Proc locking. Lock around psignal() and also ensure both an exclusive
proctree lock and the process lock are held when updating p_pptr and p_oppid. When we are just reaading p_pptr we only need the proc lock and not a proctree lock as well.
This commit is contained in:
John Baldwin
parent
731a1aea4c
commit
c65c565b44
@ -125,13 +125,21 @@ procfs_control(curp, p, op)
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* by the calling process.
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*/
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if (op == PROCFS_CTL_ATTACH) {
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PROCTREE_LOCK(PT_EXCLUSIVE);
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PROC_LOCK(p);
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/* check whether already being traced */
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if (p->p_flag & P_TRACED)
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if (p->p_flag & P_TRACED) {
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PROC_UNLOCK(p);
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PROCTREE_LOCK(PT_RELEASE);
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return (EBUSY);
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}
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/* can't trace yourself! */
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if (p->p_pid == curp->p_pid)
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if (p->p_pid == curp->p_pid) {
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PROC_UNLOCK(p);
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PROCTREE_LOCK(PT_RELEASE);
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return (EINVAL);
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}
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/*
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* Go ahead and set the trace flag.
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@ -144,13 +152,13 @@ procfs_control(curp, p, op)
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p->p_flag |= P_TRACED;
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faultin(p);
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p->p_xstat = 0; /* XXX ? */
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PROCTREE_LOCK(PT_EXCLUSIVE);
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if (p->p_pptr != curp) {
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p->p_oppid = p->p_pptr->p_pid;
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proc_reparent(p, curp);
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}
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PROCTREE_LOCK(PT_RELEASE);
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psignal(p, SIGSTOP);
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PROC_UNLOCK(p);
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PROCTREE_LOCK(PT_RELEASE);
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return (0);
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}
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@ -166,15 +174,15 @@ procfs_control(curp, p, op)
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break;
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default:
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PROCTREE_LOCK(PT_SHARED);
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PROC_LOCK(p);
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mtx_lock_spin(&sched_lock);
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if (!TRACE_WAIT_P(curp, p)) {
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mtx_unlock_spin(&sched_lock);
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PROCTREE_LOCK(PT_RELEASE);
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PROC_UNLOCK(p);
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return (EBUSY);
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}
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mtx_unlock_spin(&sched_lock);
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PROCTREE_LOCK(PT_RELEASE);
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PROC_UNLOCK(p);
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}
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@ -190,6 +198,7 @@ procfs_control(curp, p, op)
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* To continue with a signal, just send
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* the signal name to the ctl file
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*/
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PROC_LOCK(p);
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p->p_xstat = 0;
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switch (op) {
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@ -199,14 +208,17 @@ procfs_control(curp, p, op)
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*/
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case PROCFS_CTL_DETACH:
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/* if not being traced, then this is a painless no-op */
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if ((p->p_flag & P_TRACED) == 0)
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if ((p->p_flag & P_TRACED) == 0) {
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PROC_UNLOCK(p);
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return (0);
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}
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/* not being traced any more */
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p->p_flag &= ~P_TRACED;
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/* remove pending SIGTRAP, else the process will die */
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SIGDELSET(p->p_siglist, SIGTRAP);
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PROC_UNLOCK(p);
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/* give process back to original parent */
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PROCTREE_LOCK(PT_EXCLUSIVE);
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@ -214,13 +226,16 @@ procfs_control(curp, p, op)
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struct proc *pp;
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pp = pfind(p->p_oppid);
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PROC_LOCK(p);
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if (pp)
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proc_reparent(p, pp);
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}
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PROCTREE_LOCK(PT_RELEASE);
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} else
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PROC_LOCK(p);
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p->p_oppid = 0;
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p->p_flag &= ~P_WAITED; /* XXX ? */
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PROC_UNLOCK(p);
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PROCTREE_LOCK(PT_RELEASE);
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wakeup((caddr_t) curp); /* XXX for CTL_WAIT below ? */
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break;
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@ -229,7 +244,8 @@ procfs_control(curp, p, op)
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* Step. Let the target process execute a single instruction.
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*/
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case PROCFS_CTL_STEP:
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PHOLD(p);
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_PHOLD(p);
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PROC_UNLOCK(p);
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error = procfs_sstep(p);
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PRELE(p);
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if (error)
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@ -241,6 +257,7 @@ procfs_control(curp, p, op)
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* or some other trap.
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*/
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case PROCFS_CTL_RUN:
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PROC_UNLOCK(p);
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break;
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/*
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@ -251,24 +268,22 @@ procfs_control(curp, p, op)
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case PROCFS_CTL_WAIT:
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error = 0;
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if (p->p_flag & P_TRACED) {
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PROCTREE_LOCK(PT_SHARED);
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mtx_lock_spin(&sched_lock);
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while (error == 0 &&
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(p->p_stat != SSTOP) &&
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(p->p_flag & P_TRACED) &&
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(p->p_pptr == curp)) {
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mtx_unlock_spin(&sched_lock);
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PROCTREE_LOCK(PT_RELEASE);
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error = tsleep((caddr_t) p,
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error = msleep((caddr_t) p, &p->p_mtx,
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PWAIT|PCATCH, "procfsx", 0);
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PROCTREE_LOCK(PT_SHARED);
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mtx_lock_spin(&sched_lock);
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}
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if (error == 0 && !TRACE_WAIT_P(curp, p))
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error = EBUSY;
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mtx_unlock_spin(&sched_lock);
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PROCTREE_LOCK(PT_RELEASE);
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PROC_UNLOCK(p);
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} else {
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PROC_UNLOCK(p);
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mtx_lock_spin(&sched_lock);
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while (error == 0 && p->p_stat != SSTOP) {
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mtx_unlock_spin(&sched_lock);
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@ -328,7 +343,7 @@ procfs_doctl(curp, p, pfs, uio)
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} else {
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nm = vfs_findname(signames, msg, xlen);
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if (nm) {
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PROCTREE_LOCK(PT_SHARED);
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PROC_LOCK(p);
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mtx_lock_spin(&sched_lock);
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if (TRACE_WAIT_P(curp, p)) {
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p->p_xstat = nm->nm_val;
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@ -337,12 +352,11 @@ procfs_doctl(curp, p, pfs, uio)
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#endif
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setrunnable(p);
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mtx_unlock_spin(&sched_lock);
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PROCTREE_LOCK(PT_RELEASE);
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} else {
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mtx_unlock_spin(&sched_lock);
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PROCTREE_LOCK(PT_RELEASE);
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psignal(p, nm->nm_val);
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}
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PROC_UNLOCK(p);
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error = 0;
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}
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}
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@ -125,13 +125,21 @@ procfs_control(curp, p, op)
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* by the calling process.
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*/
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if (op == PROCFS_CTL_ATTACH) {
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PROCTREE_LOCK(PT_EXCLUSIVE);
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PROC_LOCK(p);
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/* check whether already being traced */
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if (p->p_flag & P_TRACED)
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if (p->p_flag & P_TRACED) {
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PROC_UNLOCK(p);
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PROCTREE_LOCK(PT_RELEASE);
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return (EBUSY);
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}
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/* can't trace yourself! */
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if (p->p_pid == curp->p_pid)
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if (p->p_pid == curp->p_pid) {
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PROC_UNLOCK(p);
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PROCTREE_LOCK(PT_RELEASE);
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return (EINVAL);
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}
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/*
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* Go ahead and set the trace flag.
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@ -144,13 +152,13 @@ procfs_control(curp, p, op)
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p->p_flag |= P_TRACED;
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faultin(p);
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p->p_xstat = 0; /* XXX ? */
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PROCTREE_LOCK(PT_EXCLUSIVE);
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if (p->p_pptr != curp) {
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p->p_oppid = p->p_pptr->p_pid;
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proc_reparent(p, curp);
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}
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PROCTREE_LOCK(PT_RELEASE);
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psignal(p, SIGSTOP);
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PROC_UNLOCK(p);
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PROCTREE_LOCK(PT_RELEASE);
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return (0);
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}
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@ -166,15 +174,15 @@ procfs_control(curp, p, op)
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break;
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default:
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PROCTREE_LOCK(PT_SHARED);
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PROC_LOCK(p);
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mtx_lock_spin(&sched_lock);
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if (!TRACE_WAIT_P(curp, p)) {
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mtx_unlock_spin(&sched_lock);
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PROCTREE_LOCK(PT_RELEASE);
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PROC_UNLOCK(p);
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return (EBUSY);
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}
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mtx_unlock_spin(&sched_lock);
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PROCTREE_LOCK(PT_RELEASE);
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PROC_UNLOCK(p);
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}
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@ -190,6 +198,7 @@ procfs_control(curp, p, op)
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* To continue with a signal, just send
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* the signal name to the ctl file
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*/
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PROC_LOCK(p);
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p->p_xstat = 0;
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switch (op) {
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@ -199,14 +208,17 @@ procfs_control(curp, p, op)
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*/
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case PROCFS_CTL_DETACH:
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/* if not being traced, then this is a painless no-op */
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if ((p->p_flag & P_TRACED) == 0)
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if ((p->p_flag & P_TRACED) == 0) {
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PROC_UNLOCK(p);
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return (0);
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}
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/* not being traced any more */
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p->p_flag &= ~P_TRACED;
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/* remove pending SIGTRAP, else the process will die */
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SIGDELSET(p->p_siglist, SIGTRAP);
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PROC_UNLOCK(p);
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/* give process back to original parent */
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PROCTREE_LOCK(PT_EXCLUSIVE);
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@ -214,13 +226,16 @@ procfs_control(curp, p, op)
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struct proc *pp;
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pp = pfind(p->p_oppid);
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PROC_LOCK(p);
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if (pp)
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proc_reparent(p, pp);
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}
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PROCTREE_LOCK(PT_RELEASE);
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} else
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PROC_LOCK(p);
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p->p_oppid = 0;
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p->p_flag &= ~P_WAITED; /* XXX ? */
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PROC_UNLOCK(p);
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PROCTREE_LOCK(PT_RELEASE);
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wakeup((caddr_t) curp); /* XXX for CTL_WAIT below ? */
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break;
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@ -229,7 +244,8 @@ procfs_control(curp, p, op)
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* Step. Let the target process execute a single instruction.
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*/
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case PROCFS_CTL_STEP:
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PHOLD(p);
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_PHOLD(p);
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PROC_UNLOCK(p);
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error = procfs_sstep(p);
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PRELE(p);
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if (error)
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@ -241,6 +257,7 @@ procfs_control(curp, p, op)
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* or some other trap.
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*/
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case PROCFS_CTL_RUN:
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PROC_UNLOCK(p);
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break;
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/*
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@ -251,24 +268,22 @@ procfs_control(curp, p, op)
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case PROCFS_CTL_WAIT:
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error = 0;
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if (p->p_flag & P_TRACED) {
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PROCTREE_LOCK(PT_SHARED);
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mtx_lock_spin(&sched_lock);
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while (error == 0 &&
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(p->p_stat != SSTOP) &&
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(p->p_flag & P_TRACED) &&
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(p->p_pptr == curp)) {
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mtx_unlock_spin(&sched_lock);
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PROCTREE_LOCK(PT_RELEASE);
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error = tsleep((caddr_t) p,
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error = msleep((caddr_t) p, &p->p_mtx,
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PWAIT|PCATCH, "procfsx", 0);
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PROCTREE_LOCK(PT_SHARED);
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mtx_lock_spin(&sched_lock);
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}
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if (error == 0 && !TRACE_WAIT_P(curp, p))
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error = EBUSY;
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mtx_unlock_spin(&sched_lock);
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PROCTREE_LOCK(PT_RELEASE);
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PROC_UNLOCK(p);
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} else {
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PROC_UNLOCK(p);
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mtx_lock_spin(&sched_lock);
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while (error == 0 && p->p_stat != SSTOP) {
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mtx_unlock_spin(&sched_lock);
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@ -328,7 +343,7 @@ procfs_doctl(curp, p, pfs, uio)
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} else {
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nm = vfs_findname(signames, msg, xlen);
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if (nm) {
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PROCTREE_LOCK(PT_SHARED);
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PROC_LOCK(p);
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mtx_lock_spin(&sched_lock);
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if (TRACE_WAIT_P(curp, p)) {
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p->p_xstat = nm->nm_val;
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@ -337,12 +352,11 @@ procfs_doctl(curp, p, pfs, uio)
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#endif
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setrunnable(p);
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mtx_unlock_spin(&sched_lock);
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PROCTREE_LOCK(PT_RELEASE);
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} else {
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mtx_unlock_spin(&sched_lock);
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PROCTREE_LOCK(PT_RELEASE);
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psignal(p, nm->nm_val);
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}
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PROC_UNLOCK(p);
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error = 0;
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}
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}
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