Date: Sun, 6 Apr 2014 20:00:42 +0000 (UTC) From: Ed Schouten <ed@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r264200 - head/sys/kern Message-ID: <201404062000.s36K0gOv060915@svn.freebsd.org>
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Author: ed Date: Sun Apr 6 20:00:42 2014 New Revision: 264200 URL: http://svnweb.freebsd.org/changeset/base/264200 Log: Nit: fix locking of p->p_state in procdesc_close(). According to <sys/proc.h>, this field needs to be locked with either the p_mtx or the p_slock. In this case the damage was quite small. Instead of being reaped, the process would just be reparented to init, so it could be reaped from there. Modified: head/sys/kern/sys_procdesc.c Modified: head/sys/kern/sys_procdesc.c ============================================================================== --- head/sys/kern/sys_procdesc.c Sun Apr 6 19:51:57 2014 (r264199) +++ head/sys/kern/sys_procdesc.c Sun Apr 6 20:00:42 2014 (r264200) @@ -364,39 +364,41 @@ procdesc_close(struct file *fp, struct t * collected and procdesc_reap() was already called. */ sx_xunlock(&proctree_lock); - } else if (p->p_state == PRS_ZOMBIE) { - /* - * If the process is already dead and just awaiting reaping, - * do that now. This will release the process's reference to - * the process descriptor when it calls back into - * procdesc_reap(). - */ - PROC_LOCK(p); - PROC_SLOCK(p); - proc_reap(curthread, p, NULL, 0); } else { - /* - * If the process is not yet dead, we need to kill it, but we - * can't wait around synchronously for it to go away, as that - * path leads to madness (and deadlocks). First, detach the - * process from its descriptor so that its exit status will - * be reported normally. - */ PROC_LOCK(p); - pd->pd_proc = NULL; - p->p_procdesc = NULL; - procdesc_free(pd); - - /* - * Next, reparent it to init(8) so that there's someone to - * pick up the pieces; finally, terminate with prejudice. - */ - p->p_sigparent = SIGCHLD; - proc_reparent(p, initproc); - if ((pd->pd_flags & PDF_DAEMON) == 0) - kern_psignal(p, SIGKILL); - PROC_UNLOCK(p); - sx_xunlock(&proctree_lock); + if (p->p_state == PRS_ZOMBIE) { + /* + * If the process is already dead and just awaiting + * reaping, do that now. This will release the + * process's reference to the process descriptor when it + * calls back into procdesc_reap(). + */ + PROC_SLOCK(p); + proc_reap(curthread, p, NULL, 0); + } else { + /* + * If the process is not yet dead, we need to kill it, + * but we can't wait around synchronously for it to go + * away, as that path leads to madness (and deadlocks). + * First, detach the process from its descriptor so that + * its exit status will be reported normally. + */ + pd->pd_proc = NULL; + p->p_procdesc = NULL; + procdesc_free(pd); + + /* + * Next, reparent it to init(8) so that there's someone + * to pick up the pieces; finally, terminate with + * prejudice. + */ + p->p_sigparent = SIGCHLD; + proc_reparent(p, initproc); + if ((pd->pd_flags & PDF_DAEMON) == 0) + kern_psignal(p, SIGKILL); + PROC_UNLOCK(p); + sx_xunlock(&proctree_lock); + } } /*
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