Patch "sched/deadline: Initialize ->dl_boosted" has been added to the 4.19-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    sched/deadline: Initialize ->dl_boosted

to the 4.19-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     sched-deadline-initialize-dl_boosted.patch
and it can be found in the queue-4.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 3fcdde09b0dcb6d8169841765118d05859c8c79e
Author: Juri Lelli <juri.lelli@xxxxxxxxxx>
Date:   Wed Jun 17 09:29:19 2020 +0200

    sched/deadline: Initialize ->dl_boosted
    
    [ Upstream commit ce9bc3b27f2a21a7969b41ffb04df8cf61bd1592 ]
    
    syzbot reported the following warning triggered via SYSC_sched_setattr():
    
      WARNING: CPU: 0 PID: 6973 at kernel/sched/deadline.c:593 setup_new_dl_entity /kernel/sched/deadline.c:594 [inline]
      WARNING: CPU: 0 PID: 6973 at kernel/sched/deadline.c:593 enqueue_dl_entity /kernel/sched/deadline.c:1370 [inline]
      WARNING: CPU: 0 PID: 6973 at kernel/sched/deadline.c:593 enqueue_task_dl+0x1c17/0x2ba0 /kernel/sched/deadline.c:1441
    
    This happens because the ->dl_boosted flag is currently not initialized by
    __dl_clear_params() (unlike the other flags) and setup_new_dl_entity()
    rightfully complains about it.
    
    Initialize dl_boosted to 0.
    
    Fixes: 2d3d891d3344 ("sched/deadline: Add SCHED_DEADLINE inheritance logic")
    Reported-by: syzbot+5ac8bac25f95e8b221e7@xxxxxxxxxxxxxxxxxxxxxxxxx
    Signed-off-by: Juri Lelli <juri.lelli@xxxxxxxxxx>
    Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
    Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
    Tested-by: Daniel Wagner <dwagner@xxxxxxx>
    Link: https://lkml.kernel.org/r/20200617072919.818409-1-juri.lelli@xxxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index ebec37cb3be9a..8aecfb143859d 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -2688,6 +2688,7 @@ void __dl_clear_params(struct task_struct *p)
 	dl_se->dl_bw			= 0;
 	dl_se->dl_density		= 0;
 
+	dl_se->dl_boosted		= 0;
 	dl_se->dl_throttled		= 0;
 	dl_se->dl_yielded		= 0;
 	dl_se->dl_non_contending	= 0;