diff options
| author | Konstantin Belousov <kib@FreeBSD.org> | 2026-05-15 11:05:45 +0000 |
|---|---|---|
| committer | Konstantin Belousov <kib@FreeBSD.org> | 2026-05-17 19:55:23 +0000 |
| commit | 56bc43f5d02bd0745d597db44c285bf78d083762 (patch) | |
| tree | a40cbf6168570b32bb5c84eb8780c9d6668d607f | |
| parent | 7bdf2b5d5fbabfc8749c4ff6e618c3e843b14de0 (diff) | |
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
| -rw-r--r-- | share/man/man9/locking.9 | 15 |
1 files 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 |