Hi Luis,
On Fri, Jan 15, 2016 at 03:42:17PM -0800, Luis R. Rodriguez wrote:
> From: "Luis R. Rodriguez" <mcgrof@xxxxxxxx>
>
> Commit f2411da746985 ("driver-core: add driver module
> asynchronous probe support") added async probe support,
> in two forms:
>
> * in-kernel driver specification annotation
> * generic async_probe module parameter (modprobe foo async_probe)
>
> To support the generic kernel parameter parse_args() was
> extended via commit ecc8617053e0 ("module: add extra
> argument for parse_params() callback") however commit
> failed to f2411da746985 failed to add the required argument.
>
> This causes a crash then whenever async_probe generic
> module parameter is used. This was overlooked when the
> form in which in-kernel async probe support was reworked
> a bit... Fix this as originally intended.
>
> Cc: Hannes Reinecke <hare@xxxxxxx>
> Cc: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx (4.2+)
> Signed-off-by: Luis R. Rodriguez <mcgrof@xxxxxxxx>
> ---
>
> Resending and addressing Rusty, the other patch I sent on Dec 19
> was addressed to Greg by mistake. Sorry about that.
>
> kernel/module.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/module.c b/kernel/module.c
> index 8f051a106676..88100ea77c55 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -3402,16 +3402,22 @@ out:
> static int unknown_module_param_cb(char *param, char *val, const char *modname,
> void *arg)
> {
> - struct module *mod = arg;
> + struct module *mod;
> int ret;
>
> if (strcmp(param, "async_probe") == 0) {
> + mod = arg;
> + if (!mod) {
> + ret = -ENOENT;
> + goto out;
> + }
Why do we need this chunk? We only call unknown_module_param_cb() from
one place and with your chunk below we do know that "mod" is never NULL.
> mod->async_probe_requested = true;
> return 0;
> }
>
> /* Check for magic 'dyndbg' arg */
> ret = ddebug_dyndbg_module_param_cb(param, val, modname);
> +out:
> if (ret != 0)
> pr_warn("%s: unknown parameter '%s' ignored\n", modname, param);
> return 0;
> @@ -3515,7 +3521,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
>
> /* Module is ready to execute: parsing args may do that. */
> after_dashes = parse_args(mod->name, mod->args, mod->kp, mod->num_kp,
> - -32768, 32767, NULL,
> + -32768, 32767, mod,
I believe this is the only change that is needed.
> unknown_module_param_cb);
> if (IS_ERR(after_dashes)) {
> err = PTR_ERR(after_dashes);
> --
> 2.6.2
>
Thanks.
--
Dmitry
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