lib/genalloc: fix the overflow when size is too big

Some graphic card has very big memory on chip, such as 32G bytes.

In the following case, it will cause overflow:

    pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE);
    ret = gen_pool_add(pool, 0x1000000, SZ_32G, NUMA_NO_NODE);

    va = gen_pool_alloc(pool, SZ_4G);

The overflow occurs in gen_pool_alloc_algo_owner():

		....
		size = nbits << order;
		....

The @nbits is "int" type, so it will overflow.
Then the gen_pool_avail() will return the wrong value.

This patch converts some "int" to "unsigned long", and
changes the compare code in while.

Link: https://lkml.kernel.org/r/20201229060657.3389-1-sjhuang@iluvatar.ai
Signed-off-by: Huang Shijie <sjhuang@iluvatar.ai>
Reported-by: Shi Jiasheng <jiasheng.shi@iluvatar.ai>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/lib/genalloc.c b/lib/genalloc.c
index 7f1244b..dab97bb 100644 (file)
--- a/lib/genalloc.c
+++ b/lib/genalloc.c
@@ -81,14 +81,14 @@ static int clear_bits_ll(unsigned long *addr, unsigned long mask_to_clear)
  * users set the same bit, one user will return remain bits, otherwise
  * return 0.
  */
-static int bitmap_set_ll(unsigned long *map, int start, int nr)
+static int bitmap_set_ll(unsigned long *map, unsigned long start, unsigned long nr)
 {
        unsigned long *p = map + BIT_WORD(start);
-       const int size = start + nr;
+       const unsigned long size = start + nr;
        int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
        unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
 
-       while (nr - bits_to_set >= 0) {
+       while (nr >= bits_to_set) {
                if (set_bits_ll(p, mask_to_set))
                        return nr;
                nr -= bits_to_set;
@@ -116,14 +116,15 @@ static int bitmap_set_ll(unsigned long *map, int start, int nr)
  * users clear the same bit, one user will return remain bits,
  * otherwise return 0.
  */
-static int bitmap_clear_ll(unsigned long *map, int start, int nr)
+static unsigned long
+bitmap_clear_ll(unsigned long *map, unsigned long start, unsigned long nr)
 {
        unsigned long *p = map + BIT_WORD(start);
-       const int size = start + nr;
+       const unsigned long size = start + nr;
        int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
        unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
 
-       while (nr - bits_to_clear >= 0) {
+       while (nr >= bits_to_clear) {
                if (clear_bits_ll(p, mask_to_clear))
                        return nr;
                nr -= bits_to_clear;
@@ -183,8 +184,8 @@ int gen_pool_add_owner(struct gen_pool *pool, unsigned long virt, phys_addr_t ph
                 size_t size, int nid, void *owner)
 {
        struct gen_pool_chunk *chunk;
-       int nbits = size >> pool->min_alloc_order;
-       int nbytes = sizeof(struct gen_pool_chunk) +
+       unsigned long nbits = size >> pool->min_alloc_order;
+       unsigned long nbytes = sizeof(struct gen_pool_chunk) +
                                BITS_TO_LONGS(nbits) * sizeof(long);
 
        chunk = vzalloc_node(nbytes, nid);
@@ -242,7 +243,7 @@ void gen_pool_destroy(struct gen_pool *pool)
        struct list_head *_chunk, *_next_chunk;
        struct gen_pool_chunk *chunk;
        int order = pool->min_alloc_order;
-       int bit, end_bit;
+       unsigned long bit, end_bit;
 
        list_for_each_safe(_chunk, _next_chunk, &pool->chunks) {
                chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
@@ -278,7 +279,7 @@ unsigned long gen_pool_alloc_algo_owner(struct gen_pool *pool, size_t size,
        struct gen_pool_chunk *chunk;
        unsigned long addr = 0;
        int order = pool->min_alloc_order;
-       int nbits, start_bit, end_bit, remain;
+       unsigned long nbits, start_bit, end_bit, remain;
 
 #ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
        BUG_ON(in_nmi());
@@ -487,7 +488,7 @@ void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr, size_t size,
 {
        struct gen_pool_chunk *chunk;
        int order = pool->min_alloc_order;
-       int start_bit, nbits, remain;
+       unsigned long start_bit, nbits, remain;
 
 #ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
        BUG_ON(in_nmi());
@@ -755,7 +756,7 @@ unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
        index = bitmap_find_next_zero_area(map, size, start, nr, 0);
 
        while (index < size) {
-               int next_bit = find_next_bit(map, size, index + nr);
+               unsigned long next_bit = find_next_bit(map, size, index + nr);
                if ((next_bit - index) < len) {
                        len = next_bit - index;
                        start_bit = index;