From 02b2fb455b2e80a0a831d067ab7ef950e2991eee Mon Sep 17 00:00:00 2001 From: zhouchuangao Date: Wed, 12 May 2021 07:01:57 -0700 Subject: [PATCH 1/2] kernel/module: Use BUG_ON instead of if condition followed by BUG Fix the following coccinelle report: kernel/module.c:1018:2-5: WARNING: Use BUG_ON instead of if condition followed by BUG. BUG_ON uses unlikely in if(). Through disassembly, we can see that brk #0x800 is compiled to the end of the function. As you can see below: ...... ffffff8008660bec: d65f03c0 ret ffffff8008660bf0: d4210000 brk #0x800 Usually, the condition in if () is not satisfied. For the multi-stage pipeline, we do not need to perform fetch decode and excute operation on brk instruction. In my opinion, this can improve the efficiency of the multi-stage pipeline. Signed-off-by: zhouchuangao Signed-off-by: Jessica Yu --- kernel/module.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/kernel/module.c b/kernel/module.c index b5dd92e35b02a7..faf9114a9981c1 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1014,8 +1014,7 @@ void __symbol_put(const char *symbol) }; preempt_disable(); - if (!find_symbol(&fsa)) - BUG(); + BUG_ON(!find_symbol(&fsa)); module_put(fsa.owner); preempt_enable(); } From 2c0f0f3639562d6e38ee9705303c6457c4936eac Mon Sep 17 00:00:00 2001 From: Jon Mediero Date: Thu, 20 May 2021 14:23:26 +0200 Subject: [PATCH 2/2] module: correctly exit module_kallsyms_on_each_symbol when fn() != 0 Commit 013c1667cf78 ("kallsyms: refactor {,module_}kallsyms_on_each_symbol") replaced the return inside the nested loop with a break, changing the semantics of the function: the break only exits the innermost loop, so the code continues iterating the symbols of the next module instead of exiting. Fixes: 013c1667cf78 ("kallsyms: refactor {,module_}kallsyms_on_each_symbol") Reviewed-by: Petr Mladek Reviewed-by: Miroslav Benes Signed-off-by: Jon Mediero Signed-off-by: Jessica Yu --- kernel/module.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/module.c b/kernel/module.c index faf9114a9981c1..fdd6047728df83 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -4415,9 +4415,10 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *, ret = fn(data, kallsyms_symbol_name(kallsyms, i), mod, kallsyms_symbol_value(sym)); if (ret != 0) - break; + goto out; } } +out: mutex_unlock(&module_mutex); return ret; }