lib/genalloc.c: fix overflow of ending address of memory chunk
In struct gen_pool_chunk, end_addr means the end address of memory chunk
(inclusive), but in the implementation it is treated as address + size of
memory chunk (exclusive), so it points to the address plus one instead of
correct ending address.
The ending address of memory chunk plus one will cause overflow on the
memory chunk including the last address of memory map, e.g. when starting
address is 0xFFF00000 and size is 0x100000 on 32bit machine, ending
address will be 0x100000000.
Use correct ending address like starting address + size - 1.
[akpm@linux-foundation.org: add comment to struct gen_pool_chunk:end_addr]
Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
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 b35cfa9..2a39bf6 100644
--- a/lib/genalloc.c
+++ b/lib/genalloc.c
@@ -37,6 +37,11 @@
#include <linux/of_address.h>
#include <linux/of_device.h>
+static inline size_t chunk_size(const struct gen_pool_chunk *chunk)
+{
+ return chunk->end_addr - chunk->start_addr + 1;
+}
+
static int set_bits_ll(unsigned long *addr, unsigned long mask_to_set)
{
unsigned long val, nval;
@@ -188,7 +193,7 @@
chunk->phys_addr = phys;
chunk->start_addr = virt;
- chunk->end_addr = virt + size;
+ chunk->end_addr = virt + size - 1;
atomic_set(&chunk->avail, size);
spin_lock(&pool->lock);
@@ -213,7 +218,7 @@
rcu_read_lock();
list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
- if (addr >= chunk->start_addr && addr < chunk->end_addr) {
+ if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
paddr = chunk->phys_addr + (addr - chunk->start_addr);
break;
}
@@ -242,7 +247,7 @@
chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
list_del(&chunk->next_chunk);
- end_bit = (chunk->end_addr - chunk->start_addr) >> order;
+ end_bit = chunk_size(chunk) >> order;
bit = find_next_bit(chunk->bits, end_bit, 0);
BUG_ON(bit < end_bit);
@@ -283,7 +288,7 @@
if (size > atomic_read(&chunk->avail))
continue;
- end_bit = (chunk->end_addr - chunk->start_addr) >> order;
+ end_bit = chunk_size(chunk) >> order;
retry:
start_bit = pool->algo(chunk->bits, end_bit, start_bit, nbits,
pool->data);
@@ -330,8 +335,8 @@
nbits = (size + (1UL << order) - 1) >> order;
rcu_read_lock();
list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
- if (addr >= chunk->start_addr && addr < chunk->end_addr) {
- BUG_ON(addr + size > chunk->end_addr);
+ if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
+ BUG_ON(addr + size - 1 > chunk->end_addr);
start_bit = (addr - chunk->start_addr) >> order;
remain = bitmap_clear_ll(chunk->bits, start_bit, nbits);
BUG_ON(remain);
@@ -400,7 +405,7 @@
rcu_read_lock();
list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
- size += chunk->end_addr - chunk->start_addr;
+ size += chunk_size(chunk);
rcu_read_unlock();
return size;
}