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From:   dann frazier <dann.frazier@canonical.com>
To:     stable@vger.kernel.org
Cc:     Valentin Schneider <valentin.schneider@arm.com>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@kernel.org>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
        Sergei Trofimovich <slyfox@gentoo.org>,
        Anatoly Pugachev <matorola@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-kernel@vger.kernel.org
Subject: [PATCH v2 4.19 2/3] sched/topology: Fix sched_domain_topology_level alloc in sched_init_numa()
Date:   Wed, 16 Mar 2022 10:48:07 -0600
Message-Id: <20220316164808.569272-3-dann.frazier@canonical.com>
In-Reply-To: <20220316164808.569272-1-dann.frazier@canonical.com>
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From: Dietmar Eggemann <dietmar.eggemann@arm.com>

commit 71e5f6644fb2f3304fcb310145ded234a37e7cc1 upstream.

Commit "sched/topology: Make sched_init_numa() use a set for the
deduplicating sort" allocates 'i + nr_levels (level)' instead of
'i + nr_levels + 1' sched_domain_topology_level.

This led to an Oops (on Arm64 juno with CONFIG_SCHED_DEBUG):

sched_init_domains
  build_sched_domains()
    __free_domain_allocs()
      __sdt_free() {
	...
        for_each_sd_topology(tl)
	  ...
          sd = *per_cpu_ptr(sdd->sd, j); <--
	  ...
      }

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Tested-by: Barry Song <song.bao.hua@hisilicon.com>
Link: https://lkml.kernel.org/r/6000e39e-7d28-c360-9cd6-8798fd22a9bf@arm.com
Signed-off-by: dann frazier <dann.frazier@canonical.com>
---
 kernel/sched/topology.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 0826f3f4920a..02e85cd233d4 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -1428,7 +1428,7 @@ void sched_init_numa(void)
 	/* Compute default topology size */
 	for (i = 0; sched_domain_topology[i].mask; i++);
 
-	tl = kzalloc((i + nr_levels) *
+	tl = kzalloc((i + nr_levels + 1) *
 			sizeof(struct sched_domain_topology_level), GFP_KERNEL);
 	if (!tl)
 		return;
-- 
2.35.1