The branch stable/12 has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=71dfe98e34acdcb8b0f90880de28611e66662e91
commit 71dfe98e34acdcb8b0f90880de28611e66662e91 Author: Konstantin Belousov <[email protected]> AuthorDate: 2020-12-31 13:45:06 +0000 Commit: Konstantin Belousov <[email protected]> CommitDate: 2021-01-17 04:45:47 +0000 tty_wait_background: improve locking. (cherry picked from commit a008bdeda3b8278fe600cf83ecf44acd1ccb30b6) --- sys/kern/tty.c | 33 ++++++++++++++++++--------------- 1 file changed, 18 insertions(+), 15 deletions(-) diff --git a/sys/kern/tty.c b/sys/kern/tty.c index 63324ac3e881..693032908b3a 100644 --- a/sys/kern/tty.c +++ b/sys/kern/tty.c @@ -413,7 +413,7 @@ tty_is_ctty(struct tty *tp, struct proc *p) int tty_wait_background(struct tty *tp, struct thread *td, int sig) { - struct proc *p = td->td_proc; + struct proc *p; struct pgrp *pg; ksiginfo_t ksi; int error; @@ -421,8 +421,22 @@ tty_wait_background(struct tty *tp, struct thread *td, int sig) MPASS(sig == SIGTTIN || sig == SIGTTOU); tty_assert_locked(tp); + p = td->td_proc; for (;;) { + pg = p->p_pgrp; + PGRP_LOCK(pg); PROC_LOCK(p); + + /* + * pg may no longer be our process group. + * Re-check after locking. + */ + if (p->p_pgrp != pg) { + PROC_UNLOCK(p); + PGRP_UNLOCK(pg); + continue; + } + /* * The process should only sleep, when: * - This terminal is the controlling terminal @@ -435,6 +449,7 @@ tty_wait_background(struct tty *tp, struct thread *td, int sig) if (!tty_is_ctty(tp, p) || p->p_pgrp == tp->t_pgrp) { /* Allow the action to happen. */ PROC_UNLOCK(p); + PGRP_UNLOCK(pg); return (0); } @@ -442,13 +457,14 @@ tty_wait_background(struct tty *tp, struct thread *td, int sig) SIGISMEMBER(td->td_sigmask, sig)) { /* Only allow them in write()/ioctl(). */ PROC_UNLOCK(p); + PGRP_UNLOCK(pg); return (sig == SIGTTOU ? 0 : EIO); } - pg = p->p_pgrp; if ((p->p_flag & P_PPWAIT) != 0 || pg->pg_jobc == 0) { /* Don't allow the action to happen. */ PROC_UNLOCK(p); + PGRP_UNLOCK(pg); return (EIO); } PROC_UNLOCK(p); @@ -463,20 +479,7 @@ tty_wait_background(struct tty *tp, struct thread *td, int sig) ksi.ksi_signo = sig; sig = 0; } - PGRP_LOCK(pg); - - /* - * pg may no longer be our process group. - * Re-check after locking process group. - */ - PROC_LOCK(p); - if (p->p_pgrp != pg) { - PROC_UNLOCK(p); - PGRP_UNLOCK(pg); - continue; - } - PROC_UNLOCK(p); pgsignal(pg, ksi.ksi_signo, 1, &ksi); PGRP_UNLOCK(pg); _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/dev-commits-src-all To unsubscribe, send any mail to "[email protected]"
