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Add send buffer locking to uipc_send(). Without this locking a race can

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occur between a reader and a writer that results in a panic upon close,
e.g.,
	"panic: sbflush_locked: cc 4 || mb 0xffffff0052afa400 || mbcnt 0"

Reviewed by: rwatson@
MFC after: 2 weeks
This commit is contained in:
Alan Cox 2004-12-22 20:28:46 +00:00
parent 84a8a1332e
commit 7abe2ac214
1 changed files with 3 additions and 0 deletions
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3
sys/kern/uipc_usrreq.c
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@ -452,7 +452,9 @@ uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
}
}
SOCKBUF_LOCK(&so->so_snd);
if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
SOCKBUF_UNLOCK(&so->so_snd);
error = EPIPE;
break;
}
@ -478,6 +480,7 @@ uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
(so2->so_rcv.sb_cc - unp->unp_conn->unp_cc);
(void)chgsbsize(so->so_cred->cr_uidinfo, &so->so_snd.sb_hiwat,
newhiwat, RLIM_INFINITY);
SOCKBUF_UNLOCK(&so->so_snd);
unp->unp_conn->unp_cc = so2->so_rcv.sb_cc;
sorwakeup_locked(so2);
m = NULL;