On Fri, Jan 25, 2019 at 10:30:59AM +0800, Yang Yingliang wrote:
> When we excute the following commands, we got oops
> rmmod ipmi_si
> cat /proc/ioports
>
snip...
>
> If io_setup is called successful in try_smi_init() but try_smi_init()
> goes out_err before calling ipmi_register_smi(), so ipmi_unregister_smi()
> will not be called while removing module. It leads to the resource that
> allocated in io_setup() can not be freed, but the name(DEVICE_NAME) of
> resource is freed while removing the module. It causes use-after-free
> when cat /proc/ioports.
>
> Fix this by calling shutdown_smi() while removing the module and don't
> call release_region() if request_region() is not called to avoid error
> prints.
>
> Fixes: 93c303d2045b ("ipmi_si: Clean up shutdown a bit")
> Cc: stable@xxxxxxxxxxxxxxx
> Reported-by: NuoHan Qiao <qiaonuohan@xxxxxxxxxx>
> Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
> ---
> drivers/char/ipmi/ipmi_si_intf.c | 2 ++
> drivers/char/ipmi/ipmi_si_port_io.c | 3 +++
> 2 files changed, 5 insertions(+)
>
> diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
> index dc8603d..635e98a 100644
> --- a/drivers/char/ipmi/ipmi_si_intf.c
> +++ b/drivers/char/ipmi/ipmi_si_intf.c
> @@ -2235,6 +2235,8 @@ static void cleanup_one_si(struct smi_info *smi_info)
>
> if (smi_info->intf)
> ipmi_unregister_smi(smi_info->intf);
> + else
> + shutdown_smi(smi_info);
This is completely the wrong way to fix this. The general principle is
that a function cleans up for itself if it returns an error. If you
add hacks other places for a function failing you end up with a mess.
I think the right way to fix this is to add something like:
if (rv && new_smi->io.io_size && smi_info->io.io_cleanup) {
smi_info->io.io_cleanup(&smi_info->io);
smi_info->io.io_cleanup = NULL;
}
at the end of try_smi_init().
-corey
>
> if (smi_info->pdev) {
> if (smi_info->pdev_registered)
> diff --git a/drivers/char/ipmi/ipmi_si_port_io.c b/drivers/char/ipmi/ipmi_si_port_io.c
> index ef6dffc..0c46a3f 100644
> --- a/drivers/char/ipmi/ipmi_si_port_io.c
> +++ b/drivers/char/ipmi/ipmi_si_port_io.c
> @@ -53,6 +53,9 @@ static void port_cleanup(struct si_sm_io *io)
> unsigned int addr = io->addr_data;
> int idx;
>
> + if (io->regsize != 1 && io->regsize != 2 && io->regsize != 4)
> + return;
> +
> if (addr) {
> for (idx = 0; idx < io->io_size; idx++)
> release_region(addr + idx * io->regspacing,
> --
> 1.8.3
>
>
