Date: Tue, 26 Feb 2013 21:05:07 +0000 (UTC) From: John Baldwin <jhb@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-8@freebsd.org Subject: svn commit: r247350 - stable/8/sys/kern Message-ID: <201302262105.r1QL57aS062861@svn.freebsd.org>
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Author: jhb Date: Tue Feb 26 21:05:06 2013 New Revision: 247350 URL: http://svnweb.freebsd.org/changeset/base/247350 Log: MFC 240467: Ignore stop and continue signals sent to an exiting process. Stop signals set p_xstat to the signal that triggered the stop, but p_xstat is also used to hold the exit status of an exiting process. Without this change, a stop signal that arrived after a process was marked P_WEXIT but before it was marked a zombie would overwrite the exit status with the stop signal number. Modified: stable/8/sys/kern/kern_exit.c stable/8/sys/kern/kern_sig.c Directory Properties: stable/8/sys/ (props changed) stable/8/sys/kern/ (props changed) Modified: stable/8/sys/kern/kern_exit.c ============================================================================== --- stable/8/sys/kern/kern_exit.c Tue Feb 26 21:04:58 2013 (r247349) +++ stable/8/sys/kern/kern_exit.c Tue Feb 26 21:05:06 2013 (r247350) @@ -183,6 +183,14 @@ exit1(struct thread *td, int rv) _STOPEVENT(p, S_EXIT, rv); /* + * Ignore any pending request to stop due to a stop signal. + * Once P_WEXIT is set, future requests will be ignored as + * well. + */ + p->p_flag &= ~P_STOPPED_SIG; + KASSERT(!P_SHOULDSTOP(p), ("exiting process is stopped")); + + /* * Note that we are exiting and do another wakeup of anyone in * PIOCWAIT in case they aren't listening for S_EXIT stops or * decided to wait again after we told them we are exiting. Modified: stable/8/sys/kern/kern_sig.c ============================================================================== --- stable/8/sys/kern/kern_sig.c Tue Feb 26 21:04:58 2013 (r247349) +++ stable/8/sys/kern/kern_sig.c Tue Feb 26 21:05:06 2013 (r247350) @@ -2142,6 +2142,8 @@ tdsignal(struct proc *p, struct thread * * We try do the per-process part here. */ if (P_SHOULDSTOP(p)) { + KASSERT(!(p->p_flag & P_WEXIT), + ("signal to stopped but exiting process")); if (sig == SIGKILL) { /* * If traced process is already stopped, @@ -2256,7 +2258,7 @@ tdsignal(struct proc *p, struct thread * MPASS(action == SIG_DFL); if (prop & SA_STOP) { - if (p->p_flag & P_PPWAIT) + if (p->p_flag & (P_PPWAIT|P_WEXIT)) goto out; p->p_flag |= P_STOPPED_SIG; p->p_xstat = sig; @@ -2418,6 +2420,7 @@ ptracestop(struct thread *td, int sig) struct proc *p = td->td_proc; PROC_LOCK_ASSERT(p, MA_OWNED); + KASSERT(!(p->p_flag & P_WEXIT), ("Stopping exiting process")); WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, &p->p_mtx.lock_object, "Stopping for traced signal"); @@ -2658,7 +2661,7 @@ issignal(struct thread *td, int stop_all * process group, ignore tty stop signals. */ if (prop & SA_STOP) { - if (p->p_flag & P_TRACED || + if (p->p_flag & (P_TRACED|P_WEXIT) || (p->p_pgrp->pg_jobc == 0 && prop & SA_TTYSTOP)) break; /* == ignore */
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