On Tue, Jun 01, 2021 at 12:44:30PM +0000, Dmitry Chagin wrote: > On Thu, May 27, 2021 at 07:53:23PM +0000, Mark Johnston wrote: > > The branch main has been updated by markj: > > > > URL: > > https://cgit.FreeBSD.org/src/commit/?id=f3851b235b23d9220ace31bbc89b1fe0a78fc75c > > > > commit f3851b235b23d9220ace31bbc89b1fe0a78fc75c > > Author: Mark Johnston <[email protected]> > > AuthorDate: 2021-05-27 19:49:59 +0000 > > Commit: Mark Johnston <[email protected]> > > CommitDate: 2021-05-27 19:52:20 +0000 > > > > ktrace: Fix a race with fork() > > > > ktrace(2) may toggle trace points in any of > > 1. a single process > > 2. all members of a process group > > 3. all descendents of the processes in 1 or 2 > > > > In the first two cases, we do not permit the operation if the process is > > being forked or not visible. However, in case 3 we did not enforce this > > restriction for descendents. As a result, the assertions about the child > > in ktrprocfork() may be violated. > > > > Move these checks into ktrops() so that they are applied consistently. > > > > Allow KTROP_CLEAR for nascent processes. Otherwise, there is a window > > where we cannot clear trace points for a nascent child if they are > > inherited from the parent. > > > > Reported by: [email protected] > > Reported by: [email protected] > > Reviewed by: kib > > MFC after: 1 week > > Sponsored by: The FreeBSD Foundation > > Differential Revision: https://reviews.freebsd.org/D30481 > > --- > > sys/kern/kern_ktrace.c | 43 ++++++++++++++++++++++--------------------- > > 1 file changed, 22 insertions(+), 21 deletions(-) > > > > diff --git a/sys/kern/kern_ktrace.c b/sys/kern/kern_ktrace.c > > index dc064d9ebd67..4a2dad20b035 100644 > > --- a/sys/kern/kern_ktrace.c > > +++ b/sys/kern/kern_ktrace.c > > @@ -1006,7 +1006,7 @@ sys_ktrace(struct thread *td, struct ktrace_args *uap) > > int facs = uap->facs & ~KTRFAC_ROOT; > > int ops = KTROP(uap->ops); > > int descend = uap->ops & KTRFLAG_DESCEND; > > - int nfound, ret = 0; > > + int ret = 0; > > int flags, error = 0; > > struct nameidata nd; > > struct ktr_io_params *kiop, *old_kiop; > > @@ -1080,42 +1080,31 @@ restart: > > error = ESRCH; > > goto done; > > } > > + > > /* > > * ktrops() may call vrele(). Lock pg_members > > * by the proctree_lock rather than pg_mtx. > > */ > > PGRP_UNLOCK(pg); > > - nfound = 0; > > + if (LIST_EMPTY(&pg->pg_members)) { > > + sx_sunlock(&proctree_lock); > > + error = ESRCH; > > + goto done; > > + } > > LIST_FOREACH(p, &pg->pg_members, p_pglist) { > > PROC_LOCK(p); > > - if (p->p_state == PRS_NEW || > > - p_cansee(td, p) != 0) { > > - PROC_UNLOCK(p); > > - continue; > > - } > > - nfound++; > > if (descend) > > ret |= ktrsetchildren(td, p, ops, facs, kiop); > > else > > ret |= ktrops(td, p, ops, facs, kiop); > > } > > - if (nfound == 0) { > > - sx_sunlock(&proctree_lock); > > - error = ESRCH; > > - goto done; > > - } > > } else { > > /* > > * by pid > > */ > > p = pfind(uap->pid); > > - if (p == NULL) > > + if (p == NULL) { > > error = ESRCH; > > - else > > - error = p_cansee(td, p); > > - if (error) { > > - if (p != NULL) > > - PROC_UNLOCK(p); > > sx_sunlock(&proctree_lock); > > goto done; > > } > > @@ -1187,8 +1176,20 @@ ktrops(struct thread *td, struct proc *p, int ops, > > int facs, > > PROC_UNLOCK(p); > > return (0); > > } > > - if (p->p_flag & P_WEXIT) { > > - /* If the process is exiting, just ignore it. */ > > + if ((ops == KTROP_SET && p->p_state == PRS_NEW) || !p_cansee(td, p)) { > > ^^^^^^^^^^^^^^ seems that it broke ktrace: > root@mordor:~ # ktrace ls > ktrace: ktrace.out: Operation not permitted
Indeed, I pushed a fix to main. Sorry for the breakage. _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/dev-commits-src-all To unsubscribe, send any mail to "[email protected]"
