[LTP] [PATCH v2 1/1] splice07: Whitelist /dev/zero on pipe write

[LTP] [PATCH v2 1/1] splice07: Whitelist /dev/zero on pipe write

[Petr Vorel]

/dev/zero on pipe write started to succeeded on kernel 6.7.

This is due commit 1b057bd800c3 ("drivers/char/mem: implement splice()
for /dev/zero, /dev/full") from kernel 6.7.

Suggested-by: Cyril Hrubis <chrubis@suse.cz>
Signed-off-by: Petr Vorel <pvorel@suse.cz>
---
Changes v1->v2:
* Skip only for kernel >= 6.7

 testcases/kernel/syscalls/splice/splice07.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/testcases/kernel/syscalls/splice/splice07.c b/testcases/kernel/syscalls/splice/splice07.c
index 135c42e47..c7b1c9ee5 100644
--- a/testcases/kernel/syscalls/splice/splice07.c
+++ b/testcases/kernel/syscalls/splice/splice07.c
@@ -44,6 +44,10 @@ static void check_splice(struct tst_fd *fd_in, struct tst_fd *fd_out)
 		/* And this complains about socket not being connected */
 		case TST_FD_INET_SOCK:
 			return;
+		/* 1b057bd800c3 implemented splice() for /dev/zero, /dev/full */
+		case TST_FD_DEV_ZERO:
+			if (tst_kvercmp(6, 7, 0) >= 0)
+				return;
 		default:
 		break;
 		}
-- 
2.43.0


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Re: [LTP] [PATCH v2 1/1] splice07: Whitelist /dev/zero on pipe write

[Martin Doucha]

Hi,
splice() works on /dev/zero and /proc/self/maps on older kernels at 
least between v4.4 and v5.3.

On 26. 01. 24 13:16, Petr Vorel wrote:
> /dev/zero on pipe write started to succeeded on kernel 6.7.
> 
> This is due commit 1b057bd800c3 ("drivers/char/mem: implement splice()
> for /dev/zero, /dev/full") from kernel 6.7.
> 
> Suggested-by: Cyril Hrubis <chrubis@suse.cz>
> Signed-off-by: Petr Vorel <pvorel@suse.cz>
> ---
> Changes v1->v2:
> * Skip only for kernel >= 6.7
> 
>   testcases/kernel/syscalls/splice/splice07.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/testcases/kernel/syscalls/splice/splice07.c b/testcases/kernel/syscalls/splice/splice07.c
> index 135c42e47..c7b1c9ee5 100644
> --- a/testcases/kernel/syscalls/splice/splice07.c
> +++ b/testcases/kernel/syscalls/splice/splice07.c
> @@ -44,6 +44,10 @@ static void check_splice(struct tst_fd *fd_in, struct tst_fd *fd_out)
>   		/* And this complains about socket not being connected */
>   		case TST_FD_INET_SOCK:
>   			return;
> +		/* 1b057bd800c3 implemented splice() for /dev/zero, /dev/full */
> +		case TST_FD_DEV_ZERO:
> +			if (tst_kvercmp(6, 7, 0) >= 0)
> +				return;
>   		default:
>   		break;
>   		}

-- 
Martin Doucha   mdoucha@suse.cz
SW Quality Engineer
SUSE LINUX, s.r.o.
CORSO IIa
Krizikova 148/34
186 00 Prague 8
Czech Republic


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Re: [LTP] [PATCH v2 1/1] splice07: Whitelist /dev/zero on pipe write

[Petr Vorel]

> Hi,
> splice() works on /dev/zero and /proc/self/maps on older kernels at least
> between v4.4 and v5.3.

Yep, this was just a sanity fix before the release to fix mainline.
OK, so we should skip also between v4.4 and v5.3?
Because you're testing it, please post better version.

And we should (as Cyril noted) after release add tests which actually test
splice() on /dev/zero and /proc/self/maps.

Thanks!

Kind regards,
Petr

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Re: [LTP] [PATCH v2 1/1] splice07: Whitelist /dev/zero on pipe write

[Cyril Hrubis]

Hi!
> splice() works on /dev/zero and /proc/self/maps on older kernels at 
> least between v4.4 and v5.3.

My guess would have been that this stopped working after the changes for
set_fs removal, see:

https://lwn.net/Articles/832121/

and kernel commit 36e2c7421f02

The article explicitly cites that splice() stopped working for files
that does not implemente splice_read().

So splice for these two didn't work between 5.10 and 6.7.

-- 
Cyril Hrubis
chrubis@suse.cz

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Re: [LTP] [PATCH v2 1/1] splice07: Whitelist /dev/zero on pipe write

[Martin Doucha]

On 26. 01. 24 15:14, Cyril Hrubis wrote:
> Hi!
>> splice() works on /dev/zero and /proc/self/maps on older kernels at
>> least between v4.4 and v5.3.
> 
> My guess would have been that this stopped working after the changes for
> set_fs removal, see:
> 
> https://lwn.net/Articles/832121/
> 
> and kernel commit 36e2c7421f02
> 
> The article explicitly cites that splice() stopped working for files
> that does not implemente splice_read().
> 
> So splice for these two didn't work between 5.10 and 6.7.

In that case it makes sense to treat /dev/zero and /proc/self/maps as 
unconditionally expected success for splice() to writable pipe.

-- 
Martin Doucha   mdoucha@suse.cz
SW Quality Engineer
SUSE LINUX, s.r.o.
CORSO IIa
Krizikova 148/34
186 00 Prague 8
Czech Republic


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Re: [LTP] [PATCH v2 1/1] splice07: Whitelist /dev/zero on pipe write

[Cyril Hrubis]

Hi!
> In that case it makes sense to treat /dev/zero and /proc/self/maps as 
> unconditionally expected success for splice() to writable pipe.

I suppose so. And ideally we should write a separate test just for that
after the release.

-- 
Cyril Hrubis
chrubis@suse.cz

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Re: [LTP] [PATCH v2 1/1] splice07: Whitelist /dev/zero on pipe write

[Martin Doucha]

On 26. 01. 24 15:26, Cyril Hrubis wrote:
> Hi!
>> In that case it makes sense to treat /dev/zero and /proc/self/maps as
>> unconditionally expected success for splice() to writable pipe.
> 
> I suppose so. And ideally we should write a separate test just for that
> after the release.

+1 to new test.

-- 
Martin Doucha   mdoucha@suse.cz
SW Quality Engineer
SUSE LINUX, s.r.o.
CORSO IIa
Krizikova 148/34
186 00 Prague 8
Czech Republic


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Re: [LTP] [PATCH v2 1/1] splice07: Whitelist /dev/zero on pipe write

[Jan Kara]

On Fri 26-01-24 13:16:03, Petr Vorel wrote:
> /dev/zero on pipe write started to succeeded on kernel 6.7.
> 
> This is due commit 1b057bd800c3 ("drivers/char/mem: implement splice()
> for /dev/zero, /dev/full") from kernel 6.7.
> 
> Suggested-by: Cyril Hrubis <chrubis@suse.cz>
> Signed-off-by: Petr Vorel <pvorel@suse.cz>

Yeah, makes sense to me. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
> Changes v1->v2:
> * Skip only for kernel >= 6.7
> 
>  testcases/kernel/syscalls/splice/splice07.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/testcases/kernel/syscalls/splice/splice07.c b/testcases/kernel/syscalls/splice/splice07.c
> index 135c42e47..c7b1c9ee5 100644
> --- a/testcases/kernel/syscalls/splice/splice07.c
> +++ b/testcases/kernel/syscalls/splice/splice07.c
> @@ -44,6 +44,10 @@ static void check_splice(struct tst_fd *fd_in, struct tst_fd *fd_out)
>  		/* And this complains about socket not being connected */
>  		case TST_FD_INET_SOCK:
>  			return;
> +		/* 1b057bd800c3 implemented splice() for /dev/zero, /dev/full */
> +		case TST_FD_DEV_ZERO:
> +			if (tst_kvercmp(6, 7, 0) >= 0)
> +				return;
>  		default:
>  		break;
>  		}
> -- 
> 2.43.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

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Re: [LTP] [PATCH v2 1/1] splice07: Whitelist /dev/zero on pipe write

[Petr Vorel]

Hi,

just for a record in the end we decided to merge v1.

https://lore.kernel.org/ltp/20240125155107.430656-1-pvorel@suse.cz/
https://lore.kernel.org/ltp/Zbd44afh7ytamDuA@yuki/

Kind regards,
Petr

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