Re: [syzbot] [kernel?] KASAN: slab-use-after-free Read in reweight_entity

[Peter Zijlstra]

On Tue, Oct 17, 2023 at 07:58:56PM +0100, Dmitry Safonov wrote:
> FWIW,
> Managed to locally reproduce it twice on 58720809f527 (tag: v6.6-rc6)
> Linux 6.6-rc6 + TCP-AO patches on the top.
> (but can't reproduce reliably at will)
> 
> [dima@Mindolluin linux-tcp-ao]$ ./scripts/faddr2line vmlinux
> reweight_entity+0x3b0/0x490
> reweight_entity+0x3b0/0x490:

Could you please try:

  https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/commit/?h=sched/urgent&id=a3b75dce9d9ae4510ea75b655567f50622f48706


---
Subject: sched/eevdf: Fix heap corruption more
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Tue Oct 17 16:59:47 CEST 2023

Because someone is a flaming idiot... :/

Fixes: 8dafa9d0eb1a ("sched/eevdf: Fix min_deadline heap integrity")
Reported-by: 0599jiangyc@xxxxxxxxx
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=218020
---
 kernel/sched/fair.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3699,7 +3699,8 @@ static void reweight_entity(struct cfs_r
 		 */
 		deadline = div_s64(deadline * old_weight, weight);
 		se->deadline = se->vruntime + deadline;
-		min_deadline_cb_propagate(&se->run_node, NULL);
+		if (se != cfs_rq->curr)
+			min_deadline_cb_propagate(&se->run_node, NULL);
 	}
 
 #ifdef CONFIG_SMP