Re: [PATCH bpf-next v3 1/4] bpf: crypto: Use the correct destructor kfunc type

Hi Viktor,

On Fri, Nov 21, 2025 at 8:06 AM Viktor Malik [off-list ref] wrote:

On 7/28/25 22:26, Sami Tolvanen wrote:

quoted

With CONFIG_CFI_CLANG enabled, the kernel strictly enforces that
indirect function calls use a function pointer type that matches the
target function. I ran into the following type mismatch when running
BPF self-tests:

  CFI failure at bpf_obj_free_fields+0x190/0x238 (target:
    bpf_crypto_ctx_release+0x0/0x94; expected type: 0xa488ebfc)
  Internal error: Oops - CFI: 00000000f2008228 [#1]  SMP
  ...

As bpf_crypto_ctx_release() is also used in BPF programs and using
a void pointer as the argument would make the verifier unhappy, add
a simple stub function with the correct type and register it as the
destructor kfunc instead.

Hi,

this patchset got somehow forgotten and I'd like to revive it.

We're hitting kernel oops when running the crypto cases from test_progs
(`./test_progs -t crypto`) on CPUs with IBT (Indirect Branch Tracking)
support. I managed to reproduce this on the latest bpf-next, see the
relevant part of dmesg at the end of this email.

After applying this patch, the oops no longer happens.

It looks like the series is stuck on a sparse warning reported by kernel
test robot, which seems like a false positive. Could we somehow resolve
it and proceed with reviewing and merging this?

I agree, it does look like a false positive.

Since this resolves our issue, adding my tested-by:

Tested-by: Viktor Malik <redacted>

Thanks for testing! I can resend this series when I have a chance to
put it back in the review queue. The CFI config option also changed
from CONFIG_CFI_CLANG to just CONFIG_CFI since this was sent, so the
commit message could use an update too.

Sami