From: Karel Zak <kzak@redhat.com>
Date: Thu, 1 Oct 2020 08:40:27 +0000 (+0200)
Subject: chrt: use SCHED_FLAG_RESET_ON_FORK for sched_setattr()
X-Git-Tag: v2.37-rc1~450
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=240634f80caf99590c4acdb432d9db7cbb8902df;p=thirdparty%2Futil-linux.git

chrt: use SCHED_FLAG_RESET_ON_FORK for sched_setattr()

Reviewed by many people, used for years (but probably nobody uses
SCHED_DEADLINE with reset-on-fork), but we all missed:

- sched_setscheduler() uses SCHED_RESET_ON_FORK (0x40000000)
- sched_setattr() uses SCHED_FLAG_RESET_ON_FORK (0x01)

Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=1883013
Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/schedutils/chrt.c b/schedutils/chrt.c
index 299c99221e..dbc630fc1f 100644
--- a/schedutils/chrt.c
+++ b/schedutils/chrt.c
@@ -123,7 +123,7 @@ struct chrt_ctl {
 	uint64_t period;
 
 	unsigned int all_tasks : 1,		/* all threads of the PID */
-		     reset_on_fork : 1,		/* SCHED_RESET_ON_FORK */
+		     reset_on_fork : 1,		/* SCHED_RESET_ON_FORK or SCHED_FLAG_RESET_ON_FORK */
 		     altered : 1,		/* sched_set**() used */
 		     verbose : 1;		/* verbose output */
 };
@@ -385,9 +385,10 @@ static int set_sched_one(struct chrt_ctl *ctl, pid_t pid)
 	sa.sched_period   = ctl->period;
 	sa.sched_deadline = ctl->deadline;
 
-# ifdef SCHED_RESET_ON_FORK
+# ifdef SCHED_FLAG_RESET_ON_FORK
+	/* Don't use SCHED_RESET_ON_FORK for sched_setattr()! */
 	if (ctl->reset_on_fork)
-		sa.sched_flags |= SCHED_RESET_ON_FORK;
+		sa.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
 # endif
 	errno = 0;
 	return sched_setattr(pid, &sa, 0);