From: "Mike Rapoport (Microsoft)" rppt@kernel.org
The memory allocated for the ROX cache was removed from the direct map to reduce amount of direct map updates, however this cannot be tolerated by /proc/kcore that accesses module memory using vread_iter() and the latter does vmalloc_to_page() and copy_page_to_iter_nofault().
Instead of removing ROX cache memory from the direct map and mapping it as ROX in vmalloc space, simply call set_memory_rox() that will take care of proper permissions on both vmalloc and in the direct map.
Signed-off-by: Mike Rapoport (Microsoft) rppt@kernel.org --- mm/execmem.c | 17 ++++------------- 1 file changed, 4 insertions(+), 13 deletions(-)
diff --git a/mm/execmem.c b/mm/execmem.c index 317b6a8d35be..04b0bf1b5025 100644 --- a/mm/execmem.c +++ b/mm/execmem.c @@ -257,7 +257,6 @@ static void *__execmem_cache_alloc(struct execmem_range *range, size_t size) static int execmem_cache_populate(struct execmem_range *range, size_t size) { unsigned long vm_flags = VM_ALLOW_HUGE_VMAP; - unsigned long start, end; struct vm_struct *vm; size_t alloc_size; int err = -ENOMEM; @@ -275,26 +274,18 @@ static int execmem_cache_populate(struct execmem_range *range, size_t size) /* fill memory with instructions that will trap */ execmem_fill_trapping_insns(p, alloc_size, /* writable = */ true);
- start = (unsigned long)p; - end = start + alloc_size; - - vunmap_range(start, end); - - err = execmem_set_direct_map_valid(vm, false); - if (err) - goto err_free_mem; - - err = vmap_pages_range_noflush(start, end, range->pgprot, vm->pages, - PMD_SHIFT); + err = set_memory_rox((unsigned long)p, vm->nr_pages); if (err) goto err_free_mem;
err = execmem_cache_add(p, alloc_size); if (err) - goto err_free_mem; + goto err_reset_direct_map;
return 0;
+err_reset_direct_map: + execmem_set_direct_map_valid(vm, true); err_free_mem: vfree(p); return err;