Date: Wed, 5 Nov 2025 00:28:13 GMT From: Kyle Evans <kevans@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 90314c04f10f - main - makedev(9): drop an additional note about cdevpriv dtors Message-ID: <202511050028.5A50SDZM017305@gitrepo.freebsd.org>
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The branch main has been updated by kevans: URL: https://cgit.FreeBSD.org/src/commit/?id=90314c04f10f583c37c59ec51fd628e3deaf3622 commit 90314c04f10f583c37c59ec51fd628e3deaf3622 Author: Kyle Evans <kevans@FreeBSD.org> AuthorDate: 2025-11-05 00:28:02 +0000 Commit: Kyle Evans <kevans@FreeBSD.org> CommitDate: 2025-11-05 00:28:02 +0000 makedev(9): drop an additional note about cdevpriv dtors These were previously somewhat safe to call destroy_dev(9), but will now also cause a deadlock in the same fashion that d_close doing so would previously. Amend the note to point it out, in case it's useful for someone. Reviewed by: imp, kib, markj Differential Revision: https://reviews.freebsd.org/D53439 --- share/man/man9/make_dev.9 | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/share/man/man9/make_dev.9 b/share/man/man9/make_dev.9 index de56f350faa5..9f2c36fb39a4 100644 --- a/share/man/man9/make_dev.9 +++ b/share/man/man9/make_dev.9 @@ -25,7 +25,7 @@ .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" -.Dd January 19, 2025 +.Dd November 4, 2025 .Dt MAKE_DEV 9 .Os .Sh NAME @@ -387,14 +387,18 @@ function is the same as: destroy_dev_sched_cb(cdev, NULL, NULL); .Ed .Pp -The +Neither the .Fn d_close -driver method cannot call +driver method, nor a +.Xr devfs_cdevpriv 9 +.Fa dtr +method can .Fn destroy_dev directly. Doing so causes deadlock when .Fn destroy_dev -waits for all threads to leave the driver methods. +waits for all threads to leave the driver methods and finish executing any +per-open destructors. Also, because .Fn destroy_dev sleeps, no non-sleepable locks may be held over the call.help
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