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-rw-r--r--net/unix/af_unix.c18
-rw-r--r--net/unix/diag.c2
-rw-r--r--net/unix/garbage.c37
-rw-r--r--net/unix/scm.c12
4 files changed, 41 insertions, 28 deletions
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 237488b1b..224b1fdc8 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -817,11 +817,11 @@ static struct sock *unix_create1(struct net *net, struct socket *sock, int kern)
sk->sk_write_space = unix_write_space;
sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen;
sk->sk_destruct = unix_sock_destructor;
- u = unix_sk(sk);
+ u = unix_sk(sk);
+ u->inflight = 0;
u->path.dentry = NULL;
u->path.mnt = NULL;
spin_lock_init(&u->lock);
- atomic_long_set(&u->inflight, 0);
INIT_LIST_HEAD(&u->link);
mutex_init(&u->iolock); /* single task reading lock */
mutex_init(&u->bindlock); /* single task binding lock */
@@ -1126,13 +1126,11 @@ static void unix_state_double_lock(struct sock *sk1, struct sock *sk2)
unix_state_lock(sk1);
return;
}
- if (sk1 < sk2) {
- unix_state_lock(sk1);
- unix_state_lock_nested(sk2);
- } else {
- unix_state_lock(sk2);
- unix_state_lock_nested(sk1);
- }
+ if (sk1 > sk2)
+ swap(sk1, sk2);
+
+ unix_state_lock(sk1);
+ unix_state_lock_nested(sk2, U_LOCK_SECOND);
}
static void unix_state_double_unlock(struct sock *sk1, struct sock *sk2)
@@ -1352,7 +1350,7 @@ restart:
goto out_unlock;
}
- unix_state_lock_nested(sk);
+ unix_state_lock_nested(sk, U_LOCK_SECOND);
if (sk->sk_state != st) {
unix_state_unlock(sk);
diff --git a/net/unix/diag.c b/net/unix/diag.c
index 951b33fa8..2975e7a06 100644
--- a/net/unix/diag.c
+++ b/net/unix/diag.c
@@ -83,7 +83,7 @@ static int sk_diag_dump_icons(struct sock *sk, struct sk_buff *nlskb)
* queue lock. With the other's queue locked it's
* OK to lock the state.
*/
- unix_state_lock_nested(req);
+ unix_state_lock_nested(req, U_LOCK_DIAG);
peer = unix_sk(req)->peer;
buf[i++] = (peer ? sock_i_ino(peer) : 0);
unix_state_unlock(req);
diff --git a/net/unix/garbage.c b/net/unix/garbage.c
index dc2763540..133ba5be4 100644
--- a/net/unix/garbage.c
+++ b/net/unix/garbage.c
@@ -166,17 +166,18 @@ static void scan_children(struct sock *x, void (*func)(struct unix_sock *),
static void dec_inflight(struct unix_sock *usk)
{
- atomic_long_dec(&usk->inflight);
+ usk->inflight--;
}
static void inc_inflight(struct unix_sock *usk)
{
- atomic_long_inc(&usk->inflight);
+ usk->inflight++;
}
static void inc_inflight_move_tail(struct unix_sock *u)
{
- atomic_long_inc(&u->inflight);
+ u->inflight++;
+
/* If this still might be part of a cycle, move it to the end
* of the list, so that it's checked even if it was already
* passed over
@@ -198,7 +199,7 @@ void wait_for_unix_gc(void)
if (READ_ONCE(unix_tot_inflight) > UNIX_INFLIGHT_TRIGGER_GC &&
!READ_ONCE(gc_in_progress))
unix_gc();
- wait_event(unix_gc_wait, gc_in_progress == false);
+ wait_event(unix_gc_wait, !READ_ONCE(gc_in_progress));
}
/* The external entry point: unix_gc() */
@@ -234,20 +235,34 @@ void unix_gc(void)
* receive queues. Other, non candidate sockets _can_ be
* added to queue, so we must make sure only to touch
* candidates.
+ *
+ * Embryos, though never candidates themselves, affect which
+ * candidates are reachable by the garbage collector. Before
+ * being added to a listener's queue, an embryo may already
+ * receive data carrying SCM_RIGHTS, potentially making the
+ * passed socket a candidate that is not yet reachable by the
+ * collector. It becomes reachable once the embryo is
+ * enqueued. Therefore, we must ensure that no SCM-laden
+ * embryo appears in a (candidate) listener's queue between
+ * consecutive scan_children() calls.
*/
list_for_each_entry_safe(u, next, &gc_inflight_list, link) {
+ struct sock *sk = &u->sk;
long total_refs;
- long inflight_refs;
- total_refs = file_count(u->sk.sk_socket->file);
- inflight_refs = atomic_long_read(&u->inflight);
+ total_refs = file_count(sk->sk_socket->file);
- BUG_ON(inflight_refs < 1);
- BUG_ON(total_refs < inflight_refs);
- if (total_refs == inflight_refs) {
+ BUG_ON(!u->inflight);
+ BUG_ON(total_refs < u->inflight);
+ if (total_refs == u->inflight) {
list_move_tail(&u->link, &gc_candidates);
__set_bit(UNIX_GC_CANDIDATE, &u->gc_flags);
__set_bit(UNIX_GC_MAYBE_CYCLE, &u->gc_flags);
+
+ if (sk->sk_state == TCP_LISTEN) {
+ unix_state_lock_nested(sk, U_LOCK_GC_LISTENER);
+ unix_state_unlock(sk);
+ }
}
}
@@ -271,7 +286,7 @@ void unix_gc(void)
/* Move cursor to after the current position. */
list_move(&cursor, &u->link);
- if (atomic_long_read(&u->inflight) > 0) {
+ if (u->inflight) {
list_move_tail(&u->link, &not_cycle_list);
__clear_bit(UNIX_GC_MAYBE_CYCLE, &u->gc_flags);
scan_children(&u->sk, inc_inflight_move_tail, NULL);
diff --git a/net/unix/scm.c b/net/unix/scm.c
index e8e2a00bb..4eff7da9f 100644
--- a/net/unix/scm.c
+++ b/net/unix/scm.c
@@ -34,10 +34,8 @@ struct sock *unix_get_socket(struct file *filp)
/* PF_UNIX ? */
if (s && sock->ops && sock->ops->family == PF_UNIX)
u_sock = s;
- } else {
- /* Could be an io_uring instance */
- u_sock = io_uring_get_socket(filp);
}
+
return u_sock;
}
EXPORT_SYMBOL(unix_get_socket);
@@ -54,12 +52,13 @@ void unix_inflight(struct user_struct *user, struct file *fp)
if (s) {
struct unix_sock *u = unix_sk(s);
- if (atomic_long_inc_return(&u->inflight) == 1) {
+ if (!u->inflight) {
BUG_ON(!list_empty(&u->link));
list_add_tail(&u->link, &gc_inflight_list);
} else {
BUG_ON(list_empty(&u->link));
}
+ u->inflight++;
/* Paired with READ_ONCE() in wait_for_unix_gc() */
WRITE_ONCE(unix_tot_inflight, unix_tot_inflight + 1);
}
@@ -76,10 +75,11 @@ void unix_notinflight(struct user_struct *user, struct file *fp)
if (s) {
struct unix_sock *u = unix_sk(s);
- BUG_ON(!atomic_long_read(&u->inflight));
+ BUG_ON(!u->inflight);
BUG_ON(list_empty(&u->link));
- if (atomic_long_dec_and_test(&u->inflight))
+ u->inflight--;
+ if (!u->inflight)
list_del_init(&u->link);
/* Paired with READ_ONCE() in wait_for_unix_gc() */
WRITE_ONCE(unix_tot_inflight, unix_tot_inflight - 1);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-23 00:15:53 +0000