git: 28d08dc7d051 - main - clock_gettime: Fix CLOCK_THREAD_CPUTIME_ID race

From: Mark Johnston <markj_at_FreeBSD.org>
Date: Thu, 17 Mar 2022 19:40:14 UTC
The branch main has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=28d08dc7d051a4e058cc0004cf4dd884f87037a2

commit 28d08dc7d051a4e058cc0004cf4dd884f87037a2
Author:     firk <firk@cantconnect.ru>
AuthorDate: 2022-03-15 22:22:21 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2022-03-17 19:39:00 +0000

    clock_gettime: Fix CLOCK_THREAD_CPUTIME_ID race
    
    Use a spinlock section instead of a critical section to synchronize with
    statclock().  Otherwise the CLOCK_THREAD_CPUTIME_ID clock can appear to
    go backwards.
    
    PR:             262273
    Reviewed by:    markj
    MFC after:      1 week
    Differential Revision:  https://reviews.freebsd.org/D34568
---
 sys/kern/kern_time.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sys/kern/kern_time.c b/sys/kern/kern_time.c
index 74e7c42004ad..0bab05c65ffc 100644
--- a/sys/kern/kern_time.c
+++ b/sys/kern/kern_time.c
@@ -256,11 +256,11 @@ kern_thread_cputime(struct thread *targettd, struct timespec *ats)
 	uint64_t runtime, curtime, switchtime;
 
 	if (targettd == NULL) { /* current thread */
-		critical_enter();
+		spinlock_enter();
 		switchtime = PCPU_GET(switchtime);
 		curtime = cpu_ticks();
 		runtime = curthread->td_runtime;
-		critical_exit();
+		spinlock_exit();
 		runtime += curtime - switchtime;
 	} else {
 		PROC_LOCK_ASSERT(targettd->td_proc, MA_OWNED);