Date: Tue, 18 May 2021 18:05:13 GMT From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 8cf912b017a0 - main - ttydev_write: prevent stops while terminal is busied Message-ID: <202105181805.14II5DTG017576@gitrepo.freebsd.org>
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The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=8cf912b017a04a2eec01fbaa1f7b9ef556403ede commit 8cf912b017a04a2eec01fbaa1f7b9ef556403ede Author: Konstantin Belousov <kib@FreeBSD.org> AuthorDate: 2021-05-13 01:35:06 +0000 Commit: Konstantin Belousov <kib@FreeBSD.org> CommitDate: 2021-05-18 17:52:03 +0000 ttydev_write: prevent stops while terminal is busied Since busy state is checked by all blocked writes, stopping a process which waits in ttydisc_write() causes cascade. Utilize sigdeferstop() to avoid the issue. Submitted by: Jakub Piecuch <j.piecuch96@gmail.com> PR: 255816 MFC after: 1 week --- sys/kern/tty.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/sys/kern/tty.c b/sys/kern/tty.c index 00b4df675311..8700eb8f9ef1 100644 --- a/sys/kern/tty.c +++ b/sys/kern/tty.c @@ -525,7 +525,7 @@ static int ttydev_write(struct cdev *dev, struct uio *uio, int ioflag) { struct tty *tp = dev->si_drv1; - int error; + int defer, error; error = ttydev_enter(tp); if (error) @@ -549,7 +549,9 @@ ttydev_write(struct cdev *dev, struct uio *uio, int ioflag) } tp->t_flags |= TF_BUSY_OUT; + defer = sigdeferstop(SIGDEFERSTOP_ERESTART); error = ttydisc_write(tp, uio, ioflag); + sigallowstop(defer); tp->t_flags &= ~TF_BUSY_OUT; cv_signal(&tp->t_outserwait); }
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