From: Guenter Roeck <linux@roeck-us.net>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Robin Murphy <robin.murphy@arm.com>,
iommu@lists.linux.dev, linux-kbuild@vger.kernel.org,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Ming Lin <ming.l@ssi.samsung.com>,
Sagi Grimberg <sagi@grimberg.me>
Subject: Re: [PATCH] lib/sg_pool: change module_init(sg_pool_init) to subsys_initcall
Date: Fri, 23 Sep 2022 08:28:09 -0700 [thread overview]
Message-ID: <20220923152809.GA455235@roeck-us.net> (raw)
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@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 <linux@roeck-us.net>
> Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Guenter
next reply other threads:[~2022-09-23 15:28 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-23 15:28 Guenter Roeck [this message]
[not found] <CGME20220923113941eucas1p2e5f7b9bc7316114e69ab6348d40d3b6d@eucas1p2.samsung.com>
2022-09-23 11:38 ` [PATCH] lib/sg_pool: change module_init(sg_pool_init) to subsys_initcall Masahiro Yamada
2022-09-23 11:43 ` Masahiro Yamada
2022-09-23 12:09 ` Robin Murphy
2022-09-23 12:20 ` Marek Szyprowski
2022-09-23 14:49 ` Christoph Hellwig
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