From: Huang Shijie <sjhuang@xxxxxxxxxxx> Subject: 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@xxxxxxxxxxx Signed-off-by: Huang Shijie <sjhuang@xxxxxxxxxxx> Reported-by: Shi Jiasheng <jiasheng.shi@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/genalloc.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) --- a/lib/genalloc.c~lib-genalloc-fix-the-overflow-when-size-is-too-big +++ a/lib/genalloc.c @@ -81,14 +81,14 @@ static int clear_bits_ll(unsigned long * * 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 * * 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 * 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 *p 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_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 { 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 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; _
