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. > 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 > >> > > > -- Sincerely yours, Mike.
