diff mbox series

[06/12] nouveau: fix function cast warning

Message ID 20240326145140.3257163-5-arnd@kernel.org (mailing list archive)
State New
Headers show
Series kbuild: enable some -Wextra warnings by default | expand

Commit Message

Arnd Bergmann March 26, 2024, 2:51 p.m. UTC 
From: Arnd Bergmann <arnd@arndb.de>

Calling a function through an incompatible pointer type causes breaks
kcfi, so clang warns about the assignment:

drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowof.c:73:10: error: cast from 'void (*)(const void *)' to 'void (*)(void *)' converts to incompatible function type [-Werror,-Wcast-function-type-strict]
   73 |         .fini = (void(*)(void *))kfree,

Avoid this with a trivial wrapper.

Fixes: c39f472e9f14 ("drm/nouveau: remove symlinks, move core/ to nvkm/ (no code changes)")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowof.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

Comments

Timur Tabi March 26, 2024, 3:20 p.m. UTC | #1 
On Tue, 2024-03-26 at 15:51 +0100, Arnd Bergmann wrote:
> Calling a function through an incompatible pointer type causes breaks
> kcfi, so clang warns about the assignment:
> 

...

> +static void of_fini(void *p)
> +{
> +       return kfree(p);
> +}
> +

I don't know anything about kfci, but shouldn't this just be "kfree(p)",
without the "return"?
Arnd Bergmann March 26, 2024, 4:02 p.m. UTC | #2 
On Tue, Mar 26, 2024, at 16:20, Timur Tabi wrote:
> On Tue, 2024-03-26 at 15:51 +0100, Arnd Bergmann wrote:
>> Calling a function through an incompatible pointer type causes breaks
>> kcfi, so clang warns about the assignment:
>> 
>
> ...
>
>> +static void of_fini(void *p)
>> +{
>> +       return kfree(p);
>> +}
>> +
>
> I don't know anything about kfci, but shouldn't this just be "kfree(p)",
> without the "return"?

You are right, fixed this up locally now, waiting for more
comments before I resend patches from my series.

I think it works because of a gcc extension, but isn't
valid C otherwise, and I did not mean to rely on this.

     Arnd
diff mbox series

Patch

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowof.c b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowof.c
index 4bf486b57101..0dbcc23305f3 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowof.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowof.c
@@ -66,11 +66,16 @@  of_init(struct nvkm_bios *bios, const char *name)
 	return ERR_PTR(-EINVAL);
 }
 
+static void of_fini(void *p)
+{
+	return kfree(p);
+}
+
 const struct nvbios_source
 nvbios_of = {
 	.name = "OpenFirmware",
 	.init = of_init,
-	.fini = (void(*)(void *))kfree,
+	.fini = of_fini,
 	.read = of_read,
 	.size = of_size,
 	.rw = false,