The problem presented here is related to NUMA systems and tag-based KASAN mode. Getting to it can be explained in the following points: 1. A new chunk is created with pcpu_create_chunk() and vm_structs are allocated. On systems with one NUMA node only one is allocated, but with more NUMA nodes at least a second one will be allocated too. 2. chunk->base_addr is assigned the modified value of vms[0]->addr and thus inherits the tag of this allocated structure. 3. In pcpu_alloc() for each possible cpu pcpu_chunk_addr() is executed which calculates per cpu pointers that correspond to the vms structure addresses. The calculations are based on adding an offset from a table to chunk->base_addr. Here the problem presents itself since for addresses based on vms[1] and up, the tag will be different than the ones based on vms[0] (base_addr). The tag mismatch happens and an error is reported. Reset the base_addr tag, since it will disable tag checks for pointers derived arithmetically from base_addr that would inherit its tag. Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@xxxxxxxxx> --- mm/percpu-vm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c index cd69caf6aa8d..e13750d804f7 100644 --- a/mm/percpu-vm.c +++ b/mm/percpu-vm.c @@ -347,7 +347,7 @@ static struct pcpu_chunk *pcpu_create_chunk(gfp_t gfp) } chunk->data = vms; - chunk->base_addr = vms[0]->addr - pcpu_group_offsets[0]; + chunk->base_addr = kasan_reset_tag(vms[0]->addr) - pcpu_group_offsets[0]; pcpu_stats_chunk_alloc(); trace_percpu_create_chunk(chunk->base_addr); -- 2.47.1
