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lib/sg_pool: change module_init(sg_pool_init) to subsys_initcall

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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 9b1d6c8950 ("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: 9b1d6c8950 ("lib: scatterlist: move SG pool code from SCSI driver to lib/sg_pool.c")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Masahiro Yamada 2022-09-23 20:38:35 +09:00 committed by Christoph Hellwig
parent 91fd38ea75
commit f7f04d1983
1 changed files with 2 additions and 14 deletions
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16
lib/sg_pool.c
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@ -1,5 +1,5 @@
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/module.h>
#include <linux/init.h>
#include <linux/scatterlist.h>
#include <linux/mempool.h>
#include <linux/slab.h>
@ -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);