Hello Omer Shpigelman,
The patch 0feaf86d4e69: "habanalabs: add virtual memory and MMU
modules" from Feb 16, 2019, leads to the following static checker
warning:
drivers/misc/habanalabs/memory.c:96 alloc_device_memory()
warn: integer overflows '(args->alloc.mem_size + (page_size - 1)) >>
page_shift'
drivers/misc/habanalabs/memory.c
53 static int alloc_device_memory(struct hl_ctx *ctx, struct hl_mem_in
*args,
54 u32 *ret_handle)
55 {
56 struct hl_device *hdev = ctx->hdev;
57 struct hl_vm *vm = &hdev->vm;
58 struct hl_vm_phys_pg_pack *phys_pg_pack;
59 u64 paddr = 0;
60 u32 total_size, num_pgs, num_curr_pgs, page_size, page_shift;
61 int handle, rc, i;
62 bool contiguous;
63
64 num_curr_pgs = 0;
65 page_size = hdev->asic_prop.dram_page_size;
66 page_shift = __ffs(page_size);
67 num_pgs = (args->alloc.mem_size + (page_size - 1)) >> page_shift;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This addition can have an integer overflow. mem_size is a u64 that
comes from the user in the IOCTL. Also num_pgs is a u32 so it can't
hold mem_size / 4096.
68 total_size = num_pgs << page_shift;
^^^^^^^^^^^^^^^^^^^^^
So can this shift. total_size is u32.
69
70 contiguous = args->flags & HL_MEM_CONTIGUOUS;
71
72 if (contiguous) {
73 paddr = (u64) gen_pool_alloc(vm->dram_pg_pool, total_size);
74 if (!paddr) {
75 dev_err(hdev->dev,
76 "failed to allocate %u huge contiguous pages\n",
77 num_pgs);
78 return -ENOMEM;
79 }
80 }
81
82 phys_pg_pack = kzalloc(sizeof(*phys_pg_pack), GFP_KERNEL);
83 if (!phys_pg_pack) {
84 rc = -ENOMEM;
85 goto pages_pack_err;
86 }
87
88 phys_pg_pack->vm_type = VM_TYPE_PHYS_PACK;
89 phys_pg_pack->asid = ctx->asid;
90 phys_pg_pack->npages = num_pgs;
91 phys_pg_pack->page_size = page_size;
92 phys_pg_pack->total_size = total_size;
93 phys_pg_pack->flags = args->flags;
94 phys_pg_pack->contiguous = contiguous;
95
--> 96 phys_pg_pack->pages = kcalloc(num_pgs, sizeof(u64), GFP_KERNEL);
^^^^^^^
We allocate less memory than intended.
97 if (!phys_pg_pack->pages) {
98 rc = -ENOMEM;
99 goto pages_arr_err;
100 }
101
102 if (phys_pg_pack->contiguous) {
103 for (i = 0 ; i < num_pgs ; i++)
104 phys_pg_pack->pages[i] = paddr + i * page_size;
105 } else {
regards,
dan carpenter
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