[PATCH bpf 1/1] selftests/bpf: Enable BLK_DEV_NBD for raw_tp_writable_reject_nbd_invalid

[PATCH bpf 1/1] selftests/bpf: Enable BLK_DEV_NBD for raw_tp_writable_reject_nbd_invalid

[Shung-Hsi Yu]

The raw_tp_writable_reject_nbd_invalid test relies on availability of the
nbd_send_request tracepoint, which is only present if the selftest kernel is
built with CONFIG_BLK_DEV_NBD=y and the kernel built from current BPF selftests
config lacks.

Without it, the bpf_raw_tracepoint_open() call always returns with -2, leaving
raw_tp_writable_reject_nbd_invalid test always passing without exercising the
checks bpf_probe_register().

Cc: <stable@vger.kernel.org> # 5.2.0
Link: https://lore.kernel.org/bpf/alRtilWhKw4zzMkI@u94a
Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
Not sure if fixes tag is the right thing to use here, so use the cc
stable tag instead to get this config change propogated to other stable
branches to make stable BPF CI's job easier.
---
 tools/testing/selftests/bpf/config | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config
index adb25146e88c..e1797bd87904 100644
--- a/tools/testing/selftests/bpf/config
+++ b/tools/testing/selftests/bpf/config
@@ -1,4 +1,5 @@
 CONFIG_BLK_DEV_LOOP=y
+CONFIG_BLK_DEV_NBD=y
 CONFIG_BOOTPARAM_HARDLOCKUP_PANIC=y
 CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC=1
 CONFIG_BPF=y
-- 
2.54.0

Re: [PATCH bpf 1/1] selftests/bpf: Enable BLK_DEV_NBD for raw_tp_writable_reject_nbd_invalid

[sun jian]

On Mon, Jul 13, 2026 at 2:35 PM Shung-Hsi Yu <shung-hsi.yu@suse.com> wrote:
>
>
> The raw_tp_writable_reject_nbd_invalid test relies on availability of the
> nbd_send_request tracepoint, which is only present if the selftest kernel is
> built with CONFIG_BLK_DEV_NBD=y and the kernel built from current BPF selftests
> config lacks.
>
> Without it, the bpf_raw_tracepoint_open() call always returns with -2, leaving
> raw_tp_writable_reject_nbd_invalid test always passing without exercising the
> checks bpf_probe_register().
>
> Cc: <stable@vger.kernel.org> # 5.2.0
> Link: https://lore.kernel.org/bpf/alRtilWhKw4zzMkI@u94a
> Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
> ---
> Not sure if fixes tag is the right thing to use here, so use the cc
> stable tag instead to get this config change propogated to other stable
> branches to make stable BPF CI's job easier.
> ---
>  tools/testing/selftests/bpf/config | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config
> index adb25146e88c..e1797bd87904 100644
> --- a/tools/testing/selftests/bpf/config
> +++ b/tools/testing/selftests/bpf/config
> @@ -1,4 +1,5 @@
>  CONFIG_BLK_DEV_LOOP=y
> +CONFIG_BLK_DEV_NBD=y
>  CONFIG_BOOTPARAM_HARDLOCKUP_PANIC=y
>  CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC=1
>  CONFIG_BPF=y
> --
> 2.54.0
>

I tested this on bpf/master at 7cbd0c4cebe4. With the patch
applied, CONFIG_BLK_DEV_NBD=y and the nbd_send_request
tracepoint was present. raw_tp_writable_reject_nbd_invalid
passed, and strace showed BPF_RAW_TRACEPOINT_OPEN failing
with EINVAL rather than ENOENT.

Tested-by: Sun Jian <sun.jian.kdev@gmail.com>

Re: [PATCH bpf 1/1] selftests/bpf: Enable BLK_DEV_NBD for raw_tp_writable_reject_nbd_invalid

[Eduard Zingerman]

On Mon, 2026-07-13 at 14:35 +0800, Shung-Hsi Yu wrote:
> 
> The raw_tp_writable_reject_nbd_invalid test relies on availability of the
> nbd_send_request tracepoint, which is only present if the selftest kernel is
> built with CONFIG_BLK_DEV_NBD=y and the kernel built from current BPF selftests
> config lacks.
> 
> Without it, the bpf_raw_tracepoint_open() call always returns with -2, leaving
> raw_tp_writable_reject_nbd_invalid test always passing without exercising the
> checks bpf_probe_register().
> 
> Cc: <stable@vger.kernel.org> # 5.2.0
> Link: https://lore.kernel.org/bpf/alRtilWhKw4zzMkI@u94a
> Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
> ---
> Not sure if fixes tag is the right thing to use here, so use the cc
> stable tag instead to get this config change propogated to other stable
> branches to make stable BPF CI's job easier.

Shung-Hsi,

Thank you for figuring this out.
I'd suggest we switch to bpf_testmod_test_writable_bare_tp() [1]
from the test module to avoid the config dependency and let
Sun pack all of this as a single patch-set to simplify backports
(if such are necessary). Wdyt?

[1] https://lore.kernel.org/bpf/3430dc0a2a141769a596ab21d7abdd86a0a804db.camel@gmail.com/2-tp-test.diff

Re: [PATCH bpf 1/1] selftests/bpf: Enable BLK_DEV_NBD for raw_tp_writable_reject_nbd_invalid

[Shung-Hsi Yu]

On Mon, Jul 13, 2026 at 01:47:18PM -0700, Eduard Zingerman wrote:
> On Mon, 2026-07-13 at 14:35 +0800, Shung-Hsi Yu wrote:
> > The raw_tp_writable_reject_nbd_invalid test relies on availability of the
> > nbd_send_request tracepoint, which is only present if the selftest kernel is
> > built with CONFIG_BLK_DEV_NBD=y and the kernel built from current BPF selftests
> > config lacks.
> > 
> > Without it, the bpf_raw_tracepoint_open() call always returns with -2, leaving
> > raw_tp_writable_reject_nbd_invalid test always passing without exercising the
> > checks bpf_probe_register().
> > 
> > Cc: <stable@vger.kernel.org> # 5.2.0
> > Link: https://lore.kernel.org/bpf/alRtilWhKw4zzMkI@u94a
> > Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
> > ---
> > Not sure if fixes tag is the right thing to use here, so use the cc
> > stable tag instead to get this config change propogated to other stable
> > branches to make stable BPF CI's job easier.
> 
> Shung-Hsi,
> 
> Thank you for figuring this out.
> I'd suggest we switch to bpf_testmod_test_writable_bare_tp() [1]
> from the test module to avoid the config dependency and let
> Sun pack all of this as a single patch-set to simplify backports
> (if such are necessary). Wdyt?

Make sense, that's probably for the better.

pw-bot: changes-requested

@Sun can you make sure to include the follow tag for [1] when you send
it? Should give a better guarantee that is will be picked up by AUTOSEL.
Thanks!

  Cc: <stable@vger.kernel.org> # 5.2.0

Re: [PATCH bpf 1/1] selftests/bpf: Enable BLK_DEV_NBD for raw_tp_writable_reject_nbd_invalid

[sun jian]

On Tue, Jul 14, 2026 at 11:32 AM Shung-Hsi Yu <shung-hsi.yu@suse.com> wrote:
>
> On Mon, Jul 13, 2026 at 01:47:18PM -0700, Eduard Zingerman wrote:
> > On Mon, 2026-07-13 at 14:35 +0800, Shung-Hsi Yu wrote:
> > > The raw_tp_writable_reject_nbd_invalid test relies on availability of the
> > > nbd_send_request tracepoint, which is only present if the selftest kernel is
> > > built with CONFIG_BLK_DEV_NBD=y and the kernel built from current BPF selftests
> > > config lacks.
> > >
> > > Without it, the bpf_raw_tracepoint_open() call always returns with -2, leaving
> > > raw_tp_writable_reject_nbd_invalid test always passing without exercising the
> > > checks bpf_probe_register().
> > >
> > > Cc: <stable@vger.kernel.org> # 5.2.0
> > > Link: https://lore.kernel.org/bpf/alRtilWhKw4zzMkI@u94a
> > > Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
> > > ---
> > > Not sure if fixes tag is the right thing to use here, so use the cc
> > > stable tag instead to get this config change propogated to other stable
> > > branches to make stable BPF CI's job easier.
> >
> > Shung-Hsi,
> >
> > Thank you for figuring this out.
> > I'd suggest we switch to bpf_testmod_test_writable_bare_tp() [1]
> > from the test module to avoid the config dependency and let
> > Sun pack all of this as a single patch-set to simplify backports
> > (if such are necessary). Wdyt?
>
> Make sense, that's probably for the better.
>

Hi Shung-Hsi and Eduard,

Thanks for tracking down the CONFIG_BLK_DEV_NBD false
pass and for the test-module suggestion.

I'll fold everything into the v5 series:

1. Keep only the necessary effective-start check in the verifier fix,
dropping the BPF_MAX_VAR_OFF and size < 0 checks as Eduard suggested.
2. Move the attach tests to bpf_testmod_test_writable_bare_tp(), use
subtests, and remove the NBD configuration dependency.
3. Add the PTR_TO_BUF negative-offset verifier case requested by Eduard.

> pw-bot: changes-requested
>
> @Sun can you make sure to include the follow tag for [1] when you send
> it? Should give a better guarantee that is will be picked up by AUTOSEL.
> Thanks!
>
>   Cc: <stable@vger.kernel.org> # 5.2.0

Will do.

Best Regards,
Sun Jian