[PATCH] io_uring: initialize vairable "sqe" to silence build warning

[PATCH] io_uring: initialize vairable "sqe" to silence build warning

[Mallikarjun Thammanavar]

clang-17 compiler throws build error when [-Werror,-Wuninitialized] are enabled
error: variable 'sqe' is uninitialized when used here [-Werror,-Wuninitialized]

Initialize struct io_uring_sqe *sqe = NULL; to have clean build
Reported-by: kernelci.org bot <bot@kernelci.org>
Link: https://lore.kernel.org/regressions/176110914348.5309.724397608932251368@15dd6324cc71/

Signed-off-by: Mallikarjun Thammanavar <mallikarjunst09@gmail.com>
---
 io_uring/fdinfo.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/io_uring/fdinfo.c b/io_uring/fdinfo.c
index d5aa64203de5..e5792b794f8b 100644
--- a/io_uring/fdinfo.c
+++ b/io_uring/fdinfo.c
@@ -89,7 +89,7 @@ static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m)
 	seq_printf(m, "CachedCqTail:\t%u\n", data_race(ctx->cached_cq_tail));
 	seq_printf(m, "SQEs:\t%u\n", sq_tail - sq_head);
 	while (sq_head < sq_tail) {
-		struct io_uring_sqe *sqe;
+		struct io_uring_sqe *sqe = NULL;
 		unsigned int sq_idx;
 		bool sqe128 = false;
 		u8 opcode;
-- 
2.34.1

Re: [PATCH] io_uring: initialize vairable "sqe" to silence build warning

[Greg KH]

On Wed, Oct 22, 2025 at 05:07:16PM +0200, Mallikarjun Thammanavar wrote:
> clang-17 compiler throws build error when [-Werror,-Wuninitialized] are enabled
> error: variable 'sqe' is uninitialized when used here [-Werror,-Wuninitialized]
> 
> Initialize struct io_uring_sqe *sqe = NULL; to have clean build
> Reported-by: kernelci.org bot <bot@kernelci.org>
> Link: https://lore.kernel.org/regressions/176110914348.5309.724397608932251368@15dd6324cc71/
> 
> Signed-off-by: Mallikarjun Thammanavar <mallikarjunst09@gmail.com>
> ---
>  io_uring/fdinfo.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/io_uring/fdinfo.c b/io_uring/fdinfo.c
> index d5aa64203de5..e5792b794f8b 100644
> --- a/io_uring/fdinfo.c
> +++ b/io_uring/fdinfo.c
> @@ -89,7 +89,7 @@ static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m)
>  	seq_printf(m, "CachedCqTail:\t%u\n", data_race(ctx->cached_cq_tail));
>  	seq_printf(m, "SQEs:\t%u\n", sq_tail - sq_head);
>  	while (sq_head < sq_tail) {
> -		struct io_uring_sqe *sqe;
> +		struct io_uring_sqe *sqe = NULL;

If you do that, then other tools will report a NULL dereference, right?

Please fix the tools, don't paper over stuff like this.

thanks,

greg k-h

Re: [PATCH] io_uring: initialize vairable "sqe" to silence build warning

[Jens Axboe]

On 10/22/25 9:07 AM, Mallikarjun Thammanavar wrote:
> clang-17 compiler throws build error when [-Werror,-Wuninitialized] are enabled
> error: variable 'sqe' is uninitialized when used here [-Werror,-Wuninitialized]

Already fixed, and as Greg mentioned, this may silence the warning but now it'll
cause a NULL pointer deref instead...

-- 
Jens Axboe

Re: [PATCH] io_uring: initialize vairable "sqe" to silence build warning

[Mallikarjun S T]

Thanks, Greg and Jens, for pointing this out.

I understand that this issue has already been fixed, and I’ll make
sure to pay closer attention in future submissions.

regards,
Mallikarjun