On 8/31/22 10:27 PM, Zhen Lei wrote:
> The patch->mod is not a protected object of mutex_lock(&klp_mutex). Since
> it's in the error handling branch, it might not be helpful to reduce lock
> conflicts, but it can reduce some code size.
>
> Before:
> text data bss dec hex filename
> 10330 464 8 10802 2a32 kernel/livepatch/core.o
>
> After:
> text data bss dec hex filename
> 10307 464 8 10779 2a1b kernel/livepatch/core.o
>
Is a size change expected, or is it just compiler fall out from
shuffling the code around a little bit?
I see some arches do a little better, some a little worse with gcc-9.3.0
cross compilers:
Before
------
text data bss dec hex filename
8490 600 8 9098 238a arm64/kernel/livepatch/core.o
9424 680 8 10112 2780 s390/kernel/livepatch/core.o
9802 228 4 10034 2732 ppc32/kernel/livepatch/core.o
13746 456 8 14210 3782 ppc64le/kernel/livepatch/core.o
10443 464 8 10915 2aa3 x86_64/kernel/livepatch/core.o
After
-----
text data bss dec hex filename
8514 600 8 9122 23a2 arm64/kernel/livepatch/core.o
9424 680 8 10112 2780 s390/kernel/livepatch/core.o
9818 228 4 10050 2742 ppc32/kernel/livepatch/core.o
13762 456 8 14226 3792 ppc64le/kernel/livepatch/core.o
10446 464 8 10918 2aa6 x86_64/kernel/livepatch/core.o
In which case, I'd just omit the size savings from the commit msg.
> Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
> ---
> kernel/livepatch/core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
> index 42f7e716d56bf72..cb7abc821a50584 100644
> --- a/kernel/livepatch/core.c
> +++ b/kernel/livepatch/core.c
> @@ -1041,9 +1041,9 @@ int klp_enable_patch(struct klp_patch *patch)
> mutex_lock(&klp_mutex);
>
> if (!klp_is_patch_compatible(patch)) {
> + mutex_unlock(&klp_mutex);
> pr_err("Livepatch patch (%s) is not compatible with the already installed livepatches.\n",
> patch->mod->name);
> - mutex_unlock(&klp_mutex);
> return -EINVAL;
> }
>
>
That said, I don't see anything obviously wrong about the change (we
don't need to sync our error msgs, right?) so:
Acked-by: Joe Lawrence <joe.lawrence@xxxxxxxxxx>
--
Joe
