If "pool_id" is negative then it leads to a read before the start of the array. If "cli_id" is out of bounds then it leads to a NULL dereference of "cli". GCC would have warned about that bug except that we initialized the warning message away. Also it's better to put the parameter names into the function declaration in the .h file. It serves as a kind of documentation. Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> --- BTW, This file has a ton of GCC warnings. This function returns -1 on error which is a nonsense return code but the return value is not checked anyway. *Grumble*. diff --git a/drivers/staging/ramster/zcache.h b/drivers/staging/ramster/zcache.h index c59666e..81722b3 100644 --- a/drivers/staging/ramster/zcache.h +++ b/drivers/staging/ramster/zcache.h @@ -42,7 +42,7 @@ extern void zcache_decompress_to_page(char *, unsigned int, struct page *); #ifdef CONFIG_RAMSTER extern void *zcache_pampd_create(char *, unsigned int, bool, int, struct tmem_handle *); -extern int zcache_autocreate_pool(int, int, bool); +int zcache_autocreate_pool(unsigned int cli_id, unsigned int pool_id, bool eph); #endif #define MAX_POOLS_PER_CLIENT 16 diff --git a/drivers/staging/ramster/zcache-main.c b/drivers/staging/ramster/zcache-main.c index 24b3d4a..86e19d6 100644 --- a/drivers/staging/ramster/zcache-main.c +++ b/drivers/staging/ramster/zcache-main.c @@ -1338,10 +1338,10 @@ static int zcache_local_new_pool(uint32_t flags) return zcache_new_pool(LOCAL_CLIENT, flags); } -int zcache_autocreate_pool(int cli_id, int pool_id, bool eph) +int zcache_autocreate_pool(unsigned int cli_id, unsigned int pool_id, bool eph) { struct tmem_pool *pool; - struct zcache_client *cli = NULL; + struct zcache_client *cli; uint32_t flags = eph ? 0 : TMEM_POOL_PERSIST; int ret = -1; @@ -1350,8 +1350,10 @@ int zcache_autocreate_pool(int cli_id, int pool_id, bool eph) goto out; if (pool_id >= MAX_POOLS_PER_CLIENT) goto out; - else if ((unsigned int)cli_id < MAX_CLIENTS) - cli = &zcache_clients[cli_id]; + if (cli_id >= MAX_CLIENTS) + goto out; + + cli = &zcache_clients[cli_id]; if ((eph && disable_cleancache) || (!eph && disable_frontswap)) { pr_err("zcache_autocreate_pool: pool type disabled\n"); goto out; -- To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html