linux-kernel - [PATCH] powerpc/pseries/cpuhp: Use alloc_cpumask_var() in pseries_cpu_hotplug

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Message-Id: <20211108164751.65565-1-longman@redhat.com>
Date:   Mon,  8 Nov 2021 11:47:51 -0500
From:   Waiman Long <longman@...hat.com>
To:     Michael Ellerman <mpe@...erman.id.au>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Daniel Henrique Barboza <danielhb413@...il.com>,
        Nathan Lynch <nathanl@...ux.ibm.com>,
        "Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        Laurent Dufour <ldufour@...ux.ibm.com>,
        Nicholas Piggin <npiggin@...il.com>,
        Zhang Xiaoxu <zhangxiaoxu5@...wei.com>,
        Waiman Long <longman@...hat.com>
Subject: [PATCH] powerpc/pseries/cpuhp: Use alloc_cpumask_var() in pseries_cpu_hotplug_init()

It was found that the following warning message could be printed out when
booting the kernel on PowerPC systems that support LPAR:

[    0.129584] WARNING: CPU: 0 PID: 1 at mm/memblock.c:1451 memblock_alloc_internal+0x5c/0x104
[    0.129593] Modules linked in:
[    0.129598] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.14.0-11.el9.ppc64le+debug #1
[    0.129605] NIP:  c000000002040134 LR: c00000000204011c CTR: c0000000020241a8
[    0.129610] REGS: c000000005637760 TRAP: 0700   Not tainted  (5.14.0-11.el9.ppc64le+debug)
[    0.129616] MSR:  8000000002029033 <SF,VEC,EE,ME,IR,DR,RI,LE>  CR: 48000222  XER: 00000002
[    0.129635] CFAR: c0000000004d1cf4 IRQMASK: 0
[    0.129635] GPR00: c00000000204011c c000000005637a00 c000000002c94d00 0000000000000001
[    0.129635] GPR04: 0000000000000080 0000000000000000 0000000000000000 ffffffffffffffff
[    0.129635] GPR08: 0000000000000000 0000000000000003 c00000000205ac64 0000000000080000
[    0.129635] GPR12: 0000000000000000 c0000000049d0000 c000000000013078 0000000000000000
[    0.129635] GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[    0.129635] GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[    0.129635] GPR24: c000000002003808 c00000000146f7b8 0000000000000000 0000000000000100
[    0.129635] GPR28: c000000002d7cf80 0000000000000000 0000000000000008 0000000000000000
[    0.129710] NIP [c000000002040134] memblock_alloc_internal+0x5c/0x104
[    0.129717] LR [c00000000204011c] memblock_alloc_internal+0x44/0x104
[    0.129723] Call Trace:
[    0.129726] [c000000005637a00] [c000000005637a40] 0xc000000005637a40 (unreliable)
[    0.129735] [c000000005637a60] [c0000000020404d8] memblock_alloc_try_nid+0x94/0xcc
[    0.129743] [c000000005637af0] [c00000000205ac64] alloc_bootmem_cpumask_var+0x4c/0x9c
[    0.129751] [c000000005637b60] [c0000000020242e0] __machine_initcall_pseries_pseries_cpu_hotplug_init+0x138/0x1d8
[    0.129760] [c000000005637bf0] [c000000000012404] do_one_initcall+0xa4/0x4f0
[    0.129768] [c000000005637cd0] [c000000002005358] do_initcalls+0x140/0x18c
[    0.129776] [c000000005637d80] [c0000000020055b8] kernel_init_freeable+0x178/0x1d0
[    0.129783] [c000000005637db0] [c0000000000130a0] kernel_init+0x30/0x190
[    0.129790] [c000000005637e10] [c00000000000cef4] ret_from_kernel_thread+0x5c/0x64

The warning is printed in memblock_alloc_internal() because the slab
has been initialized when the initcalls are being processed. To
avoid the warning, change alloc_bootmem_cpumask_var() call in
pseries_cpu_hotplug_init() to alloc_cpumask_var() instead. Also
change cpumask_or() to cpumask_copy() or we will have to use
zalloc_cpumask_var().

Fixes: bd1dd4c5f528 ("powerpc/pseries: Prevent free CPU ids being reused on another node")
Signed-off-by: Waiman Long <longman@...hat.com>
---
 arch/powerpc/platforms/pseries/hotplug-cpu.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index 5ab44600c8d3..e8e08d916b16 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -864,12 +864,12 @@ static int __init pseries_cpu_hotplug_init(void)
 	/* Processors can be added/removed only on LPAR */
 	if (firmware_has_feature(FW_FEATURE_LPAR)) {
 		for_each_node(node) {
-			alloc_bootmem_cpumask_var(&node_recorded_ids_map[node]);
+			alloc_cpumask_var(&node_recorded_ids_map[node],
+					  GFP_KERNEL|GFP_NOWAIT);
 
 			/* Record ids of CPU added at boot time */
-			cpumask_or(node_recorded_ids_map[node],
-				   node_recorded_ids_map[node],
-				   cpumask_of_node(node));
+			cpumask_copy(node_recorded_ids_map[node],
+				     cpumask_of_node(node));
 		}
 
 		of_reconfig_notifier_register(&pseries_smp_nb);
-- 
2.27.0