2009-03-02 00:45:43

by Rusty Russell

Subject: Re: Command line parameter not passed to module in linux-next

On Saturday 28 February 2009 03:31:05 Christof Schmitt wrote:
> The linux-next kernel does not pass charp parameters from the kernel
> command line to modules:
>
> # cat /proc/cmdline
> dasd=4d70-4d73 root=/dev/dasdc1 zfcp.device=0.0.181d,0x500507630310c562,0x401040C300000000 zfcp.dbfsize=4096 BOOT_IMAGE=0
>
> # cat /sys/module/zfcp/parameters/device
> <NULL>

Thanks:

param: fix charp parameters set via sysfs: FIX

We can't kmalloc at early cmdline parsing.

Reported-by: Christof Schmitt <[email protected]>
Signed-off-by: Rusty Russell <[email protected]>

diff --git a/kernel/params.c b/kernel/params.c
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -223,10 +223,16 @@ int param_set_charp(const char *val, str
if (kp->perm & KPARAM_KMALLOCED)
kfree(*(char **)kp->arg);

- kp->perm |= KPARAM_KMALLOCED;
- *(char **)kp->arg = kstrdup(val, GFP_KERNEL);
- if (!kp->arg)
- return -ENOMEM;
+ /* This is a hack. We can't need to strdup in early boot, and we
+ * don't need to; this mangled commandline is preserved. */
+ if (slab_is_available()) {
+ kp->perm |= KPARAM_KMALLOCED;
+ *(char **)kp->arg = kstrdup(val, GFP_KERNEL);
+ if (!kp->arg)
+ return -ENOMEM;
+ } else
+ *(const char **)kp->arg = val;
+
return 0;
}

2009-03-02 08:38:28

by Christof Schmitt

Subject: Re: Command line parameter not passed to module in linux-next

Rusty Russell <[email protected]> wrote on 03/02/2009 01:45:23 AM:

> On Saturday 28 February 2009 03:31:05 Christof Schmitt wrote:
> > The linux-next kernel does not pass charp parameters from the kernel
> > command line to modules:
> >
> > # cat /proc/cmdline
> > dasd=4d70-4d73 root=/dev/dasdc1 zfcp.device=0.0.181d,
> 0x500507630310c562,0x401040C300000000 zfcp.dbfsize=4096 BOOT_IMAGE=0
> >
> > # cat /sys/module/zfcp/parameters/device
> > <NULL>
>
> Thanks:
>
> param: fix charp parameters set via sysfs: FIX
>
> We can't kmalloc at early cmdline parsing.
>
> Reported-by: Christof Schmitt <[email protected]>
> Signed-off-by: Rusty Russell <[email protected]>
>
> diff --git a/kernel/params.c b/kernel/params.c
> --- a/kernel/params.c
> +++ b/kernel/params.c
> @@ -223,10 +223,16 @@ int param_set_charp(const char *val, str
> if (kp->perm & KPARAM_KMALLOCED)
> kfree(*(char **)kp->arg);
>
> - kp->perm |= KPARAM_KMALLOCED;
> - *(char **)kp->arg = kstrdup(val, GFP_KERNEL);
> - if (!kp->arg)
> - return -ENOMEM;
> + /* This is a hack. We can't need to strdup in early boot, and we
> + * don't need to; this mangled commandline is preserved. */
> + if (slab_is_available()) {
> + kp->perm |= KPARAM_KMALLOCED;
> + *(char **)kp->arg = kstrdup(val, GFP_KERNEL);
> + if (!kp->arg)
> + return -ENOMEM;
> + } else
> + *(const char **)kp->arg = val;
> +
> return 0;
> }

Thanks, the patch works for me.
Tested-by: Christof Schmitt <[email protected]>

--
Christof Schmitt