Merge subr_prof.c:1.119, 1.120, 1.121, nfs_socket.c:1.130,
rpcclnt.c:1.14 from HEAD to RELENG_6: Acquire Giant in uprintf() and tprintf() due to the non-MPSAFEty of the tty code invoked from these functions. In two cases, during timeout handling in NFS-related RPC client code, acquire Giant in the caller before other mutexes the caller might hold, in order to avoid lock order reversals with Giant (a recursive acquire is not a reversal as it won't ever wait). Correct age-old comments about uprintf()/tprintf() sleeping: they will never sleep. Much useful feedback from: bde Approved by: re (scottl)
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rwatson
parent
ebe24453ed
commit
5db6e492ee
@ -117,8 +117,6 @@ tablefull(const char *tab)
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/*
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* Uprintf prints to the controlling terminal for the current process.
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* It may block if the tty queue is overfull. No message is printed if
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* the queue does not clear in a reasonable time.
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*/
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int
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uprintf(const char *fmt, ...)
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@ -132,29 +130,34 @@ uprintf(const char *fmt, ...)
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if (td == NULL || td == PCPU_GET(idlethread))
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return (0);
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mtx_lock(&Giant);
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p = td->td_proc;
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PROC_LOCK(p);
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if ((p->p_flag & P_CONTROLT) == 0) {
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PROC_UNLOCK(p);
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return (0);
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retval = 0;
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goto out;
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}
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SESS_LOCK(p->p_session);
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pca.tty = p->p_session->s_ttyp;
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SESS_UNLOCK(p->p_session);
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PROC_UNLOCK(p);
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if (pca.tty == NULL)
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return (0);
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if (pca.tty == NULL) {
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retval = 0;
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goto out;
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}
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pca.flags = TOTTY;
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va_start(ap, fmt);
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retval = kvprintf(fmt, putchar, &pca, 10, ap);
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va_end(ap);
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out:
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mtx_unlock(&Giant);
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return (retval);
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}
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/*
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* tprintf prints on the controlling terminal associated
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* with the given session, possibly to the log as well.
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* tprintf prints on the controlling terminal associated with the given
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* session, possibly to the log as well.
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*/
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void
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tprintf(struct proc *p, int pri, const char *fmt, ...)
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@ -165,6 +168,7 @@ tprintf(struct proc *p, int pri, const char *fmt, ...)
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struct putchar_arg pca;
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struct session *sess = NULL;
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mtx_lock(&Giant);
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if (pri != -1)
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flags |= TOLOG;
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if (p != NULL) {
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@ -192,6 +196,7 @@ tprintf(struct proc *p, int pri, const char *fmt, ...)
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if (sess != NULL)
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SESSRELE(sess);
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msgbuftrigger = 1;
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mtx_unlock(&Giant);
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}
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/*
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@ -1048,8 +1048,11 @@ nfs_request(struct vnode *vp, struct mbuf *mrest, int procnum,
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* If there was a successful reply and a tprintf msg.
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* tprintf a response.
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*/
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if (!error)
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if (!error) {
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mtx_lock(&Giant);
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nfs_up(rep, nmp, rep->r_td, "is alive again", NFSSTA_TIMEO);
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mtx_unlock(&Giant);
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}
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mrep = rep->r_mrep;
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md = rep->r_md;
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dpos = rep->r_dpos;
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@ -1178,6 +1181,7 @@ nfs_timer(void *arg)
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getmicrouptime(&now);
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s = splnet();
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mtx_lock(&Giant); /* nfs_down -> tprintf */
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mtx_lock(&nfs_reqq_mtx);
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TAILQ_FOREACH(rep, &nfs_reqq, r_chain) {
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nmp = rep->r_nmp;
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@ -1281,6 +1285,7 @@ nfs_timer(void *arg)
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}
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}
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mtx_unlock(&nfs_reqq_mtx);
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mtx_unlock(&Giant); /* nfs_down -> tprintf */
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splx(s);
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callout_reset(&nfs_callout, nfs_ticks, nfs_timer, NULL);
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}
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@ -1612,6 +1617,8 @@ nfs_msg(struct thread *td, const char *server, const char *msg, int error)
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{
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struct proc *p;
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GIANT_REQUIRED; /* tprintf */
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p = td ? td->td_proc : NULL;
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if (error) {
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tprintf(p, LOG_INFO, "nfs server %s: %s, error %d\n", server,
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@ -1631,6 +1638,8 @@ nfs_down(rep, nmp, td, msg, error, flags)
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int error, flags;
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{
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GIANT_REQUIRED; /* nfs_msg */
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if (nmp == NULL)
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return;
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if ((flags & NFSSTA_TIMEO) && !(nmp->nm_state & NFSSTA_TIMEO)) {
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@ -1658,6 +1667,9 @@ nfs_up(rep, nmp, td, msg, flags)
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const char *msg;
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int flags;
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{
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GIANT_REQUIRED; /* nfs_msg */
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if (nmp == NULL)
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return;
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if ((rep == NULL) || (rep->r_flags & R_TPRINTFMSG) != 0)
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@ -1254,9 +1254,12 @@ rpcclnt_request(rpc, mrest, procnum, td, cred, reply)
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* If there was a successful reply and a tprintf msg. tprintf a
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* response.
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*/
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if (!error && (task->r_flags & R_TPRINTFMSG))
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if (!error && (task->r_flags & R_TPRINTFMSG)) {
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mtx_lock(&Giant);
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rpcclnt_msg(task->r_td, rpc->rc_prog->prog_name,
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"is alive again");
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mtx_unlock(&Giant);
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}
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/* free request header (leaving mrest) */
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mheadend->m_next = NULL;
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@ -1390,6 +1393,7 @@ rpcclnt_timer(arg)
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#else
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s = splnet();
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#endif
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mtx_lock(&Giant); /* rpc_msg -> tprintf */
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TAILQ_FOREACH(rep, &rpctask_q, r_chain) {
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rpc = rep->r_rpcclnt;
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if (rep->r_mrep || (rep->r_flags & R_SOFTTERM))
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@ -1474,6 +1478,7 @@ rpcclnt_timer(arg)
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}
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}
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}
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mtx_unlock(&Giant); /* rpc_msg -> tprintf */
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splx(s);
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#ifdef __OpenBSD__
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@ -1775,6 +1780,8 @@ rpcclnt_msg(p, server, msg)
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tprintf_close(tpr);
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RPC_RETURN(0);
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#else
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GIANT_REQUIRED;
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tprintf(p ? p->td_proc : NULL, LOG_INFO,
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"nfs server %s: %s\n", server, msg);
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RPC_RETURN(0);
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