On 2019/9/15 14:46, Mike Rapoport wrote: > On Sun, Sep 15, 2019 at 02:13:51PM +0800, Yunsheng Lin wrote: >> 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? > > The set makes the same logical change to several definitions of > cpumask_of_node(). It's appropriate to have all these changes in a single > patch. Ok, thanks. Will have all these changes in a single patch. > >> 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 >>>> >>> >> >
