linux-kernel - [PATCH] workqueue: Remove duplicate worqueue attributes allocation

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Message-Id: <20230906173904.475722-1-catalin.marinas@arm.com>
Date:   Wed,  6 Sep 2023 18:39:04 +0100
From:   Catalin Marinas <catalin.marinas@....com>
To:     tj@...nel.org
Cc:     linux-kernel@...r.kernel.org, dhavale@...gle.com
Subject: [PATCH] workqueue: Remove duplicate worqueue attributes allocation

Commit 84193c07105c ("workqueue: Generalize unbound CPU pods")
inadvertently introduced another call to alloc_workqueue_attrs()
overriding the pointer returned by a previous alloc_workqueue_attrs() a
few lines up in workqueue_init_early(). This leads to a kmemleak report:

unreferenced object 0xffff000040015000 (size 96):
  comm "swapper/0", pid 0, jiffies 4294892296 (age 163.956s)
  hex dump (first 32 bytes):
    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 00 00 00 00 00 00 00  ................
  backtrace:
    [<000000004cec0d50>] __kmem_cache_alloc_node+0x1c4/0x288
    [<0000000083361c2a>] kmalloc_trace+0x20/0x2c
    [<000000005ca61f11>] workqueue_init_early+0xe4/0x538
    [<000000004e6ea358>] start_kernel+0x23c/0x5ec
    [<00000000aea9761e>] __primary_switched+0xbc/0xc4

Remove the first allocation.

Fixes: 84193c07105c ("workqueue: Generalize unbound CPU pods")
Signed-off-by: Catalin Marinas <catalin.marinas@....com>
Cc: Tejun Heo <tj@...nel.org>
---

I've seen this mentioned by Sandeep as well but I couldn't find a patch,
so here it is.

https://lore.kernel.org/r/CAB=BE-S=cxewXu7nqJY1DC5w9Bapar_C0cTjpZOQ-Qd5GGwYyw@mail.gmail.com/

 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);