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From:   John Ogness <john.ogness@linutronix.de>
To:     Tejun Heo <tj@kernel.org>
Cc:     Lai Jiangshan <jiangshanlai@gmail.com>,
        linux-kernel@vger.kernel.org
Subject: [PATCH] workqueue: fix duplicate wq_update_pod_attrs_buf allocation
Date:   Wed, 13 Sep 2023 12:22:34 +0206
Message-Id: <20230913101634.553699-1-john.ogness@linutronix.de>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

One of the hunks for the patch resulting in
commit 84193c07105c ("workqueue: Generalize unbound CPU pods") was
applied incorrectly. This resulted in @wq_update_pod_attrs_buf
being allocated twice.

From the kmemleak detector:

unreferenced object 0xc0000000040074c0 (size 64):
  comm "swapper/0", pid 0, jiffies 4294937296 (age 1936.580s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 03  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<0000000076b83a6e>] .kmalloc_trace+0x54/0x190
    [<00000000898f2356>] .alloc_workqueue_attrs+0x2c/0x60
    [<0000000063365e1f>] .workqueue_init_early+0xe4/0x4b8
    [<00000000ca97ff39>] .start_kernel+0x8d0/0xba4
    [<000000002ee12080>] start_here_common+0x1c/0x20

Remove the redundant allocation.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
---
 kernel/workqueue.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index c85825e17df8..43ab8399b72b 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -6524,9 +6524,6 @@ void __init workqueue_init_early(void)
 
 	pwq_cache = KMEM_CACHE(pool_workqueue, SLAB_PANIC);
 
-	wq_update_pod_attrs_buf = alloc_workqueue_attrs();
-	BUG_ON(!wq_update_pod_attrs_buf);
-
 	/* initialize WQ_AFFN_SYSTEM pods */
 	pt->pod_cpus = kcalloc(1, sizeof(pt->pod_cpus[0]), GFP_KERNEL);
 	pt->pod_node = kcalloc(1, sizeof(pt->pod_node[0]), GFP_KERNEL);

base-commit: 3669558bdf354cd352be955ef2764cde6a9bf5ec
-- 
2.39.2