git: 56bc43f5d02b - main - locking.9: warn about using sleepable lock address as a sleep channel

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 which