This is a note to let you know that I've just added the patch titled
fs: dlm: fix mark setting deadlock
to the 5.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fs-dlm-fix-mark-setting-deadlock.patch
and it can be found in the queue-5.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit c7663374e7a6ce6c0daa0419e87bca0bb029ddbc
Author: Alexander Aring <aahringo@xxxxxxxxxx>
Date: Mon Mar 1 17:05:09 2021 -0500
fs: dlm: fix mark setting deadlock
[ Upstream commit e125fbeb538e5e35a00c6c8150a5361bef34814c ]
This patch fixes an deadlock issue when dlm_lowcomms_close() is called.
When dlm_lowcomms_close() is called the clusters_root.subsys.su_mutex is
held to remove configfs items. At this time we flushing (e.g.
cancel_work_sync()) the workers of send and recv workqueue. Due the fact
that we accessing configfs items (mark values), these workers will lock
clusters_root.subsys.su_mutex as well which are already hold by
dlm_lowcomms_close() and ends in a deadlock situation.
[67170.703046] ======================================================
[67170.703965] WARNING: possible circular locking dependency detected
[67170.704758] 5.11.0-rc4+ #22 Tainted: G W
[67170.705433] ------------------------------------------------------
[67170.706228] dlm_controld/280 is trying to acquire lock:
[67170.706915] ffff9f2f475a6948 ((wq_completion)dlm_recv){+.+.}-{0:0}, at: __flush_work+0x203/0x4c0
[67170.708026]
but task is already holding lock:
[67170.708758] ffffffffa132f878 (&clusters_root.subsys.su_mutex){+.+.}-{3:3}, at: configfs_rmdir+0x29b/0x310
[67170.710016]
which lock already depends on the new lock.
The new behaviour adds the mark value to the node address configuration
which doesn't require to held the clusters_root.subsys.su_mutex by
accessing mark values in a separate datastructure. However the mark
values can be set now only after a node address was set which is the
case when the user is using dlm_controld.
Signed-off-by: Alexander Aring <aahringo@xxxxxxxxxx>
Signed-off-by: David Teigland <teigland@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/dlm/config.c b/fs/dlm/config.c
index 49c5f9407098..582bffa09a66 100644
--- a/fs/dlm/config.c
+++ b/fs/dlm/config.c
@@ -688,6 +688,7 @@ static ssize_t comm_mark_show(struct config_item *item, char *buf)
static ssize_t comm_mark_store(struct config_item *item, const char *buf,
size_t len)
{
+ struct dlm_comm *comm;
unsigned int mark;
int rc;
@@ -695,7 +696,15 @@ static ssize_t comm_mark_store(struct config_item *item, const char *buf,
if (rc)
return rc;
- config_item_to_comm(item)->mark = mark;
+ if (mark == 0)
+ mark = dlm_config.ci_mark;
+
+ comm = config_item_to_comm(item);
+ rc = dlm_lowcomms_nodes_set_mark(comm->nodeid, mark);
+ if (rc)
+ return rc;
+
+ comm->mark = mark;
return len;
}
@@ -870,24 +879,6 @@ int dlm_comm_seq(int nodeid, uint32_t *seq)
return 0;
}
-void dlm_comm_mark(int nodeid, unsigned int *mark)
-{
- struct dlm_comm *cm;
-
- cm = get_comm(nodeid);
- if (!cm) {
- *mark = dlm_config.ci_mark;
- return;
- }
-
- if (cm->mark)
- *mark = cm->mark;
- else
- *mark = dlm_config.ci_mark;
-
- put_comm(cm);
-}
-
int dlm_our_nodeid(void)
{
return local_comm ? local_comm->nodeid : 0;
diff --git a/fs/dlm/config.h b/fs/dlm/config.h
index c210250a2581..d2cd4bd20313 100644
--- a/fs/dlm/config.h
+++ b/fs/dlm/config.h
@@ -48,7 +48,6 @@ void dlm_config_exit(void);
int dlm_config_nodes(char *lsname, struct dlm_config_node **nodes_out,
int *count_out);
int dlm_comm_seq(int nodeid, uint32_t *seq);
-void dlm_comm_mark(int nodeid, unsigned int *mark);
int dlm_our_nodeid(void);
int dlm_our_addr(struct sockaddr_storage *addr, int num);
diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index f7d2c52791f8..a4fabcced0f2 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -116,6 +116,7 @@ struct writequeue_entry {
struct dlm_node_addr {
struct list_head list;
int nodeid;
+ int mark;
int addr_count;
int curr_addr_index;
struct sockaddr_storage *addr[DLM_MAX_ADDR_COUNT];
@@ -303,7 +304,8 @@ static int addr_compare(const struct sockaddr_storage *x,
}
static int nodeid_to_addr(int nodeid, struct sockaddr_storage *sas_out,
- struct sockaddr *sa_out, bool try_new_addr)
+ struct sockaddr *sa_out, bool try_new_addr,
+ unsigned int *mark)
{
struct sockaddr_storage sas;
struct dlm_node_addr *na;
@@ -331,6 +333,8 @@ static int nodeid_to_addr(int nodeid, struct sockaddr_storage *sas_out,
if (!na->addr_count)
return -ENOENT;
+ *mark = na->mark;
+
if (sas_out)
memcpy(sas_out, &sas, sizeof(struct sockaddr_storage));
@@ -350,7 +354,8 @@ static int nodeid_to_addr(int nodeid, struct sockaddr_storage *sas_out,
return 0;
}
-static int addr_to_nodeid(struct sockaddr_storage *addr, int *nodeid)
+static int addr_to_nodeid(struct sockaddr_storage *addr, int *nodeid,
+ unsigned int *mark)
{
struct dlm_node_addr *na;
int rv = -EEXIST;
@@ -364,6 +369,7 @@ static int addr_to_nodeid(struct sockaddr_storage *addr, int *nodeid)
for (addr_i = 0; addr_i < na->addr_count; addr_i++) {
if (addr_compare(na->addr[addr_i], addr)) {
*nodeid = na->nodeid;
+ *mark = na->mark;
rv = 0;
goto unlock;
}
@@ -412,6 +418,7 @@ int dlm_lowcomms_addr(int nodeid, struct sockaddr_storage *addr, int len)
new_node->nodeid = nodeid;
new_node->addr[0] = new_addr;
new_node->addr_count = 1;
+ new_node->mark = dlm_config.ci_mark;
list_add(&new_node->list, &dlm_node_addrs);
spin_unlock(&dlm_node_addrs_spin);
return 0;
@@ -519,6 +526,23 @@ int dlm_lowcomms_connect_node(int nodeid)
return 0;
}
+int dlm_lowcomms_nodes_set_mark(int nodeid, unsigned int mark)
+{
+ struct dlm_node_addr *na;
+
+ spin_lock(&dlm_node_addrs_spin);
+ na = find_node_addr(nodeid);
+ if (!na) {
+ spin_unlock(&dlm_node_addrs_spin);
+ return -ENOENT;
+ }
+
+ na->mark = mark;
+ spin_unlock(&dlm_node_addrs_spin);
+
+ return 0;
+}
+
static void lowcomms_error_report(struct sock *sk)
{
struct connection *con;
@@ -867,7 +891,7 @@ static int accept_from_sock(struct listen_connection *con)
/* Get the new node's NODEID */
make_sockaddr(&peeraddr, 0, &len);
- if (addr_to_nodeid(&peeraddr, &nodeid)) {
+ if (addr_to_nodeid(&peeraddr, &nodeid, &mark)) {
unsigned char *b=(unsigned char *)&peeraddr;
log_print("connect from non cluster node");
print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE,
@@ -876,9 +900,6 @@ static int accept_from_sock(struct listen_connection *con)
return -1;
}
- dlm_comm_mark(nodeid, &mark);
- sock_set_mark(newsock->sk, mark);
-
log_print("got connection from %d", nodeid);
/* Check to see if we already have a connection to this node. This
@@ -892,6 +913,8 @@ static int accept_from_sock(struct listen_connection *con)
goto accept_err;
}
+ sock_set_mark(newsock->sk, mark);
+
mutex_lock(&newcon->sock_mutex);
if (newcon->sock) {
struct connection *othercon = newcon->othercon;
@@ -1016,8 +1039,6 @@ static void sctp_connect_to_sock(struct connection *con)
struct socket *sock;
unsigned int mark;
- dlm_comm_mark(con->nodeid, &mark);
-
mutex_lock(&con->sock_mutex);
/* Some odd races can cause double-connects, ignore them */
@@ -1030,7 +1051,7 @@ static void sctp_connect_to_sock(struct connection *con)
}
memset(&daddr, 0, sizeof(daddr));
- result = nodeid_to_addr(con->nodeid, &daddr, NULL, true);
+ result = nodeid_to_addr(con->nodeid, &daddr, NULL, true, &mark);
if (result < 0) {
log_print("no address for nodeid %d", con->nodeid);
goto out;
@@ -1105,13 +1126,11 @@ out:
static void tcp_connect_to_sock(struct connection *con)
{
struct sockaddr_storage saddr, src_addr;
+ unsigned int mark;
int addr_len;
struct socket *sock = NULL;
- unsigned int mark;
int result;
- dlm_comm_mark(con->nodeid, &mark);
-
mutex_lock(&con->sock_mutex);
if (con->retries++ > MAX_CONNECT_RETRIES)
goto out;
@@ -1126,15 +1145,15 @@ static void tcp_connect_to_sock(struct connection *con)
if (result < 0)
goto out_err;
- sock_set_mark(sock->sk, mark);
-
memset(&saddr, 0, sizeof(saddr));
- result = nodeid_to_addr(con->nodeid, &saddr, NULL, false);
+ result = nodeid_to_addr(con->nodeid, &saddr, NULL, false, &mark);
if (result < 0) {
log_print("no address for nodeid %d", con->nodeid);
goto out_err;
}
+ sock_set_mark(sock->sk, mark);
+
add_sock(sock, con);
/* Bind to our cluster-known address connecting to avoid
diff --git a/fs/dlm/lowcomms.h b/fs/dlm/lowcomms.h
index 0918f9376489..790d6703b17e 100644
--- a/fs/dlm/lowcomms.h
+++ b/fs/dlm/lowcomms.h
@@ -21,6 +21,7 @@ int dlm_lowcomms_close(int nodeid);
void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc);
void dlm_lowcomms_commit_buffer(void *mh);
int dlm_lowcomms_connect_node(int nodeid);
+int dlm_lowcomms_nodes_set_mark(int nodeid, unsigned int mark);
int dlm_lowcomms_addr(int nodeid, struct sockaddr_storage *addr, int len);
#endif /* __LOWCOMMS_DOT_H__ */
