %s case 1\n",
node->nodeid, dlm_state_str(node->state));
spin_unlock(&node->state_lock);
goto send_fin;
set_bit(DLM_NODE_FLAG_STOP_RX, &node->flags);
dlm_send_fin(node, dlm_pas_fin_ack_rcv);
} else {
node->state = DLM_CLOSE_WAIT;
pr_debug("switch node %d to state %s\n",
node->nodeid, dlm_state_str(node->state));
}
break;
case DLM_FIN_WAIT1:
dlm_send_ack(node->nodeid, node->seq_next);
node->state = DLM_CLOSING;
set_bit(DLM_NODE_FLAG_STOP_RX, &node->flags);
pr_debug("switch node %d to state %s\n",
node->nodeid, dlm_state_str(node->state));
break;
case DLM_FIN_WAIT2:
dlm_send_ack(node->nodeid, node->seq_next);
midcomms_node_reset(node);
pr_debug("switch node %d to state %s\n",
node->nodeid, dlm_state_str(node->state));
wake_up(&node->shutdown_wait);
break;
case DLM_LAST_ACK:
/* probably remove_member caught it, do nothing */
break;
default:
spin_unlock(&node->state_lock);
log_print("%s: unexpected state: %d\n",
log_print("%s: unexpected state: %d",
__func__, node->state);
WARN_ON_ONCE(1);
return;
}
spin_unlock(&node->state_lock);
set_bit(DLM_NODE_FLAG_STOP_RX, &node->flags);
break;
default:
WARN_ON_ONCE(test_bit(DLM_NODE_FLAG_STOP_RX, &node->flags));
@ -564,12 +564,6 @@ static void dlm_midcomms_receive_buffer(union dlm_packet *p,
log_print_ratelimited("ignore dlm msg because seq mismatch, seq: %u, expected: %u, nodeid: %d",
seq, node->seq_next, node->nodeid);
}
return;
send_fin:
set_bit(DLM_NODE_FLAG_STOP_RX, &node->flags);
dlm_send_fin(node, dlm_pas_fin_ack_rcv);
}
static struct midcomms_node *
@ -612,16 +606,8 @@ dlm_midcomms_recv_node_lookup(int nodeid, const union dlm_packet *p,
case DLM_ESTABLISHED:
break;
default:
/* some invalid state passive shutdown
* was failed, we try to reset and
* hope it will go on.
*/
log_print("reset node %d because shutdown stuck",
node->nodeid);
midcomms_node_reset(node);
node->state = DLM_ESTABLISHED;
break;
spin_unlock(&node->state_lock);
return NULL;
}
spin_unlock(&node->state_lock);
}
@ -671,6 +657,7 @@ static int dlm_midcomms_version_check_3_2(struct midcomms_node *node)
switch (node->version) {
case DLM_VERSION_NOT_SET:
node->version = DLM_VERSION_3_2;
wake_up(&node->shutdown_wait);
log_print("version 0x%08x for node %d detected", DLM_VERSION_3_2,
node->nodeid);
break;
@ -840,6 +827,7 @@ static int dlm_midcomms_version_check_3_1(struct midcomms_node *node)
switch (node->version) {
case DLM_VERSION_NOT_SET:
node->version = DLM_VERSION_3_1;
wake_up(&node->shutdown_wait);
log_print("version 0x%08x for node %d detected", DLM_VERSION_3_1,
node->nodeid);
break;
@ -1214,8 +1202,15 @@ void dlm_midcomms_commit_mhandle(struct dlm_mhandle *mh,
dlm_free_mhandle(mh);
break;
case DLM_VERSION_3_2:
/* held rcu read lock here, because we sending the
* dlm message out, when we do that we could receive
* an ack back which releases the mhandle and we
* get a use after free.
*/
rcu_read_lock();
dlm_midcomms_commit_msg_3_2(mh, name, namelen);
srcu_read_unlock(&nodes_srcu, mh->idx);
rcu_read_unlock();
break;
default:
srcu_read_unlock(&nodes_srcu, mh->idx);
@ -1266,7 +1261,6 @@ static void dlm_act_fin_ack_rcv(struct midcomms_node *node)
midcomms_node_reset(node);
pr_debug("switch node %d to state %s\n",
node->nodeid, dlm_state_str(node->state));
wake_up(&node->shutdown_wait);
break;
case DLM_CLOSED:
/* not valid but somehow we got what we want */
@ -1274,7 +1268,7 @@ static void dlm_act_fin_ack_rcv(struct midcomms_node *node)
break;
default:
spin_unlock(&node->state_lock);
log_print("%s: unexpected state: %d\n",
log_print("%s: unexpected state: %d",
__func__, node->state);
WARN_ON_ONCE(1);
return;
@ -1362,11 +1356,11 @@ void dlm_midcomms_remove_member(int nodeid)
case DLM_CLOSE_WAIT:
/* passive shutdown DLM_LAST_ACK case 2 */
node->state = DLM_LAST_ACK;
spin_unlock(&node->state_lock);
pr_debug("switch node %d to state %s case 2\n",
node->nodeid, dlm_state_str(node->state));
goto send_fin;
set_bit(DLM_NODE_FLAG_STOP_RX, &node->flags);
dlm_send_fin(node, dlm_pas_fin_ack_rcv);
break;
case DLM_LAST_ACK:
/* probably receive fin caught it, do nothing */
break;
@ -1374,7 +1368,7 @@ void dlm_midcomms_remove_member(int nodeid)
/* already gone, do nothing */
break;
default:
log_print("%s: unexpected state: %d\n",
log_print("%s: unexpected state: %d",
__func__, node->state);
break;
}
@ -1382,12 +1376,6 @@ void dlm_midcomms_remove_member(int nodeid)
spin_unlock(&node->state_lock);
srcu_read_unlock(&nodes_srcu, idx);
return;
send_fin:
set_bit(DLM_NODE_FLAG_STOP_RX, &node->flags);
dlm_send_fin(node, dlm_pas_fin_ack_rcv);
srcu_read_unlock(&nodes_srcu, idx);
}
static void midcomms_node_release(struct rcu_head *rcu)
@ -1395,9 +1383,31 @@ static void midcomms_node_release(struct rcu_head *rcu)
struct midcomms_node *node = container_of(rcu, struct midcomms_node, rcu);
WARN_ON_ONCE(atomic_read(&node->send_queue_cnt));
dlm_send_queue_flush(node);
kfree(node);
}
void dlm_midcomms_version_wait(void)
{
struct midcomms_node *node;
int i, idx, ret;
idx = srcu_read_lock(&nodes_srcu);
for (i = 0; i < CONN_HASH_SIZE; i++) {
hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
ret = wait_event_timeout(node->shutdown_wait,
node->version != DLM_VERSION_NOT_SET ||
node->state == DLM_CLOSED ||
test_bit(DLM_NODE_FLAG_CLOSE, &node->flags),
DLM_SHUTDOWN_TIMEOUT);
if (!ret || test_bit(DLM_NODE_FLAG_CLOSE, &node->flags))
pr_debug("version wait timed out for node %d with state %s\n",
node->nodeid, dlm_state_str(node->state));
}
}
srcu_read_unlock(&nodes_srcu, idx);
}
static void midcomms_shutdown(struct midcomms_node *node)
{
int ret;
@ -1418,11 +1428,11 @@ static void midcomms_shutdown(struct midcomms_node *node)
node->state = DLM_FIN_WAIT1;
pr_debug("switch node %d to state %s case 2\n",
node->nodeid, dlm_state_str(node->state));
dlm_send_fin(node, dlm_act_fin_ack_rcv);
break;
case DLM_CLOSED:
/* we have what we want */
spin_unlock(&node->state_lock);
return;
break;
default:
/* busy to enter DLM_FIN_WAIT1, wait until passive
* done in shutdown_wait to enter DLM_CLOSED.
@ -1431,29 +1441,20 @@ static void midcomms_shutdown(struct midcomms_node *node)
}
spin_unlock(&node->state_lock);
if (node->state == DLM_FIN_WAIT1) {
dlm_send_fin(node, dlm_act_fin_ack_rcv);
if (DLM_DEBUG_FENCE_TERMINATION)
msleep(5000);
}
/* wait for other side dlm + fin */
ret = wait_event_timeout(node->shutdown_wait,
node->state == DLM_CLOSED ||
test_bit(DLM_NODE_FLAG_CLOSE, &node->flags),
DLM_SHUTDOWN_TIMEOUT);
if (!ret || test_bit(DLM_NODE_FLAG_CLOSE, &node->flags)) {
if (!ret || test_bit(DLM_NODE_FLAG_CLOSE, &node->flags))
pr_debug("active shutdown timed out for node %d with state %s\n",
node->nodeid, dlm_state_str(node->state));
midcomms_node_reset(node);
dlm_lowcomms_shutdown_node(node->nodeid, true);
return;
}
else
pr_debug("active shutdown done for node %d with state %s\n",
node->nodeid, dlm_state_str(node->state));
dlm_lowcomms_shutdown_node(node->nodeid, false);
}
void dlm_midcomms_shutdown(void)
@ -1461,8 +1462,6 @@ void dlm_midcomms_shutdown(void)
struct midcomms_node *node;
int i, idx;
dlm_lowcomms_shutdown();
mutex_lock(&close_lock);
idx = srcu_read_lock(&nodes_srcu);
for (i = 0; i < CONN_HASH_SIZE; i++) {
@ -1480,6 +1479,8 @@ void dlm_midcomms_shutdown(void)
}
srcu_read_unlock(&nodes_srcu, idx);
mutex_unlock(&close_lock);
dlm_lowcomms_shutdown();
}
int dlm_midcomms_close(int nodeid)

1
fs/dlm/midcomms.h
View File

@ -20,6 +20,7 @@ struct dlm_mhandle *dlm_midcomms_get_mhandle(int nodeid, int len,
gfp_t allocation, char **ppc);
void dlm_midcomms_commit_mhandle(struct dlm_mhandle *mh, const void *name,
int namelen);
void dlm_midcomms_version_wait(void);
int dlm_midcomms_close(int nodeid);
int dlm_midcomms_start(void);
void dlm_midcomms_stop(void);