On 2019/9/17 13:28, Michael Ellerman wrote: > Yunsheng Lin <linyunsh...@huawei.com> writes: >> When passing the return value of dev_to_node() to cpumask_of_node() >> without checking if the device's node id is NUMA_NO_NODE, there is >> global-out-of-bounds detected by KASAN. >> >> From the discussion [1], NUMA_NO_NODE really means no node affinity, >> which also means all cpus should be usable. So the cpumask_of_node() >> should always return all cpus online when user passes the node id as >> NUMA_NO_NODE, just like similar semantic that page allocator handles >> NUMA_NO_NODE. >> >> But we cannot really copy the page allocator logic. Simply because the >> page allocator doesn't enforce the near node affinity. It just picks it >> up as a preferred node but then it is free to fallback to any other numa >> node. This is not the case here and node_to_cpumask_map will only restrict >> to the particular node's cpus which would have really non deterministic >> behavior depending on where the code is executed. So in fact we really >> want to return cpu_online_mask for NUMA_NO_NODE. >> >> Some arches were already NUMA_NO_NODE aware, but they return cpu_all_mask, >> which should be identical with cpu_online_mask when those arches do not >> support cpu hotplug, this patch also changes them to return cpu_online_mask >> in order to be consistent and use NUMA_NO_NODE instead of "-1". > > Except some of those arches *do* support CPU hotplug, powerpc and sparc > at least. So switching from cpu_all_mask to cpu_online_mask is a > meaningful change.
Yes, thanks for pointing out. > > That doesn't mean it's wrong, but you need to explain why it's the right > change. How about adding the below to the commit log: Even if some of the arches do support CPU hotplug, it does not make sense to return the cpu that has been hotplugged. Any suggestion? > > >> Also there is a debugging version of node_to_cpumask_map() for x86 and >> arm64, which is only used when CONFIG_DEBUG_PER_CPU_MAPS is defined, this >> patch changes it to handle NUMA_NO_NODE as normal node_to_cpumask_map(). >> >> [1] https://lore.kernel.org/patchwork/patch/1125789/ >> Signed-off-by: Yunsheng Lin <linyunsh...@huawei.com> >> Suggested-by: Michal Hocko <mho...@kernel.org> >> Acked-by: Michal Hocko <mho...@suse.com> >> --- >> V5: Drop unsigned "fix" change for x86/arm64, and change comment log >> according to Michal's comment. >> V4: Have all these changes in a single patch. > > This makes it much harder to get the patch merged, you basically have to > get Andrew Morton to merge it now. Sending individual patches for each > arch means each arch maintainer can merge them separately. I am new to the arch change here, and not sure which is the best way to get the multi-arches change merged. Do you think it is better to resend this as individual patches for each arch after megre window? thanks for reviewing. > > cheers > >> V3: Change to only handle NUMA_NO_NODE, and return cpu_online_mask >> for NUMA_NO_NODE case, and change the commit log to better justify >> the change. >> V2: make the node id checking change to other arches too. >> --- >> arch/alpha/include/asm/topology.h | 2 +- >> arch/arm64/include/asm/numa.h | 3 +++ >> arch/arm64/mm/numa.c | 3 +++ >> arch/mips/include/asm/mach-ip27/topology.h | 4 ++-- >> arch/mips/include/asm/mach-loongson64/topology.h | 4 +++- >> arch/powerpc/include/asm/topology.h | 6 +++--- >> arch/s390/include/asm/topology.h | 3 +++ >> arch/sparc/include/asm/topology_64.h | 6 +++--- >> arch/x86/include/asm/topology.h | 3 +++ >> arch/x86/mm/numa.c | 3 +++ >> 10 files changed, 27 insertions(+), 10 deletions(-) >> >> diff --git a/arch/alpha/include/asm/topology.h >> b/arch/alpha/include/asm/topology.h >> index 5a77a40..836c9e2 100644 >> --- a/arch/alpha/include/asm/topology.h >> +++ b/arch/alpha/include/asm/topology.h >> @@ -31,7 +31,7 @@ static const struct cpumask *cpumask_of_node(int node) >> int cpu; >> >> if (node == NUMA_NO_NODE) >> - return cpu_all_mask; >> + return cpu_online_mask; >> >> cpumask_clear(&node_to_cpumask_map[node]); >> >> diff --git a/arch/arm64/include/asm/numa.h b/arch/arm64/include/asm/numa.h >> index 626ad01..c8a4b31 100644 >> --- a/arch/arm64/include/asm/numa.h >> +++ b/arch/arm64/include/asm/numa.h >> @@ -25,6 +25,9 @@ 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 == NUMA_NO_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..f57202d 100644 >> --- a/arch/arm64/mm/numa.c >> +++ b/arch/arm64/mm/numa.c >> @@ -46,6 +46,9 @@ EXPORT_SYMBOL(node_to_cpumask_map); >> */ >> const struct cpumask *cpumask_of_node(int node) >> { >> + if (node == NUMA_NO_NODE) >> + return cpu_online_mask; >> + >> if (WARN_ON(node >= nr_node_ids)) >> return cpu_none_mask; >> >> diff --git a/arch/mips/include/asm/mach-ip27/topology.h >> b/arch/mips/include/asm/mach-ip27/topology.h >> index 965f079..04505e6 100644 >> --- a/arch/mips/include/asm/mach-ip27/topology.h >> +++ b/arch/mips/include/asm/mach-ip27/topology.h >> @@ -15,8 +15,8 @@ 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 : \ >> +#define cpumask_of_node(node) ((node) == NUMA_NO_NODE ? >> \ >> + cpu_online_mask : \ >> &hub_data(node)->h_cpus) >> struct pci_bus; >> extern int pcibus_to_node(struct pci_bus *); >> diff --git a/arch/mips/include/asm/mach-loongson64/topology.h >> b/arch/mips/include/asm/mach-loongson64/topology.h >> index 7ff819a..e78daa6 100644 >> --- a/arch/mips/include/asm/mach-loongson64/topology.h >> +++ b/arch/mips/include/asm/mach-loongson64/topology.h >> @@ -5,7 +5,9 @@ >> #ifdef CONFIG_NUMA >> >> #define cpu_to_node(cpu) (cpu_logical_map(cpu) >> 2) >> -#define cpumask_of_node(node) (&__node_data[(node)]->cpumask) >> +#define cpumask_of_node(node) ((node) == NUMA_NO_NODE ? >> \ >> + cpu_online_mask : \ >> + &__node_data[(node)]->cpumask) >> >> struct pci_bus; >> extern int pcibus_to_node(struct pci_bus *); >> diff --git a/arch/powerpc/include/asm/topology.h >> b/arch/powerpc/include/asm/topology.h >> index 2f7e1ea..309f847 100644 >> --- a/arch/powerpc/include/asm/topology.h >> +++ b/arch/powerpc/include/asm/topology.h >> @@ -17,9 +17,9 @@ struct device_node; >> >> #include <asm/mmzone.h> >> >> -#define cpumask_of_node(node) ((node) == -1 ? >> \ >> - cpu_all_mask : \ >> - node_to_cpumask_map[node]) >> +#define cpumask_of_node(node) ((node) == NUMA_NO_NODE ? >> \ >> + cpu_online_mask : \ >> + node_to_cpumask_map[node]) >> >> struct pci_bus; >> #ifdef CONFIG_PCI >> diff --git a/arch/s390/include/asm/topology.h >> b/arch/s390/include/asm/topology.h >> index cca406f..1bd2e73 100644 >> --- a/arch/s390/include/asm/topology.h >> +++ b/arch/s390/include/asm/topology.h >> @@ -78,6 +78,9 @@ 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 == NUMA_NO_NODE) >> + return cpu_online_mask; >> + >> return &node_to_cpumask_map[node]; >> } >> >> diff --git a/arch/sparc/include/asm/topology_64.h >> b/arch/sparc/include/asm/topology_64.h >> index 34c628a..8c29357 100644 >> --- a/arch/sparc/include/asm/topology_64.h >> +++ b/arch/sparc/include/asm/topology_64.h >> @@ -11,9 +11,9 @@ 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]) >> +#define cpumask_of_node(node) ((node) == NUMA_NO_NODE ? >> \ >> + cpu_online_mask : \ >> + &numa_cpumask_lookup_table[node]) >> >> struct pci_bus; >> #ifdef CONFIG_PCI >> diff --git a/arch/x86/include/asm/topology.h >> b/arch/x86/include/asm/topology.h >> index 4b14d23..7fa82e1 100644 >> --- a/arch/x86/include/asm/topology.h >> +++ b/arch/x86/include/asm/topology.h >> @@ -69,6 +69,9 @@ 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 == NUMA_NO_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..84b28ef 100644 >> --- a/arch/x86/mm/numa.c >> +++ b/arch/x86/mm/numa.c >> @@ -861,6 +861,9 @@ void numa_remove_cpu(int cpu) >> */ >> const struct cpumask *cpumask_of_node(int node) >> { >> + if (node == NUMA_NO_NODE) >> + return cpu_online_mask; >> + >> if (node >= nr_node_ids) { >> printk(KERN_WARNING >> "cpumask_of_node(%d): node > nr_node_ids(%u)\n", >> -- >> 2.8.1 > > . >
