Date: Sun, 17 May 2026 19:56:15 +0000 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: 56bc43f5d02b - main - locking.9: warn about using sleepable lock address as a sleep channel Message-ID: <6a0a1d5f.31478.7a5c2aa@gitrepo.freebsd.org>
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The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=56bc43f5d02bd0745d597db44c285bf78d083762 commit 56bc43f5d02bd0745d597db44c285bf78d083762 Author: Konstantin Belousov <kib@FreeBSD.org> AuthorDate: 2026-05-15 11:05:45 +0000 Commit: Konstantin Belousov <kib@FreeBSD.org> CommitDate: 2026-05-17 19:55:23 +0000 locking.9: warn about using sleepable lock address as a sleep channel Reviewed by: markj Sponsored by: The FreeBSD Foundation MFC after: 3 days Differential revision: https://reviews.freebsd.org/D57012 --- share/man/man9/locking.9 | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/share/man/man9/locking.9 b/share/man/man9/locking.9 index ad044b6e1d46..9afdcd56f4f6 100644 --- a/share/man/man9/locking.9 +++ b/share/man/man9/locking.9 @@ -205,11 +205,6 @@ The functions and .Fn wakeup_one also handle event-based thread blocking. -Unlike condition variables, -arbitrary addresses may be used as wait channels and a dedicated -structure does not need to be allocated. -However, care must be taken to ensure that wait channel addresses are -unique to an event. If a thread must wait for an external event, it is put to sleep by .Fn tsleep , .Fn msleep , @@ -222,6 +217,16 @@ Threads may also wait using one of the locking primitive sleep routines or .Xr sx_sleep 9 . .Pp +Unlike condition variables, +arbitrary addresses may be used as wait channels and a dedicated +structure does not need to be allocated. +However, care must be taken to ensure that wait channel addresses are +unique to an event. +For example, the memory address of a sleepable lock such as a +.Xr sx 9 +must not be used as a sleep channel, because the lock implementation +will internally use the same address as a wait channel. +.Pp The parameter .Fa chan is an arbitrary address that uniquely identifies the event on whichhome | help
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