[PATCH] Fix implicit cast warning in test_klp_state.c

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Re: [PATCH] Fix implicit cast...

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Shresth Prasad

16 Feb 2024 16 Feb '24

10:51 p.m.

The function `klp_get_state` returns an `int` value, but the variable `loglevel_state` is of type `struct klp_state *` and thus does an implicit cast. Explicitly casting these values fixes:

- warning: assignment to ‘struct klp_state *’ from ‘int’ makes pointer from integer without a cast [-Wint-conversion]

on lines 38, 55, 68 and 80 of test_klp_state.c

Signed-off-by: Shresth Prasad shresthprasad7@gmail.com --- .../selftests/livepatch/test_modules/test_klp_state.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/livepatch/test_modules/test_klp_state.c b/tools/testing/selftests/livepatch/test_modules/test_klp_state.c index 57a4253acb01..ae6b1ca15fc0 100644 --- a/tools/testing/selftests/livepatch/test_modules/test_klp_state.c +++ b/tools/testing/selftests/livepatch/test_modules/test_klp_state.c @@ -35,7 +35,7 @@ static int allocate_loglevel_state(void) { struct klp_state *loglevel_state;

- loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); + loglevel_state = (struct klp_state *)klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); if (!loglevel_state) return -EINVAL;

@@ -52,7 +52,7 @@ static void fix_console_loglevel(void) { struct klp_state *loglevel_state;

- loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); + loglevel_state = (struct klp_state *)klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); if (!loglevel_state) return;

@@ -65,7 +65,7 @@ static void restore_console_loglevel(void) { struct klp_state *loglevel_state;

- loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); + loglevel_state = (struct klp_state *)klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); if (!loglevel_state) return;

@@ -77,7 +77,7 @@ static void free_loglevel_state(void) { struct klp_state *loglevel_state;

- loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); + loglevel_state = (struct klp_state *)klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); if (!loglevel_state) return;

-- 2.43.1

Show replies by date

Marcos Paulo de Souza

19 Feb 19 Feb

2:16 p.m.

On Sat, 17 Feb 2024 04:21:26 +0530 Shresth Prasad shresthprasad7@gmail.com wrote:

...

The function `klp_get_state` returns an `int` value, but the variable
`loglevel_state` is of type `struct klp_state *` and thus does an
implicit cast. Explicitly casting these values fixes:

        - warning: assignment to \u2018struct klp_state *\u2019 from \u2018int\u2019
   makes pointer from integer without a cast [-Wint-conversion]

on lines 38, 55, 68 and 80 of test_klp_state.c

I was unable to find where you saw the klp_get_state returning int. I tried searching at the current master of live-patching repo[1], on linux-next. Can you point where do you saw it? For me, klp_get_state return a pointer to klp_state.

Thanks, Marcos

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching.gi...

...

Signed-off-by: Shresth Prasad shresthprasad7@gmail.com

.../selftests/livepatch/test_modules/test_klp_state.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/livepatch/test_modules/test_klp_state.c b/tools/testing/selftests/livepatch/test_modules/test_klp_state.c index 57a4253acb01..ae6b1ca15fc0 100644 --- a/tools/testing/selftests/livepatch/test_modules/test_klp_state.c +++ b/tools/testing/selftests/livepatch/test_modules/test_klp_state.c @@ -35,7 +35,7 @@ static int allocate_loglevel_state(void) { struct klp_state *loglevel_state;

loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);

loglevel_state = (struct klp_state *)klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); if (!loglevel_state) return -EINVAL;

@@ -52,7 +52,7 @@ static void fix_console_loglevel(void) { struct klp_state *loglevel_state;

loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);

loglevel_state = (struct klp_state *)klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); if (!loglevel_state) return;

@@ -65,7 +65,7 @@ static void restore_console_loglevel(void) { struct klp_state *loglevel_state;

loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);

loglevel_state = (struct klp_state *)klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); if (!loglevel_state) return;

@@ -77,7 +77,7 @@ static void free_loglevel_state(void) { struct klp_state *loglevel_state;

loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);

loglevel_state = (struct klp_state *)klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); if (!loglevel_state) return;

2.43.1

zhang warden

20 Feb 20 Feb

6:06 a.m.

Well, the repo location I use is git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git. It seem klp_get_state return struct klp_state. The definition of this function in my repo as follows:

struct klp_state *klp_get_state(struct klp_patch *patch, unsigned long id) { struct klp_state *state;

klp_for_each_state(patch, state) { if (state->id == id) return state; }

return NULL; } EXPORT_SYMBOL_GPL(klp_get_state);

Are you sure there is really a need for forced conversion?

...

2024年2月19日 22:16，Marcos Paulo de Souza mpdesouza@suse.com 写道：

On Sat, 17 Feb 2024 04:21:26 +0530 Shresth Prasad shresthprasad7@gmail.com wrote:

...
The function `klp_get_state` returns an `int` value, but the variable `loglevel_state` is of type `struct klp_state *` and thus does an implicit cast. Explicitly casting these values fixes:
       - warning: assignment to \u2018struct klp_state *\u2019 from \u2018int\u2019
makes pointer from integer without a cast [-Wint-conversion]

on lines 38, 55, 68 and 80 of test_klp_state.c
I was unable to find where you saw the klp_get_state returning int. I tried searching at the current master of live-patching repo[1], on linux-next. Can you point where do you saw it? For me, klp_get_state return a pointer to klp_state.

Thanks, Marcos

...
Signed-off-by: Shresth Prasad shresthprasad7@gmail.com

.../selftests/livepatch/test_modules/test_klp_state.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/livepatch/test_modules/test_klp_state.c b/tools/testing/selftests/livepatch/test_modules/test_klp_state.c index 57a4253acb01..ae6b1ca15fc0 100644 --- a/tools/testing/selftests/livepatch/test_modules/test_klp_state.c +++ b/tools/testing/selftests/livepatch/test_modules/test_klp_state.c @@ -35,7 +35,7 @@ static int allocate_loglevel_state(void) { struct klp_state *loglevel_state;

loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);

loglevel_state = (struct klp_state *)klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);

if (!loglevel_state) return -EINVAL;

@@ -52,7 +52,7 @@ static void fix_console_loglevel(void) { struct klp_state *loglevel_state;

loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);

loglevel_state = (struct klp_state *)klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);

if (!loglevel_state) return;

@@ -65,7 +65,7 @@ static void restore_console_loglevel(void) { struct klp_state *loglevel_state;

loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);

loglevel_state = (struct klp_state *)klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);

if (!loglevel_state) return;

@@ -77,7 +77,7 @@ static void free_loglevel_state(void) { struct klp_state *loglevel_state;

loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);

loglevel_state = (struct klp_state *)klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE);

if (!loglevel_state) return;

-- 2.43.1

Shresth Prasad

11:53 a.m.

Looking at the function definition now, I do see that the function returns a struct pointer but for me the compiler still complains about an implicit conversion from int to struct pointer.

Is there any particular reason why this might be happening? I couldn't quite figure it out myself as I am very new to working with the kernel.

Regards, Shresth

Marcos Paulo de Souza

noon

On Tue, 20 Feb 2024 17:23:49 +0530 (GMT+05:30) Shresth Prasad shresthprasad7@gmail.com wrote:

...

Looking at the function definition now, I do see that the function returns a struct pointer but for me the compiler still complains about an implicit conversion from int to struct pointer.

Is there any particular reason why this might be happening? I couldn't quite figure it out myself as I am very new to working with the kernel.

What compiler version and architecture? Are you compiling using flags like W=1? I would advise you to always add more information about how the problem manifests, and what you are executing. This can help to nail down the issue quicker.

Thanks, Marcos

...

Regards, Shresth

Shresth Prasad

1:20 p.m.

...

What compiler version and architecture? Are you >compiling using flags like W=1? I would advise you to always add more information >about how the problem manifests, and what you are executing. This can >help to nail down the issue quicker.

I'll keep that in mind. I'm on an x86_64 system with gcc version 13.2.1 20230801.

I'm using the command `make -j15 -C tools/testing/selftests` with no additional flags.

Regards, Shresth

zhang warden

21 Feb 21 Feb

2:38 a.m.

Would you please pasting the original warning of your complier? And did you check your source code if your source code is the the latest version?

Regards, Warden

...

On Feb 20, 2024, at 21:20, Shresth Prasad shresthprasad7@gmail.com wrote:

...
What compiler version and architecture? Are you >compiling using flags like W=1? I would advise you to always add more information >about how the problem manifests, and what you are executing. This can >help to nail down the issue quicker.

I'll keep that in mind. I'm on an x86_64 system with gcc version 13.2.1 20230801.

I'm using the command `make -j15 -C tools/testing/selftests` with no additional flags.

Regards, Shresth

Shresth Prasad

9:59 a.m.

I checked the source code and yes I am on the latest Linux next repo.

Here's the warning: /home/shresthp/dev/linux_work/linux_next/tools/testing/selftests/livepatch/test_modules/test_klp_state.c:38:24: warning: assignment to ‘struct klp_state *’ from ‘int’ makes pointer from integer without a cast [-Wint-conversion] 38 | loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); | ^ /home/shresthp/dev/linux_work/linux_next/tools/testing/selftests/livepatch/test_modules/test_klp_state.c: In function ‘fix_console_loglevel’: /home/shresthp/dev/linux_work/linux_next/tools/testing/selftests/livepatch/test_modules/test_klp_state.c:55:24: warning: assignment to ‘struct klp_state *’ from ‘int’ makes pointer from integer without a cast [-Wint-conversion] 55 | loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); | ^ /home/shresthp/dev/linux_work/linux_next/tools/testing/selftests/livepatch/test_modules/test_klp_state.c: In function ‘restore_console_loglevel’: /home/shresthp/dev/linux_work/linux_next/tools/testing/selftests/livepatch/test_modules/test_klp_state.c:68:24: warning: assignment to ‘struct klp_state *’ from ‘int’ makes pointer from integer without a cast [-Wint-conversion] 68 | loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); | ^ /home/shresthp/dev/linux_work/linux_next/tools/testing/selftests/livepatch/test_modules/test_klp_state.c: In function ‘free_loglevel_state’: /home/shresthp/dev/linux_work/linux_next/tools/testing/selftests/livepatch/test_modules/test_klp_state.c:80:24: warning: assignment to ‘struct klp_state *’ from ‘int’ makes pointer from integer without a cast [-Wint-conversion] 80 | loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); | ^

Thank you for your help so far.

Regards, Shresth

Nicolai Stange

12:44 p.m.

Shresth Prasad shresthprasad7@gmail.com writes:

...

I checked the source code and yes I am on the latest Linux next repo.

Here's the warning: /home/shresthp/dev/linux_work/linux_next/tools/testing/selftests/livepatch/test_modules/test_klp_state.c:38:24: warning: assignment to ‘struct klp_state *’ from ‘int’ makes pointer from integer without a cast [-Wint-conversion] 38 | loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); | ^

Is the declaration of klp_get_state() visible at that point, i.e. is there perhaps any warning about missing declarations above that?

Otherwise C rules would default to assume an 'int' return type.

Thanks,

Nicolai

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Shresth Prasad

22 Feb 22 Feb

8:12 a.m.

...

Is the declaration of klp_get_state() visible at that >point, i.e. is there perhaps any warning about missing >declarations above that?

Otherwise C rules would default to assume an 'int' >return type.

I wasn't aware it works like that. You're right I do see some warnings about implicit function declarations of klp_get_state.

Regards, Shresth

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Marcos Paulo de Souza
Nicolai Stange
Shresth Prasad
zhang warden