forked from mirrors/linux
fd86344823
Commit dcf70df204 ("af_unix: Fix up unix_edge.successor for embryo
socket.") added spin_lock(&unix_gc_lock) in accept() path, and it
caused regression in a stress test as reported by kernel test robot.
If the embryo socket is not part of the inflight graph, we need not
hold the lock.
To decide that in O(1) time and avoid the regression in the normal
use case,
1. add a new stat unix_sk(sk)->scm_stat.nr_unix_fds
2. count the number of inflight AF_UNIX sockets in the receive
queue under unix_state_lock()
3. move unix_update_edges() call under unix_state_lock()
4. avoid locking if nr_unix_fds is 0 in unix_update_edges()
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202404101427.92a08551-oliver.sang@intel.com
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240413021928.20946-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
139 lines
3.6 KiB
C
139 lines
3.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_NET_AFUNIX_H
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#define __LINUX_NET_AFUNIX_H
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#include <linux/socket.h>
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#include <linux/un.h>
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#include <linux/mutex.h>
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#include <linux/refcount.h>
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#include <net/sock.h>
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#if IS_ENABLED(CONFIG_UNIX)
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struct unix_sock *unix_get_socket(struct file *filp);
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#else
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static inline struct unix_sock *unix_get_socket(struct file *filp)
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{
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return NULL;
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}
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#endif
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extern unsigned int unix_tot_inflight;
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void unix_add_edges(struct scm_fp_list *fpl, struct unix_sock *receiver);
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void unix_del_edges(struct scm_fp_list *fpl);
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void unix_update_edges(struct unix_sock *receiver);
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int unix_prepare_fpl(struct scm_fp_list *fpl);
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void unix_destroy_fpl(struct scm_fp_list *fpl);
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void unix_gc(void);
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void wait_for_unix_gc(struct scm_fp_list *fpl);
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struct unix_vertex {
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struct list_head edges;
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struct list_head entry;
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struct list_head scc_entry;
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unsigned long out_degree;
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unsigned long index;
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unsigned long scc_index;
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};
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struct unix_edge {
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struct unix_sock *predecessor;
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struct unix_sock *successor;
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struct list_head vertex_entry;
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struct list_head stack_entry;
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};
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struct sock *unix_peer_get(struct sock *sk);
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#define UNIX_HASH_MOD (256 - 1)
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#define UNIX_HASH_SIZE (256 * 2)
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#define UNIX_HASH_BITS 8
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struct unix_address {
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refcount_t refcnt;
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int len;
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struct sockaddr_un name[];
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};
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struct unix_skb_parms {
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struct pid *pid; /* Skb credentials */
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kuid_t uid;
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kgid_t gid;
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struct scm_fp_list *fp; /* Passed files */
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#ifdef CONFIG_SECURITY_NETWORK
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u32 secid; /* Security ID */
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#endif
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u32 consumed;
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} __randomize_layout;
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struct scm_stat {
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atomic_t nr_fds;
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unsigned long nr_unix_fds;
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};
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#define UNIXCB(skb) (*(struct unix_skb_parms *)&((skb)->cb))
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/* The AF_UNIX socket */
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struct unix_sock {
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/* WARNING: sk has to be the first member */
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struct sock sk;
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struct unix_address *addr;
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struct path path;
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struct mutex iolock, bindlock;
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struct sock *peer;
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struct sock *listener;
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struct unix_vertex *vertex;
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spinlock_t lock;
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struct socket_wq peer_wq;
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wait_queue_entry_t peer_wake;
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struct scm_stat scm_stat;
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#if IS_ENABLED(CONFIG_AF_UNIX_OOB)
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struct sk_buff *oob_skb;
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#endif
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};
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#define unix_sk(ptr) container_of_const(ptr, struct unix_sock, sk)
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#define unix_peer(sk) (unix_sk(sk)->peer)
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#define unix_state_lock(s) spin_lock(&unix_sk(s)->lock)
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#define unix_state_unlock(s) spin_unlock(&unix_sk(s)->lock)
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enum unix_socket_lock_class {
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U_LOCK_NORMAL,
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U_LOCK_SECOND, /* for double locking, see unix_state_double_lock(). */
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U_LOCK_DIAG, /* used while dumping icons, see sk_diag_dump_icons(). */
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};
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static inline void unix_state_lock_nested(struct sock *sk,
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enum unix_socket_lock_class subclass)
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{
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spin_lock_nested(&unix_sk(sk)->lock, subclass);
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}
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#define peer_wait peer_wq.wait
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long unix_inq_len(struct sock *sk);
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long unix_outq_len(struct sock *sk);
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int __unix_dgram_recvmsg(struct sock *sk, struct msghdr *msg, size_t size,
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int flags);
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int __unix_stream_recvmsg(struct sock *sk, struct msghdr *msg, size_t size,
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int flags);
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#ifdef CONFIG_SYSCTL
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int unix_sysctl_register(struct net *net);
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void unix_sysctl_unregister(struct net *net);
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#else
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static inline int unix_sysctl_register(struct net *net) { return 0; }
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static inline void unix_sysctl_unregister(struct net *net) {}
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#endif
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#ifdef CONFIG_BPF_SYSCALL
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extern struct proto unix_dgram_proto;
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extern struct proto unix_stream_proto;
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int unix_dgram_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore);
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int unix_stream_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore);
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void __init unix_bpf_build_proto(void);
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#else
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static inline void __init unix_bpf_build_proto(void)
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{}
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#endif
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#endif
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