From: Jiayuan Chen When CONFIG_PREEMPT_RT is enabled, __SPIN_LOCK_UNLOCKED() expands to a brace-enclosed initializer rather than a compound literal, which cannot be used in assignment expressions. This causes a build failure: net/core/sock.c:3787:29: error: expected expression before '{' token 3787 | tmp.slock = __SPIN_LOCK_UNLOCKED(tmp.slock); Use declaration-with-initializer instead of assignment, consistent with how __SPIN_LOCK_UNLOCKED() is used elsewhere in the kernel (e.g. DEFINE_SPINLOCK). Fixes: 5151ec54f586 ("net: use try_cmpxchg() in lock_sock_nested()") Suggested-by: Eric Dumazet Signed-off-by: Jiayuan Chen --- net/core/sock.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/net/core/sock.c b/net/core/sock.c index 9d841975a7a1..fba4d5b8553c 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -3782,12 +3782,15 @@ void noinline lock_sock_nested(struct sock *sk, int subclass) might_sleep(); #ifdef CONFIG_64BIT if (sizeof(struct slock_owned) == sizeof(long)) { - socket_lock_t tmp, old; + socket_lock_t tmp = { + .slock = __SPIN_LOCK_UNLOCKED(tmp.slock), + .owned = 1, + }; + socket_lock_t old = { + .slock = __SPIN_LOCK_UNLOCKED(old.slock), + .owned = 0, + }; - tmp.slock = __SPIN_LOCK_UNLOCKED(tmp.slock); - tmp.owned = 1; - old.slock = __SPIN_LOCK_UNLOCKED(old.slock); - old.owned = 0; if (likely(try_cmpxchg(&sk->sk_lock.combined, &old.combined, tmp.combined))) return; -- 2.43.0