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dyndbg: fix module.dyndbg handling

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For CONFIG_DYNAMIC_DEBUG=N, the ddebug_dyndbg_module_param_cb()
stub-fn is too permissive:

bash-5.1# modprobe drm JUNKdyndbg
bash-5.1# modprobe drm dyndbgJUNK
[   42.933220] dyndbg param is supported only in CONFIG_DYNAMIC_DEBUG builds
[   42.937484] ACPI: bus type drm_connector registered

This caused no ill effects, because unknown parameters are either
ignored by default with an "unknown parameter" warning, or ignored
because dyndbg allows its no-effect use on non-dyndbg builds.

But since the code has an explicit feedback message, it should be
issued accurately.  Fix with strcmp for exact param-name match.

Fixes: b48420c1d301 dynamic_debug: make dynamic-debug work for module initialization
Reported-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Jason Baron <jbaron@akamai.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Link: https://lore.kernel.org/r/20220904214134.408619-3-jim.cromie@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jim Cromie 2022-09-04 15:40:39 -06:00 committed by Greg Kroah-Hartman
parent ee879be38b
commit 85d6b66d31
1 changed files with 1 additions and 1 deletions
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2
include/linux/dynamic_debug.h
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@ -201,7 +201,7 @@ static inline int ddebug_remove_module(const char *mod)
static inline int ddebug_dyndbg_module_param_cb(char *param, char *val,
const char *modname)
{
if (strstr(param, "dyndbg")) {
if (!strcmp(param, "dyndbg")) {
/* avoid pr_warn(), which wants pr_fmt() fully defined */
printk(KERN_WARNING "dyndbg param is supported only in "
"CONFIG_DYNAMIC_DEBUG builds\n");