[lkml]   [2018]   [Nov]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH v3 09/23] dynamic_debug: use pointer comparison in ddebug_remove_module
Now that we store the passed-in string directly in ddebug_add_module, we
can use pointer equality instead of strcmp. This is a little more
efficient, but more importantly, this also makes the code somewhat more

Currently, if one loads and then unloads a module whose name happens to
match the KBUILD_MODNAME of some built-in functionality (which need not
even be modular at all), all of their dynamic debug entries vanish along
with those of the actual module. For example, loading and unloading a
core.ko hides all pr_debugs from drivers/base/core.c and other built-in
files called core.c (incidentally, there is an in-tree module whose name
is core, but I just tested this with an out-of-tree trivial one).

Acked-by: Jason Baron <>
Signed-off-by: Rasmus Villemoes <>
lib/dynamic_debug.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 2155e0e23530..ab81155f928d 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -929,9 +929,10 @@ int ddebug_remove_module(const char *mod_name)

list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
- if (!strcmp(dt->mod_name, mod_name)) {
+ if (dt->mod_name == mod_name) {
ret = 0;
+ break;
 \ /
  Last update: 2018-11-10 00:13    [W:0.200 / U:36.492 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site