On Fri, Sep 23, 2022 at 08:38:35PM +0900, Masahiro Yamada wrote: > 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 Kbuild 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 fragine. > > 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@xxxxxxxxxxxx/ > Link: https://lore.kernel.org/all/8e70837d-d859-dfb2-bf7f-83f8b31467bc@xxxxxxxxxxx/ > Fixes: 9b1d6c895002 ("lib: scatterlist: move SG pool code from SCSI driver to lib/sg_pool.c") > Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx> > Reported-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> > Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx> Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx> Guenter