From f7f04d198334d6f69c76c8f8675194551a3da574 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Fri, 23 Sep 2022 20:38:35 +0900 Subject: [PATCH] lib/sg_pool: change module_init(sg_pool_init) to subsys_initcall sg_alloc_table_chained() is called by several drivers, but if it is called before sg_pool_init(), it results in a NULL pointer dereference in sg_pool_alloc(). Since commit 9b1d6c895002 ("lib: scatterlist: move SG pool code from SCSI driver to lib/sg_pool.c"), we rely on module_init(sg_pool_init) is invoked before other module_init calls but this assumption is fragile. I slightly changed the link order while refactoring Kbuild, then uncovered this issue. I should keep the current link order, but depending on a specific call order among module_init is so fragile. We usually define the init order by specifying *_initcall correctly, or delay the driver probing by returning -EPROBE_DEFER. Change module_initcall() to subsys_initcall(), and also delete the pointless module_exit() because lib/sg_pool.c is always compiled as built-in. (CONFIG_SG_POOL is bool) Link: https://lore.kernel.org/all/20220921043946.GA1355561@roeck-us.net/ Link: https://lore.kernel.org/all/8e70837d-d859-dfb2-bf7f-83f8b31467bc@samsung.com/ Fixes: 9b1d6c895002 ("lib: scatterlist: move SG pool code from SCSI driver to lib/sg_pool.c") Reported-by: Guenter Roeck Reported-by: Marek Szyprowski Signed-off-by: Masahiro Yamada Reviewed-by: Robin Murphy Tested-by: Marek Szyprowski Signed-off-by: Christoph Hellwig --- lib/sg_pool.c | 16 ++-------------- 1 file changed, 2 insertions(+), 14 deletions(-) diff --git a/lib/sg_pool.c b/lib/sg_pool.c index a0b1a52cd6f7..9bfe60ca3f37 100644 --- a/lib/sg_pool.c +++ b/lib/sg_pool.c @@ -1,5 +1,5 @@ // SPDX-License-Identifier: GPL-2.0-only -#include +#include #include #include #include @@ -177,16 +177,4 @@ cleanup_sdb: return -ENOMEM; } -static __exit void sg_pool_exit(void) -{ - int i; - - for (i = 0; i < SG_MEMPOOL_NR; i++) { - struct sg_pool *sgp = sg_pools + i; - mempool_destroy(sgp->pool); - kmem_cache_destroy(sgp->slab); - } -} - -module_init(sg_pool_init); -module_exit(sg_pool_exit); +subsys_initcall(sg_pool_init);