[PATCH] ramoops: update parameters only after successful init

[PATCH] ramoops: update parameters only after successful init

[Kees Cook]

If a platform device exists on the system, but ramoops fails to attach to
it, the module parameters are overridden before ramoops can fall back and
try to use passed module parameters. Move update to end of init routine.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/char/ramoops.c |   17 +++++++++--------
 1 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/char/ramoops.c b/drivers/char/ramoops.c
index 810aff9..0ec4bb3 100644
--- a/drivers/char/ramoops.c
+++ b/drivers/char/ramoops.c
@@ -147,14 +147,6 @@ static int __init ramoops_probe(struct platform_device *pdev)
 	cxt->phys_addr = pdata->mem_address;
 	cxt->record_size = pdata->record_size;
 	cxt->dump_oops = pdata->dump_oops;
-	/*
-	 * Update the module parameter variables as well so they are visible
-	 * through /sys/module/ramoops/parameters/
-	 */
-	mem_size = pdata->mem_size;
-	mem_address = pdata->mem_address;
-	record_size = pdata->record_size;
-	dump_oops = pdata->dump_oops;
 
 	if (!request_mem_region(cxt->phys_addr, cxt->size, "ramoops")) {
 		pr_err("request mem region failed\n");
@@ -175,6 +167,15 @@ static int __init ramoops_probe(struct platform_device *pdev)
 		goto fail1;
 	}
 
+	/*
+	 * Update the module parameter variables as well so they are visible
+	 * through /sys/module/ramoops/parameters/
+	 */
+	mem_size = pdata->mem_size;
+	mem_address = pdata->mem_address;
+	record_size = pdata->record_size;
+	dump_oops = pdata->dump_oops;
+
 	return 0;
 
 fail1:
-- 
1.7.5.4


-- 
Kees Cook                                            @outflux.net

Re: [PATCH] ramoops: update parameters only after successful init

[Andrew Morton]

On Tue, 18 Oct 2011 11:01:27 -0700
Kees Cook <kees@outflux.net> wrote:

> If a platform device exists on the system, but ramoops fails to attach to
> it, the module parameters are overridden before ramoops can fall back and
> try to use passed module parameters. Move update to end of init routine.

Modifying the module paremeters in this way seems like a Wrong Thing To
Do and a rather nasty hack.

I'd have thought that /sys/module/ramoops/parameters should reflect the
options which were provided to the module and should not be modified by
the kernel behind everyone's back.

If we wish to display the configuration which the driver acquired from
the platform data then sure, add an interface to do that.  But it's
wrong to go and pretend that this is what the user provided to
modprobe!