[PATCH v2 0/9] check the node id consistently across different arches

[PATCH v2 0/9] check the node id consistently across different arches

[Yunsheng Lin]

According to Section 6.2.14 from ACPI spec 6.3 [1], the
setting of proximity domain is optional, as below:

This optional object is used to describe proximity domain
associations within a machine. _PXM evaluates to an integer
that identifies a device as belonging to a Proximity Domain
defined in the System Resource Affinity Table (SRAT).

When enabling KASAN and bios has not implemented the proximity
domain of the hns3 device, there is a global-out-of-bounds error
below:

[   42.970381] ==================================================================
[   42.977595] BUG: KASAN: global-out-of-bounds in __bitmap_weight+0x48/0xb0
[   42.984370] Read of size 8 at addr ffff20008cdf8790 by task kworker/0:1/13
[   42.991230]
[   42.992712] CPU: 0 PID: 13 Comm: kworker/0:1 Tainted: G           O      5.2.0-rc4-g8bde06a-dirty #3
[   43.001830] Hardware name: Huawei TaiShan 2280 V2/BC82AMDA, BIOS TA BIOS 2280-A CS V2.B050.01 08/08/2019
[   43.011298] Workqueue: events work_for_cpu_fn
[   43.015643] Call trace:
[   43.018078]  dump_backtrace+0x0/0x1e8
[   43.021727]  show_stack+0x14/0x20
[   43.025031]  dump_stack+0xc4/0xfc
[   43.028335]  print_address_description+0x178/0x270
[   43.033113]  __kasan_report+0x164/0x1b8
[   43.036936]  kasan_report+0xc/0x18
[   43.040325]  __asan_load8+0x84/0xa8
[   43.043801]  __bitmap_weight+0x48/0xb0
[   43.047552]  hclge_init_ae_dev+0x988/0x1e78 [hclge]
[   43.052418]  hnae3_register_ae_dev+0xcc/0x278 [hnae3]
[   43.057467]  hns3_probe+0xe0/0x120 [hns3]
[   43.061464]  local_pci_probe+0x74/0xf0
[   43.065200]  work_for_cpu_fn+0x2c/0x48
[   43.068937]  process_one_work+0x3c0/0x878
[   43.072934]  worker_thread+0x400/0x670
[   43.076670]  kthread+0x1b0/0x1b8
[   43.079885]  ret_from_fork+0x10/0x18
[   43.083446]
[   43.084925] The buggy address belongs to the variable:
[   43.090052]  numa_distance+0x30/0x40
[   43.093613]
[   43.095091] Memory state around the buggy address:
[   43.099870]  ffff20008cdf8680: fa fa fa fa 04 fa fa fa fa fa fa fa 00 00 fa fa
[   43.107078]  ffff20008cdf8700: fa fa fa fa 04 fa fa fa fa fa fa fa 00 fa fa fa
[   43.114286] >ffff20008cdf8780: fa fa fa fa 00 00 00 00 00 00 00 00 fa fa fa fa
[   43.121494]                          ^
[   43.125230]  ffff20008cdf8800: 01 fa fa fa fa fa fa fa 04 fa fa fa fa fa fa fa
[   43.132439]  ffff20008cdf8880: fa fa fa fa fa fa fa fa 00 00 fa fa fa fa fa fa
[   43.139646] ==================================================================

As suggested [2] by Michal Hocko:
"if the specification really allows to provide NUMA_NO_NODE (-1) then
the code really has to be prepared for that. And ideally all arches
should deal with that."

This patchset checks the node id with the below case consistently
across different arches in order to be compliant with spec and
backward compatible as much as possible:
1. if node_id < 0, return cpu_online_mask
2. if node_id >= nr_node_ids, return cpu_none_mask
3. if node_to_cpumask_map[node_id] is NULL, return cpu_online_mask

Note:
1. Only arm64 has been compile tested and tested on real board.
2. x86 has been compile tested with defconfig.
3. Other arch has not been compile tested or tested on real board.

Changelog:
V2: Change commit log as suggested by Michal Hocko, and make the change to
    other arches as well.

[1] https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf
[2] https://patchwork.kernel.org/patch/11122823/

Yunsheng Lin (9):
  arm64: numa: check the node id consistently for arm64
  x86: numa: check the node id consistently for x86
  alpha: numa: check the node id consistently for alpha
  powerpc: numa: check the node id consistently for powerpc
  s390: numa: check the node id consistently for s390
  sh: numa: check the node id consistently for sh
  sparc64: numa: check the node id consistently for sparc64
  mips: numa: check the node id consistently for mips ip27
  mips: numa: check the node id consistently for mips loongson64

 arch/alpha/include/asm/topology.h                |  7 +++++--
 arch/arm64/include/asm/numa.h                    |  6 ++++++
 arch/arm64/mm/numa.c                             |  2 +-
 arch/mips/include/asm/mach-ip27/topology.h       | 15 ++++++++++++---
 arch/mips/include/asm/mach-loongson64/topology.h | 12 +++++++++++-
 arch/powerpc/include/asm/topology.h              | 13 ++++++++++---
 arch/s390/include/asm/topology.h                 |  6 ++++++
 arch/sh/include/asm/topology.h                   | 14 +++++++++++++-
 arch/sparc/include/asm/topology_64.h             | 16 +++++++++++++---
 arch/x86/include/asm/topology.h                  |  6 ++++++
 arch/x86/mm/numa.c                               |  2 +-
 11 files changed, 84 insertions(+), 15 deletions(-)

-- 
2.8.1


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[PATCH v2 1/9] arm64: numa: check the node id consistently for arm64

[Yunsheng Lin]

According to Section 6.2.14 from ACPI spec 6.3 [1], the setting
of proximity domain is optional, as below:

This optional object is used to describe proximity domain
associations within a machine. _PXM evaluates to an integer
that identifies a device as belonging to a Proximity Domain
defined in the System Resource Affinity Table (SRAT).

When enabling KASAN and bios has not implemented the proximity
domain of the hns3 device, there is a global-out-of-bounds error
below:

[   42.970381] ==================================================================
[   42.977595] BUG: KASAN: global-out-of-bounds in __bitmap_weight+0x48/0xb0
[   42.984370] Read of size 8 at addr ffff20008cdf8790 by task kworker/0:1/13
[   42.991230]
[   42.992712] CPU: 0 PID: 13 Comm: kworker/0:1 Tainted: G           O      5.2.0-rc4-g8bde06a-dirty #3
[   43.001830] Hardware name: Huawei TaiShan 2280 V2/BC82AMDA, BIOS TA BIOS 2280-A CS V2.B050.01 08/08/2019
[   43.011298] Workqueue: events work_for_cpu_fn
[   43.015643] Call trace:
[   43.018078]  dump_backtrace+0x0/0x1e8
[   43.021727]  show_stack+0x14/0x20
[   43.025031]  dump_stack+0xc4/0xfc
[   43.028335]  print_address_description+0x178/0x270
[   43.033113]  __kasan_report+0x164/0x1b8
[   43.036936]  kasan_report+0xc/0x18
[   43.040325]  __asan_load8+0x84/0xa8
[   43.043801]  __bitmap_weight+0x48/0xb0
[   43.047552]  hclge_init_ae_dev+0x988/0x1e78 [hclge]
[   43.052418]  hnae3_register_ae_dev+0xcc/0x278 [hnae3]
[   43.057467]  hns3_probe+0xe0/0x120 [hns3]
[   43.061464]  local_pci_probe+0x74/0xf0
[   43.065200]  work_for_cpu_fn+0x2c/0x48
[   43.068937]  process_one_work+0x3c0/0x878
[   43.072934]  worker_thread+0x400/0x670
[   43.076670]  kthread+0x1b0/0x1b8
[   43.079885]  ret_from_fork+0x10/0x18
[   43.083446]
[   43.084925] The buggy address belongs to the variable:
[   43.090052]  numa_distance+0x30/0x40
[   43.093613]
[   43.095091] Memory state around the buggy address:
[   43.099870]  ffff20008cdf8680: fa fa fa fa 04 fa fa fa fa fa fa fa 00 00 fa fa
[   43.107078]  ffff20008cdf8700: fa fa fa fa 04 fa fa fa fa fa fa fa 00 fa fa fa
[   43.114286] >ffff20008cdf8780: fa fa fa fa 00 00 00 00 00 00 00 00 fa fa fa fa
[   43.121494]                          ^
[   43.125230]  ffff20008cdf8800: 01 fa fa fa fa fa fa fa 04 fa fa fa fa fa fa fa
[   43.132439]  ffff20008cdf8880: fa fa fa fa fa fa fa fa 00 00 fa fa fa fa fa fa
[   43.139646] ==================================================================

This patch checks node id with the below case before returning
node_to_cpumask_map[node]:
1. if node_id >= nr_node_ids, return cpu_none_mask
2. if node_id < 0, return cpu_online_mask
3. if node_to_cpumask_map[node_id] is NULL, return cpu_online_mask

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
---
 arch/arm64/include/asm/numa.h | 6 ++++++
 arch/arm64/mm/numa.c          | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/numa.h b/arch/arm64/include/asm/numa.h
index 626ad01..65a0ef6 100644
--- a/arch/arm64/include/asm/numa.h
+++ b/arch/arm64/include/asm/numa.h
@@ -25,6 +25,12 @@ const struct cpumask *cpumask_of_node(int node);
 /* Returns a pointer to the cpumask of CPUs on Node 'node'. */
 static inline const struct cpumask *cpumask_of_node(int node)
 {
+	if (node >= nr_node_ids)
+		return cpu_none_mask;
+
+	if (node < 0 || !node_to_cpumask_map[node])
+		return cpu_online_mask;
+
 	return node_to_cpumask_map[node];
 }
 #endif
diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c
index 4f241cc..7eca267 100644
--- a/arch/arm64/mm/numa.c
+++ b/arch/arm64/mm/numa.c
@@ -49,7 +49,7 @@ const struct cpumask *cpumask_of_node(int node)
 	if (WARN_ON(node >= nr_node_ids))
 		return cpu_none_mask;
 
-	if (WARN_ON(node_to_cpumask_map[node] == NULL))
+	if (WARN_ON(node < 0 || !node_to_cpumask_map[node]))
 		return cpu_online_mask;
 
 	return node_to_cpumask_map[node];
-- 
2.8.1


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[PATCH v2 2/9] x86: numa: check the node id consistently for x86

[Yunsheng Lin]

According to Section 6.2.14 from ACPI spec 6.3 [1], the setting
of proximity domain is optional, as below:

This optional object is used to describe proximity domain
associations within a machine. _PXM evaluates to an integer
that identifies a device as belonging to a Proximity Domain
defined in the System Resource Affinity Table (SRAT).

This patch checks node id with the below case before returning
node_to_cpumask_map[node]:
1. if node_id >= nr_node_ids, return cpu_none_mask
2. if node_id < 0, return cpu_online_mask
3. if node_to_cpumask_map[node_id] is NULL, return cpu_online_mask

[1] https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
---
 arch/x86/include/asm/topology.h | 6 ++++++
 arch/x86/mm/numa.c              | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index 4b14d23..f36e9c8 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -69,6 +69,12 @@ extern const struct cpumask *cpumask_of_node(int node);
 /* Returns a pointer to the cpumask of CPUs on Node 'node'. */
 static inline const struct cpumask *cpumask_of_node(int node)
 {
+	if (node >= nr_node_ids)
+		return cpu_none_mask;
+
+	if (node < 0 || !node_to_cpumask_map[node])
+		return cpu_online_mask;
+
 	return node_to_cpumask_map[node];
 }
 #endif
diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index e6dad60..5e393d2 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -868,7 +868,7 @@ const struct cpumask *cpumask_of_node(int node)
 		dump_stack();
 		return cpu_none_mask;
 	}
-	if (node_to_cpumask_map[node] == NULL) {
+	if (node < 0 || !node_to_cpumask_map[node]) {
 		printk(KERN_WARNING
 			"cpumask_of_node(%d): no node_to_cpumask_map!\n",
 			node);
-- 
2.8.1


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[PATCH v2 3/9] alpha: numa: check the node id consistently for alpha

[Yunsheng Lin]

According to Section 6.2.14 from ACPI spec 6.3 [1], the setting
of proximity domain is optional, as below:

This optional object is used to describe proximity domain
associations within a machine. _PXM evaluates to an integer
that identifies a device as belonging to a Proximity Domain
defined in the System Resource Affinity Table (SRAT).

This patch checks node id with the below case before returning
node_to_cpumask_map[node]:
1. if node_id >= nr_node_ids, return cpu_none_mask
2. if node_id < 0, return cpu_online_mask
3. if node_to_cpumask_map[node_id] is NULL, return cpu_online_mask

[1] https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
---
note node_to_cpumask_map[node] is already a pointer, so the
cpumask_clear should be called with node_to_cpumask_map[node]
instead of &node_to_cpumask_map[node]? And cpumask_of_node()
function need to be inlined when defined in a header file?
If the above are problems, maybe another patch to fix or clean
it up.
---
 arch/alpha/include/asm/topology.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/alpha/include/asm/topology.h b/arch/alpha/include/asm/topology.h
index 5a77a40..9e0b1cd1 100644
--- a/arch/alpha/include/asm/topology.h
+++ b/arch/alpha/include/asm/topology.h
@@ -30,8 +30,11 @@ static const struct cpumask *cpumask_of_node(int node)
 {
 	int cpu;
 
-	if (node == NUMA_NO_NODE)
-		return cpu_all_mask;
+	if (node >= nr_node_ids)
+		return cpu_none_mask;
+
+	if (node < 0 || !node_to_cpumask_map[node])
+		return cpu_online_mask;
 
 	cpumask_clear(&node_to_cpumask_map[node]);
 
-- 
2.8.1


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[PATCH v2 4/9] powerpc: numa: check the node id consistently for powerpc

[Yunsheng Lin]

According to Section 6.2.14 from ACPI spec 6.3 [1], the setting
of proximity domain is optional, as below:

This optional object is used to describe proximity domain
associations within a machine. _PXM evaluates to an integer
that identifies a device as belonging to a Proximity Domain
defined in the System Resource Affinity Table (SRAT).

This patch checks node id with the below case before returning
node_to_cpumask_map[node]:
1. if node_id >= nr_node_ids, return cpu_none_mask
2. if node_id < 0, return cpu_online_mask
3. if node_to_cpumask_map[node_id] is NULL, return cpu_online_mask

[1] https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
---
 arch/powerpc/include/asm/topology.h | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
index 2f7e1ea..217dc9b 100644
--- a/arch/powerpc/include/asm/topology.h
+++ b/arch/powerpc/include/asm/topology.h
@@ -17,9 +17,16 @@ struct device_node;
 
 #include <asm/mmzone.h>
 
-#define cpumask_of_node(node) ((node) == -1 ?				\
-			       cpu_all_mask :				\
-			       node_to_cpumask_map[node])
+static inline const struct cpumask *cpumask_of_node(int node)
+{
+	if (node >= nr_node_ids)
+		return cpu_none_mask;
+
+	if (node < 0 || !node_to_cpumask_map[node])
+		return cpu_online_mask;
+
+	return node_to_cpumask_map[node];
+}
 
 struct pci_bus;
 #ifdef CONFIG_PCI
-- 
2.8.1


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[PATCH v2 5/9] s390: numa: check the node id consistently for s390

[Yunsheng Lin]

According to Section 6.2.14 from ACPI spec 6.3 [1], the setting
of proximity domain is optional, as below:

This optional object is used to describe proximity domain
associations within a machine. _PXM evaluates to an integer
that identifies a device as belonging to a Proximity Domain
defined in the System Resource Affinity Table (SRAT).

This patch checks node id with the below case before returning
node_to_cpumask_map[node]:
1. if node_id >= nr_node_ids, return cpu_none_mask
2. if node_id < 0, return cpu_online_mask
3. if node_to_cpumask_map[node_id] is NULL, return cpu_online_mask

[1] https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
---
Note node_to_cpumask_map[node] is already a pointer, so
returning &node_to_cpumask_map[node] does not seem to
be correct, if this is problem, maybe clean it up in another
patch.
---
 arch/s390/include/asm/topology.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/s390/include/asm/topology.h b/arch/s390/include/asm/topology.h
index cca406f..75340ca 100644
--- a/arch/s390/include/asm/topology.h
+++ b/arch/s390/include/asm/topology.h
@@ -78,6 +78,12 @@ static inline int cpu_to_node(int cpu)
 #define cpumask_of_node cpumask_of_node
 static inline const struct cpumask *cpumask_of_node(int node)
 {
+	if (node >= nr_node_ids)
+		return cpu_none_mask;
+
+	if (node < 0 || !node_to_cpumask_map[node])
+		return cpu_online_mask;
+
 	return &node_to_cpumask_map[node];
 }
 
-- 
2.8.1


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[PATCH v2 6/9] sh: numa: check the node id consistently for sh

[Yunsheng Lin]

According to Section 6.2.14 from ACPI spec 6.3 [1], the setting
of proximity domain is optional, as below:

This optional object is used to describe proximity domain
associations within a machine. _PXM evaluates to an integer
that identifies a device as belonging to a Proximity Domain
defined in the System Resource Affinity Table (SRAT).

It seems sh does not have real numa support or uncompleted
numa support, this patch still checks node id with the below
case to ensure future support is consistent:
1. if node_id >= nr_node_ids, return cpu_none_mask
2. if node_id < 0, return cpu_online_mask
3. if node_to_cpumask_map[node_id] is NULL, return cpu_online_mask

[1] https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
---
 arch/sh/include/asm/topology.h | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/sh/include/asm/topology.h b/arch/sh/include/asm/topology.h
index 1db470e..e71e0a0 100644
--- a/arch/sh/include/asm/topology.h
+++ b/arch/sh/include/asm/topology.h
@@ -6,7 +6,19 @@
 
 #define cpu_to_node(cpu)	((void)(cpu),0)
 
-#define cpumask_of_node(node)	((void)node, cpu_online_mask)
+static inline const struct cpumask *cpumask_of_node(int node)
+{
+	if (node >= nr_node_ids)
+		return cpu_none_mask;
+
+	if (node < 0 || !node_to_cpumask_map[node])
+		return cpu_online_mask;
+
+	/* Should return actual mask based on node_to_cpumask_map
+	 * if sh arch supports real numa node.
+	 */
+	return cpu_online_mask;
+}
 
 #define pcibus_to_node(bus)	((void)(bus), -1)
 #define cpumask_of_pcibus(bus)	(pcibus_to_node(bus) == -1 ? \
-- 
2.8.1


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[PATCH v2 7/9] sparc64: numa: check the node id consistently for sparc64

[Yunsheng Lin]

According to Section 6.2.14 from ACPI spec 6.3 [1], the setting
of proximity domain is optional, as below:

This optional object is used to describe proximity domain
associations within a machine. _PXM evaluates to an integer
that identifies a device as belonging to a Proximity Domain
defined in the System Resource Affinity Table (SRAT).

This patch checks node id with the below case before returning
&numa_cpumask_lookup_table[node]:
1. if node_id >= nr_node_ids, return cpu_none_mask
2. if node_id < 0, return cpu_online_mask
3. Since numa_cpumask_lookup_table is not a pointer, a comment
   is added to indicate that

[1] https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
---
 arch/sparc/include/asm/topology_64.h | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/arch/sparc/include/asm/topology_64.h b/arch/sparc/include/asm/topology_64.h
index 34c628a..66a7917 100644
--- a/arch/sparc/include/asm/topology_64.h
+++ b/arch/sparc/include/asm/topology_64.h
@@ -11,9 +11,19 @@ static inline int cpu_to_node(int cpu)
 	return numa_cpu_lookup_table[cpu];
 }
 
-#define cpumask_of_node(node) ((node) == -1 ?				\
-			       cpu_all_mask :				\
-			       &numa_cpumask_lookup_table[node])
+static inline const struct cpumask *cpumask_of_node(int node)
+{
+	if (node >= MAX_NUMNODES)
+		return cpu_none_mask;
+
+	/* numa_cpumask_lookup_table[node] is not a pointer, so
+	 * no need to check for NULL here.
+	 */
+	if (node < 0)
+		return cpu_online_mask;
+
+	return &numa_cpumask_lookup_table[node];
+}
 
 struct pci_bus;
 #ifdef CONFIG_PCI
-- 
2.8.1


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[PATCH v2 8/9] mips: numa: check the node id consistently for mips ip27

[Yunsheng Lin]

According to Section 6.2.14 from ACPI spec 6.3 [1], the setting
of proximity domain is optional, as below:

This optional object is used to describe proximity domain
associations within a machine. _PXM evaluates to an integer
that identifies a device as belonging to a Proximity Domain
defined in the System Resource Affinity Table (SRAT).

Since mips ip27 uses hub_data instead of node_to_cpumask_map,
this patch checks node id with the below case before returning
&hub_data(node)->h_cpus:
1. if node_id >= MAX_COMPACT_NODES, return cpu_none_mask
2. if node_id < 0, return cpu_online_mask
3. if hub_data(node) is NULL, return cpu_online_mask

[1] https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
---
 arch/mips/include/asm/mach-ip27/topology.h | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/arch/mips/include/asm/mach-ip27/topology.h b/arch/mips/include/asm/mach-ip27/topology.h
index 965f079..914a55a 100644
--- a/arch/mips/include/asm/mach-ip27/topology.h
+++ b/arch/mips/include/asm/mach-ip27/topology.h
@@ -15,9 +15,18 @@ struct cpuinfo_ip27 {
 extern struct cpuinfo_ip27 sn_cpu_info[NR_CPUS];
 
 #define cpu_to_node(cpu)	(sn_cpu_info[(cpu)].p_nodeid)
-#define cpumask_of_node(node)	((node) == -1 ?				\
-				 cpu_all_mask :				\
-				 &hub_data(node)->h_cpus)
+
+static inline const struct cpumask *cpumask_of_node(int node)
+{
+	if (node >= MAX_COMPACT_NODES)
+		return cpu_none_mask;
+
+	if (node < 0 || !hub_data(node))
+		return cpu_online_mask;
+
+	return &hub_data(node)->h_cpus;
+}
+
 struct pci_bus;
 extern int pcibus_to_node(struct pci_bus *);
 
-- 
2.8.1


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[PATCH v2 9/9] mips: numa: check the node id consistently for mips loongson64

[Yunsheng Lin]

According to Section 6.2.14 from ACPI spec 6.3 [1], the setting
of proximity domain is optional, as below:

This optional object is used to describe proximity domain
associations within a machine. _PXM evaluates to an integer
that identifies a device as belonging to a Proximity Domain
defined in the System Resource Affinity Table (SRAT).

Since mips loongson64 uses __node_data instead of
node_to_cpumask_map, this patch checks node id with the below
case before returning &__node_data[node]->cpumask:
1. if node_id >= MAX_NUMNODES, return cpu_none_mask
2. if node_id < 0, return cpu_online_mask
3. if hub_data(node) is NULL, return cpu_online_mask

[1] https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
---
 arch/mips/include/asm/mach-loongson64/topology.h | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/mips/include/asm/mach-loongson64/topology.h b/arch/mips/include/asm/mach-loongson64/topology.h
index 7ff819a..b19b983 100644
--- a/arch/mips/include/asm/mach-loongson64/topology.h
+++ b/arch/mips/include/asm/mach-loongson64/topology.h
@@ -5,7 +5,17 @@
 #ifdef CONFIG_NUMA
 
 #define cpu_to_node(cpu)	(cpu_logical_map(cpu) >> 2)
-#define cpumask_of_node(node)	(&__node_data[(node)]->cpumask)
+
+static inline const struct cpumask *cpumask_of_node(int node)
+{
+	if (node >= MAX_NUMNODES)
+		return cpu_none_mask;
+
+	if (node < 0 || !__node_data[node])
+		return cpu_online_mask;
+
+	return &__node_data[node]->cpumask;
+}
 
 struct pci_bus;
 extern int pcibus_to_node(struct pci_bus *);
-- 
2.8.1


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Re: [PATCH v2 7/9] sparc64: numa: check the node id consistently for sparc64

[David Miller]

From: Yunsheng Lin <linyunsheng@huawei.com>
Date: Sat, 31 Aug 2019 13:58:21 +0800

> According to Section 6.2.14 from ACPI spec 6.3 [1], the setting
> of proximity domain is optional, as below:

What in the world does the ACPI spec have to do with sparc64 NUMA
node ID checking?

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Re: [PATCH v2 2/9] x86: numa: check the node id consistently for x86

[Peter Zijlstra]

On Sat, Aug 31, 2019 at 01:58:16PM +0800, Yunsheng Lin wrote:
> According to Section 6.2.14 from ACPI spec 6.3 [1], the setting
> of proximity domain is optional, as below:
> 
> This optional object is used to describe proximity domain
> associations within a machine. _PXM evaluates to an integer
> that identifies a device as belonging to a Proximity Domain
> defined in the System Resource Affinity Table (SRAT).

That's just words.. what does it actually mean?

> This patch checks node id with the below case before returning
> node_to_cpumask_map[node]:
> 1. if node_id >= nr_node_ids, return cpu_none_mask
> 2. if node_id < 0, return cpu_online_mask
> 3. if node_to_cpumask_map[node_id] is NULL, return cpu_online_mask
> 
> [1] https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf
> 
> Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
> ---
>  arch/x86/include/asm/topology.h | 6 ++++++
>  arch/x86/mm/numa.c              | 2 +-
>  2 files changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
> index 4b14d23..f36e9c8 100644
> --- a/arch/x86/include/asm/topology.h
> +++ b/arch/x86/include/asm/topology.h
> @@ -69,6 +69,12 @@ extern const struct cpumask *cpumask_of_node(int node);
>  /* Returns a pointer to the cpumask of CPUs on Node 'node'. */
>  static inline const struct cpumask *cpumask_of_node(int node)
>  {
> +	if (node >= nr_node_ids)
> +		return cpu_none_mask;
> +
> +	if (node < 0 || !node_to_cpumask_map[node])
> +		return cpu_online_mask;
> +
>  	return node_to_cpumask_map[node];
>  }
>  #endif

I _reallly_ hate this. Users are expected to use valid numa ids. Now
we're adding all this checking to all users. Why do we want to do that?

Using '(unsigned)node >= nr_nods_ids' is an error.

> diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
> index e6dad60..5e393d2 100644
> --- a/arch/x86/mm/numa.c
> +++ b/arch/x86/mm/numa.c
> @@ -868,7 +868,7 @@ const struct cpumask *cpumask_of_node(int node)
>  		dump_stack();
>  		return cpu_none_mask;
>  	}
> -	if (node_to_cpumask_map[node] == NULL) {
> +	if (node < 0 || !node_to_cpumask_map[node]) {
>  		printk(KERN_WARNING
>  			"cpumask_of_node(%d): no node_to_cpumask_map!\n",
>  			node);
> -- 
> 2.8.1
> 

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Re: [PATCH v2 7/9] sparc64: numa: check the node id consistently for sparc64

[Yunsheng Lin]

On 2019/8/31 14:53, David Miller wrote:
> From: Yunsheng Lin <linyunsheng@huawei.com>
> Date: Sat, 31 Aug 2019 13:58:21 +0800
> 
>> According to Section 6.2.14 from ACPI spec 6.3 [1], the setting
>> of proximity domain is optional, as below:
> 
> What in the world does the ACPI spec have to do with sparc64 NUMA
> node ID checking?

I am not sure I understand your question fully here.

Here is my issue when the bios does not implement the proximity domain
of a device because the feature is optional according to the ACPI spec,
the dev_to_node(dev) return -1, which causes out of bound access when
using the value to get the device's cpu mask by calling cpumask_of_node.

Did you mean sparc64 system does not has ACPI, the device's node id will
not specified by ACPI, so the ACPI is unrelated here?

Or did you mean the commit log is not clear enough to justify the change?

Or did you mean this problem should be fixed in somewhere else?

Any detail advice and suggestion will be very helpful, thanks.

> 
> .
> 


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Re: [PATCH v2 2/9] x86: numa: check the node id consistently for x86

[Yunsheng Lin]

On 2019/8/31 16:55, Peter Zijlstra wrote:
> On Sat, Aug 31, 2019 at 01:58:16PM +0800, Yunsheng Lin wrote:
>> According to Section 6.2.14 from ACPI spec 6.3 [1], the setting
>> of proximity domain is optional, as below:
>>
>> This optional object is used to describe proximity domain
>> associations within a machine. _PXM evaluates to an integer
>> that identifies a device as belonging to a Proximity Domain
>> defined in the System Resource Affinity Table (SRAT).
> 
> That's just words.. what does it actually mean?

It means the dev_to_node(dev) may return -1 if the bios does not
implement the proximity domain feature, user may use that value
to call cpumask_of_node and cpumask_of_node does not protect itself
from node id being -1, which causes out of bound access.

> 
>> This patch checks node id with the below case before returning
>> node_to_cpumask_map[node]:
>> 1. if node_id >= nr_node_ids, return cpu_none_mask
>> 2. if node_id < 0, return cpu_online_mask
>> 3. if node_to_cpumask_map[node_id] is NULL, return cpu_online_mask
>>
>> [1] https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf
>>
>> Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
>> ---
>>  arch/x86/include/asm/topology.h | 6 ++++++
>>  arch/x86/mm/numa.c              | 2 +-
>>  2 files changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
>> index 4b14d23..f36e9c8 100644
>> --- a/arch/x86/include/asm/topology.h
>> +++ b/arch/x86/include/asm/topology.h
>> @@ -69,6 +69,12 @@ extern const struct cpumask *cpumask_of_node(int node);
>>  /* Returns a pointer to the cpumask of CPUs on Node 'node'. */
>>  static inline const struct cpumask *cpumask_of_node(int node)
>>  {
>> +	if (node >= nr_node_ids)
>> +		return cpu_none_mask;
>> +
>> +	if (node < 0 || !node_to_cpumask_map[node])
>> +		return cpu_online_mask;
>> +
>>  	return node_to_cpumask_map[node];
>>  }
>>  #endif
> 
> I _reallly_ hate this. Users are expected to use valid numa ids. Now
> we're adding all this checking to all users. Why do we want to do that?

As above, the dev_to_node(dev) may return -1.

> 
> Using '(unsigned)node >= nr_nods_ids' is an error.

'node >= nr_node_ids' can be dropped if all user is expected to not call
cpumask_of_node with node id greater or equal to nr_nods_ids.

From what I can see, the problem can be fixed in three place:
1. Make user dev_to_node return a valid node id even when proximity
   domain is not set by bios(or node id set by buggy bios is not valid),
   which may need info from the numa system to make sure it will return
   a valid node.

2. User that call cpumask_of_node should ensure the node id is valid
   before calling cpumask_of_node, and user also need some info to
   make ensure node id is valid.

3. Make sure cpumask_of_node deal with invalid node id as this patchset.

Which one do you prefer to make sure node id is valid, or do you
have any better idea?

Any detail advice and suggestion will be very helpful, thanks.

> 
>> diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
>> index e6dad60..5e393d2 100644
>> --- a/arch/x86/mm/numa.c
>> +++ b/arch/x86/mm/numa.c
>> @@ -868,7 +868,7 @@ const struct cpumask *cpumask_of_node(int node)
>>  		dump_stack();
>>  		return cpu_none_mask;
>>  	}
>> -	if (node_to_cpumask_map[node] == NULL) {
>> +	if (node < 0 || !node_to_cpumask_map[node]) {
>>  		printk(KERN_WARNING
>>  			"cpumask_of_node(%d): no node_to_cpumask_map!\n",
>>  			node);
>> -- 
>> 2.8.1
>>
> 
> .
> 


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Re: [PATCH v2 8/9] mips: numa: check the node id consistently for mips ip27

[Paul Burton]

Hi Yunsheng,

On Sat, Aug 31, 2019 at 01:58:22PM +0800, Yunsheng Lin wrote:
> According to Section 6.2.14 from ACPI spec 6.3 [1], the setting
> of proximity domain is optional, as below:
> 
> This optional object is used to describe proximity domain
> associations within a machine. _PXM evaluates to an integer
> that identifies a device as belonging to a Proximity Domain
> defined in the System Resource Affinity Table (SRAT).
> 
> Since mips ip27 uses hub_data instead of node_to_cpumask_map,
> this patch checks node id with the below case before returning
> &hub_data(node)->h_cpus:
> 1. if node_id >= MAX_COMPACT_NODES, return cpu_none_mask
> 2. if node_id < 0, return cpu_online_mask
> 3. if hub_data(node) is NULL, return cpu_online_mask
> 
> [1] https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf

Similar to David's comment on the sparc patch, these systems don't use
ACPI so I don't see from your commit message why this change would be
relevant.

This same comment applies to patch 9 too.

Thanks,
    Paul

> 
> Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
> ---
>  arch/mips/include/asm/mach-ip27/topology.h | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/mips/include/asm/mach-ip27/topology.h b/arch/mips/include/asm/mach-ip27/topology.h
> index 965f079..914a55a 100644
> --- a/arch/mips/include/asm/mach-ip27/topology.h
> +++ b/arch/mips/include/asm/mach-ip27/topology.h
> @@ -15,9 +15,18 @@ struct cpuinfo_ip27 {
>  extern struct cpuinfo_ip27 sn_cpu_info[NR_CPUS];
>  
>  #define cpu_to_node(cpu)	(sn_cpu_info[(cpu)].p_nodeid)
> -#define cpumask_of_node(node)	((node) == -1 ?				\
> -				 cpu_all_mask :				\
> -				 &hub_data(node)->h_cpus)
> +
> +static inline const struct cpumask *cpumask_of_node(int node)
> +{
> +	if (node >= MAX_COMPACT_NODES)
> +		return cpu_none_mask;
> +
> +	if (node < 0 || !hub_data(node))
> +		return cpu_online_mask;
> +
> +	return &hub_data(node)->h_cpus;
> +}
> +
>  struct pci_bus;
>  extern int pcibus_to_node(struct pci_bus *);
>  
> -- 
> 2.8.1
> 

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Re: [PATCH v2 2/9] x86: numa: check the node id consistently for x86

[Peter Zijlstra]

On Sat, Aug 31, 2019 at 06:09:39PM +0800, Yunsheng Lin wrote:
> 
> 
> On 2019/8/31 16:55, Peter Zijlstra wrote:
> > On Sat, Aug 31, 2019 at 01:58:16PM +0800, Yunsheng Lin wrote:
> >> According to Section 6.2.14 from ACPI spec 6.3 [1], the setting
> >> of proximity domain is optional, as below:
> >>
> >> This optional object is used to describe proximity domain
> >> associations within a machine. _PXM evaluates to an integer
> >> that identifies a device as belonging to a Proximity Domain
> >> defined in the System Resource Affinity Table (SRAT).
> > 
> > That's just words.. what does it actually mean?
> 
> It means the dev_to_node(dev) may return -1 if the bios does not
> implement the proximity domain feature, user may use that value
> to call cpumask_of_node and cpumask_of_node does not protect itself
> from node id being -1, which causes out of bound access.

> >> @@ -69,6 +69,12 @@ extern const struct cpumask *cpumask_of_node(int node);
> >>  /* Returns a pointer to the cpumask of CPUs on Node 'node'. */
> >>  static inline const struct cpumask *cpumask_of_node(int node)
> >>  {
> >> +	if (node >= nr_node_ids)
> >> +		return cpu_none_mask;
> >> +
> >> +	if (node < 0 || !node_to_cpumask_map[node])
> >> +		return cpu_online_mask;
> >> +
> >>  	return node_to_cpumask_map[node];
> >>  }
> >>  #endif
> > 
> > I _reallly_ hate this. Users are expected to use valid numa ids. Now
> > we're adding all this checking to all users. Why do we want to do that?
> 
> As above, the dev_to_node(dev) may return -1.
> 
> > 
> > Using '(unsigned)node >= nr_nods_ids' is an error.
> 
> 'node >= nr_node_ids' can be dropped if all user is expected to not call
> cpumask_of_node with node id greater or equal to nr_nods_ids.

you copied my typo :-)

> From what I can see, the problem can be fixed in three place:
> 1. Make user dev_to_node return a valid node id even when proximity
>    domain is not set by bios(or node id set by buggy bios is not valid),
>    which may need info from the numa system to make sure it will return
>    a valid node.
> 
> 2. User that call cpumask_of_node should ensure the node id is valid
>    before calling cpumask_of_node, and user also need some info to
>    make ensure node id is valid.
> 
> 3. Make sure cpumask_of_node deal with invalid node id as this patchset.
> 
> Which one do you prefer to make sure node id is valid, or do you
> have any better idea?
> 
> Any detail advice and suggestion will be very helpful, thanks.

1) because even it is not set, the device really does belong to a node.
It is impossible a device will have magic uniform access to memory when
CPUs cannot.

2) is already true today, cpumask_of_node() requires a valid node_id.

3) is just wrong and increases overhead for everyone.

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Re: [PATCH v2 7/9] sparc64: numa: check the node id consistently for sparc64

[David Miller]

From: Yunsheng Lin <linyunsheng@huawei.com>
Date: Sat, 31 Aug 2019 16:57:04 +0800

> Did you mean sparc64 system does not has ACPI, the device's node id will
> not specified by ACPI, so the ACPI is unrelated here?

Yes, sparc64 never has and never will have ACPI.

This is also true for several other platforms where you have made this
change.

The assumption of your entire patch set is that the semantics of the
NUMA node ID are somehow completely defined by ACPI semantics.  Which
is not true.

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Re: [PATCH v2 2/9] x86: numa: check the node id consistently for x86

[Yunsheng Lin]

On 2019/9/1 0:12, Peter Zijlstra wrote:
> On Sat, Aug 31, 2019 at 06:09:39PM +0800, Yunsheng Lin wrote:
>>
>>
>> On 2019/8/31 16:55, Peter Zijlstra wrote:
>>> On Sat, Aug 31, 2019 at 01:58:16PM +0800, Yunsheng Lin wrote:
>>>> According to Section 6.2.14 from ACPI spec 6.3 [1], the setting
>>>> of proximity domain is optional, as below:
>>>>
>>>> This optional object is used to describe proximity domain
>>>> associations within a machine. _PXM evaluates to an integer
>>>> that identifies a device as belonging to a Proximity Domain
>>>> defined in the System Resource Affinity Table (SRAT).
>>>
>>> That's just words.. what does it actually mean?
>>
>> It means the dev_to_node(dev) may return -1 if the bios does not
>> implement the proximity domain feature, user may use that value
>> to call cpumask_of_node and cpumask_of_node does not protect itself
>> from node id being -1, which causes out of bound access.
> 
>>>> @@ -69,6 +69,12 @@ extern const struct cpumask *cpumask_of_node(int node);
>>>>  /* Returns a pointer to the cpumask of CPUs on Node 'node'. */
>>>>  static inline const struct cpumask *cpumask_of_node(int node)
>>>>  {
>>>> +	if (node >= nr_node_ids)
>>>> +		return cpu_none_mask;
>>>> +
>>>> +	if (node < 0 || !node_to_cpumask_map[node])
>>>> +		return cpu_online_mask;
>>>> +
>>>>  	return node_to_cpumask_map[node];
>>>>  }
>>>>  #endif
>>>
>>> I _reallly_ hate this. Users are expected to use valid numa ids. Now
>>> we're adding all this checking to all users. Why do we want to do that?
>>
>> As above, the dev_to_node(dev) may return -1.
>>
>>>
>>> Using '(unsigned)node >= nr_nods_ids' is an error.
>>
>> 'node >= nr_node_ids' can be dropped if all user is expected to not call
>> cpumask_of_node with node id greater or equal to nr_nods_ids.
> 
> you copied my typo :-)

I did note the typo, corrected the first one, but missed the second one :)

> 
>> From what I can see, the problem can be fixed in three place:
>> 1. Make user dev_to_node return a valid node id even when proximity
>>    domain is not set by bios(or node id set by buggy bios is not valid),
>>    which may need info from the numa system to make sure it will return
>>    a valid node.
>>
>> 2. User that call cpumask_of_node should ensure the node id is valid
>>    before calling cpumask_of_node, and user also need some info to
>>    make ensure node id is valid.
>>
>> 3. Make sure cpumask_of_node deal with invalid node id as this patchset.
>>
>> Which one do you prefer to make sure node id is valid, or do you
>> have any better idea?
>>
>> Any detail advice and suggestion will be very helpful, thanks.
> 
> 1) because even it is not set, the device really does belong to a node.
> It is impossible a device will have magic uniform access to memory when
> CPUs cannot.

So it means dev_to_node() will return either NUMA_NO_NODE or a
valid node id?

> 
> 2) is already true today, cpumask_of_node() requires a valid node_id.

Ok, most of the user does check node_id before calling
cpumask_of_node(), but does a little different type of checking:

1) some does " < 0" check;
2) some does "== NUMA_NO_NODE" check;
3) some does ">= MAX_NUMNODES" check;
4) some does "< 0 || >= MAX_NUMNODES || !node_online(node)" check.


> 
> 3) is just wrong and increases overhead for everyone.

Ok, cpumask_of_node() is also used in some critical path such
as scheduling, which may not need those checking, the overhead
is unnecessary.

But for non-critical path such as setup or configuration path,
it better to have consistent checking, and also simplify the
user code that calls cpumask_of_node().

Do you think it is worth the trouble to add a new function
such as cpumask_of_node_check(maybe some other name) to do
consistent checking?

Or caller just simply check if dev_to_node()'s return value is
NUMA_NO_NODE before calling cpumask_of_node()?


> 
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Re: [PATCH v2 7/9] sparc64: numa: check the node id consistently for sparc64

[Yunsheng Lin]

On 2019/9/1 4:02, David Miller wrote:
> From: Yunsheng Lin <linyunsheng@huawei.com>
> Date: Sat, 31 Aug 2019 16:57:04 +0800
> 
>> Did you mean sparc64 system does not has ACPI, the device's node id will
>> not specified by ACPI, so the ACPI is unrelated here?
> 
> Yes, sparc64 never has and never will have ACPI.
> 
> This is also true for several other platforms where you have made this
> change.
> 
> The assumption of your entire patch set is that the semantics of the
> NUMA node ID are somehow completely defined by ACPI semantics.  Which
> is not true.

Thanks for pointing out.

The NUMA node id in sparc64 system is defined by DT semantics?

> 
> .
> 


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Re: [PATCH v2 8/9] mips: numa: check the node id consistently for mips ip27

[Yunsheng Lin]

On 2019/8/31 23:45, Paul Burton wrote:
> Hi Yunsheng,
> 
> On Sat, Aug 31, 2019 at 01:58:22PM +0800, Yunsheng Lin wrote:
>> According to Section 6.2.14 from ACPI spec 6.3 [1], the setting
>> of proximity domain is optional, as below:
>>
>> This optional object is used to describe proximity domain
>> associations within a machine. _PXM evaluates to an integer
>> that identifies a device as belonging to a Proximity Domain
>> defined in the System Resource Affinity Table (SRAT).
>>
>> Since mips ip27 uses hub_data instead of node_to_cpumask_map,
>> this patch checks node id with the below case before returning
>> &hub_data(node)->h_cpus:
>> 1. if node_id >= MAX_COMPACT_NODES, return cpu_none_mask
>> 2. if node_id < 0, return cpu_online_mask
>> 3. if hub_data(node) is NULL, return cpu_online_mask
>>
>> [1] https://uefi.org/sites/default/files/resources/ACPI_6_3_final_Jan30.pdf
> 
> Similar to David's comment on the sparc patch, these systems don't use
> ACPI so I don't see from your commit message why this change would be
> relevant.
> 
> This same comment applies to patch 9 too.

Thanks for pointing out.

MIPS's NUMA node id is also defined by DT?


> 
> Thanks,
>     Paul
> 
>>
>> Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
>> ---
>>  arch/mips/include/asm/mach-ip27/topology.h | 15 ++++++++++++---
>>  1 file changed, 12 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/mips/include/asm/mach-ip27/topology.h b/arch/mips/include/asm/mach-ip27/topology.h
>> index 965f079..914a55a 100644
>> --- a/arch/mips/include/asm/mach-ip27/topology.h
>> +++ b/arch/mips/include/asm/mach-ip27/topology.h
>> @@ -15,9 +15,18 @@ struct cpuinfo_ip27 {
>>  extern struct cpuinfo_ip27 sn_cpu_info[NR_CPUS];
>>  
>>  #define cpu_to_node(cpu)	(sn_cpu_info[(cpu)].p_nodeid)
>> -#define cpumask_of_node(node)	((node) == -1 ?				\
>> -				 cpu_all_mask :				\
>> -				 &hub_data(node)->h_cpus)
>> +
>> +static inline const struct cpumask *cpumask_of_node(int node)
>> +{
>> +	if (node >= MAX_COMPACT_NODES)
>> +		return cpu_none_mask;
>> +
>> +	if (node < 0 || !hub_data(node))
>> +		return cpu_online_mask;
>> +
>> +	return &hub_data(node)->h_cpus;
>> +}
>> +
>>  struct pci_bus;
>>  extern int pcibus_to_node(struct pci_bus *);
>>  
>> -- 
>> 2.8.1
>>
> 
> .
> 


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Re: [PATCH v2 2/9] x86: numa: check the node id consistently for x86

[Peter Zijlstra]

On Mon, Sep 02, 2019 at 01:46:51PM +0800, Yunsheng Lin wrote:
> On 2019/9/1 0:12, Peter Zijlstra wrote:

> > 1) because even it is not set, the device really does belong to a node.
> > It is impossible a device will have magic uniform access to memory when
> > CPUs cannot.
> 
> So it means dev_to_node() will return either NUMA_NO_NODE or a
> valid node id?

NUMA_NO_NODE := -1, which is not a valid node number. It is also, like I
said, not a valid device location on a NUMA system.

Just because ACPI/BIOS is shit, doesn't mean the device doesn't have a
node association. It just means we don't know and might have to guess.

> > 2) is already true today, cpumask_of_node() requires a valid node_id.
> 
> Ok, most of the user does check node_id before calling
> cpumask_of_node(), but does a little different type of checking:
> 
> 1) some does " < 0" check;
> 2) some does "== NUMA_NO_NODE" check;
> 3) some does ">= MAX_NUMNODES" check;
> 4) some does "< 0 || >= MAX_NUMNODES || !node_online(node)" check.

The one true way is:

	'(unsigned)node_id >= nr_node_ids'

> > 3) is just wrong and increases overhead for everyone.
> 
> Ok, cpumask_of_node() is also used in some critical path such
> as scheduling, which may not need those checking, the overhead
> is unnecessary.
> 
> But for non-critical path such as setup or configuration path,
> it better to have consistent checking, and also simplify the
> user code that calls cpumask_of_node().
> 
> Do you think it is worth the trouble to add a new function
> such as cpumask_of_node_check(maybe some other name) to do
> consistent checking?
> 
> Or caller just simply check if dev_to_node()'s return value is
> NUMA_NO_NODE before calling cpumask_of_node()?

It is not a matter of convenience. The function is called
cpumask_of_node(), when node < 0 || node >= nr_node_ids, it is not a
valid node, therefore the function shouldn't return anything except an
error.

Also note that the CONFIG_DEBUG_PER_CPU_MAPS version of
cpumask_of_node() already does this (although it wants the below fix).

---
diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index e6dad600614c..5f49c10201c7 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -861,7 +861,7 @@ void numa_remove_cpu(int cpu)
  */
 const struct cpumask *cpumask_of_node(int node)
 {
-	if (node >= nr_node_ids) {
+	if ((unsigned)node >= nr_node_ids) {
 		printk(KERN_WARNING
 			"cpumask_of_node(%d): node > nr_node_ids(%u)\n",
 			node, nr_node_ids);

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Re: [PATCH v2 2/9] x86: numa: check the node id consistently for x86

[Yunsheng Lin]

On 2019/9/2 15:25, Peter Zijlstra wrote:
> On Mon, Sep 02, 2019 at 01:46:51PM +0800, Yunsheng Lin wrote:
>> On 2019/9/1 0:12, Peter Zijlstra wrote:
> 
>>> 1) because even it is not set, the device really does belong to a node.
>>> It is impossible a device will have magic uniform access to memory when
>>> CPUs cannot.
>>
>> So it means dev_to_node() will return either NUMA_NO_NODE or a
>> valid node id?
> 
> NUMA_NO_NODE := -1, which is not a valid node number. It is also, like I
> said, not a valid device location on a NUMA system.
> 
> Just because ACPI/BIOS is shit, doesn't mean the device doesn't have a
> node association. It just means we don't know and might have to guess.

How do we guess the device's location when ACPI/BIOS does not set it?

It seems dev_to_node() does not do anything about that and leave the
job to the caller or whatever function that get called with its return
value, such as cpumask_of_node().

> 
>>> 2) is already true today, cpumask_of_node() requires a valid node_id.
>>
>> Ok, most of the user does check node_id before calling
>> cpumask_of_node(), but does a little different type of checking:
>>
>> 1) some does " < 0" check;
>> 2) some does "== NUMA_NO_NODE" check;
>> 3) some does ">= MAX_NUMNODES" check;
>> 4) some does "< 0 || >= MAX_NUMNODES || !node_online(node)" check.
> 
> The one true way is:
> 
> 	'(unsigned)node_id >= nr_node_ids'

I missed the magic of the "unsigned" in your previous reply.

> 
>>> 3) is just wrong and increases overhead for everyone.
>>
>> Ok, cpumask_of_node() is also used in some critical path such
>> as scheduling, which may not need those checking, the overhead
>> is unnecessary.
>>
>> But for non-critical path such as setup or configuration path,
>> it better to have consistent checking, and also simplify the
>> user code that calls cpumask_of_node().
>>
>> Do you think it is worth the trouble to add a new function
>> such as cpumask_of_node_check(maybe some other name) to do
>> consistent checking?
>>
>> Or caller just simply check if dev_to_node()'s return value is
>> NUMA_NO_NODE before calling cpumask_of_node()?
> 
> It is not a matter of convenience. The function is called
> cpumask_of_node(), when node < 0 || node >= nr_node_ids, it is not a
> valid node, therefore the function shouldn't return anything except an
> error.
what do you mean by error? What I can think is three type of errors:
1) return NULL, this way it seems cpumask_of_node() also leave the
   job to the function that calls it.
2) cpu_none_mask, I am not sure what this means, maybe it means there
   is no cpu on the same node with the device?
3) give a warning, stack dump, or even a BUG_ON?

I would prefer the second one, and implement the third one when the
CONFIG_DEBUG_PER_CPU_MAPS is selected.

Any suggestion?

> 
> Also note that the CONFIG_DEBUG_PER_CPU_MAPS version of
> cpumask_of_node() already does this (although it wants the below fix).

Thanks for the note and example.


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Re: [PATCH v2 7/9] sparc64: numa: check the node id consistently for sparc64

[David Miller]

From: Yunsheng Lin <linyunsheng@huawei.com>
Date: Mon, 2 Sep 2019 14:08:31 +0800

> The NUMA node id in sparc64 system is defined by DT semantics?

Sometimes, and in other cases other methods are used to determine
the NUMA node id.

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