The branch main has been updated by dchagin:
URL:
https://cgit.FreeBSD.org/src/commit/?id=2cd662064a0cd8d179cbb5a06378fce0ec458747
commit 2cd662064a0cd8d179cbb5a06378fce0ec458747
Author: Dmitry Chagin <dcha...@freebsd.org>
AuthorDate: 2022-05-19 16:52:18 +0000
Commit: Dmitry Chagin <dcha...@freebsd.org>
CommitDate: 2022-05-19 16:52:18 +0000
linux(4): Handle cas failure on ll/sc operations
Follow the 11a6ecd4. Check and handle the case when the ll/sc casu fails
even when the compare succeeds.
For more details PR/263825, https://reviews.freebsd.org/D35150.
Obtained from: Andrew@
MFC after: 2 weeks
---
sys/compat/linux/linux_futex.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/sys/compat/linux/linux_futex.c b/sys/compat/linux/linux_futex.c
index 6825d13e1aab..8bcdc378cf70 100644
--- a/sys/compat/linux/linux_futex.c
+++ b/sys/compat/linux/linux_futex.c
@@ -410,6 +410,17 @@ linux_futex_lock_pi(struct thread *td, bool try, struct
linux_futex_args *args)
break;
}
+ /*
+ * Nobody owns it, but the acquire failed. This can happen
+ * with ll/sc atomic.
+ */
+ if (owner == 0) {
+ error = thread_check_susp(td, true);
+ if (error != 0)
+ break;
+ continue;
+ }
+
/*
* Avoid overwriting a possible error from sleep due
* to the pending signal with suspension check result.
