On 2019/9/15 13:49, Mike Rapoport wrote: > Hi, > > On Thu, Sep 12, 2019 at 06:15:33PM +0800, Yunsheng Lin wrote: >> When passing the return value of dev_to_node() to cpumask_of_node() >> without checking the node id if the 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. >> >> Since this arch was already NUMA_NO_NODE aware, this patch only changes >> it to return cpu_online_mask and use NUMA_NO_NODE instead of "-1". >> >> [1] https://lore.kernel.org/patchwork/patch/1125789/ >> Signed-off-by: Yunsheng Lin <linyunsheng@xxxxxxxxxx> >> Suggested-by: Michal Hocko <mhocko@xxxxxxxxxx> >> --- >> 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. >> --- >> arch/mips/include/asm/mach-ip27/topology.h | 4 ++-- > > Nit: the subject says "mips:", but this patch only touches sgi-ip27 and > loongson is updated as a separate patch. I don't see why both patches > cannot be merged. Moreover, the whole set can be made as a single patch, > IMHO. Thanks for reviewing. As this patchset touches a few files, which may has different maintainer. I am not sure if a separate patch for different arch will make the merging process easy, or a single patch will make the merging process easy? It can be made as a single patch if a single patch will make the merging process easy. > >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> 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 *); >> -- >> 2.8.1 >> >
