Re: [PATCH bpf-next v7 0/9] bpf: add support for KASAN checks in JITed programs

["Kumar Kartikeya Dwivedi" <memxor@gmail.com>]

On Sat Aug 22, 2026 at 12:39 AM CEST, Alexis Lothoré (eBPF Foundation) wrote:
> Hello,
> this is v7 of the series aiming to bring basic support for KASAN checks
> to BPF JITed programs. This new revision just makes the series rebased
> on top of current bpf-next_base.
>
> Please note that with the recent kernel splat detector introduced in
> kernel-patches/vmtest through commit 8109e5928cd0 ("ci: own the kernel
> splat matching (#509)"), CI runs on this series will fail with the
> following error.
>
>    Error: kernel splat detected: [  100.689549] BUG: KASAN: \
>    slab-use-after-free in \
>    bpf_prog_eba69524d1d949b1_st_not_on_stack+0x12f/0x17a \
>
> which is pretty normal, as the new selftests introduced by this series
> are expected to trigger KASAN splats (the test_progs part will pass,
> only the kernel_splats part will trigger errors). The right fix may be
> to just put a list of regex matching all the kasan subtests progs in the
> relevant SPLAT_ALLOWLIST file; something like:
>
> BUG: KASAN: slab-(out-of-bounds|use-after-free) in bpf_prog_([a-f0-9]){16}_(st|ld)(x)?(_not)?_on_stack\+
> BUG: KASAN: slab-(out-of-bounds|use-after-free) in bpf_prog_([a-f0-9]){16}_simple_atomic(_fetch)?(_not)_on_stack\+
> BUG: KASAN: slab-(out-of-bounds|use-after-free) in bpf_prog_([a-f0-9]){16}_ldx_patched(_not)?_on_stack\+
> BUG: KASAN: slab-(out-of-bounds|use-after-free) in bpf_prog_([a-f0-9]){16}_verifier_paths_stack_and_non_stack\+
> BUG: KASAN: slab-(out-of-bounds|use-after-free) in bpf_prog_([a-f0-9]){16}_ldx_oob\+
> BUG: KASAN: slab-(out-of-bounds|use-after-free) in bpf_prog_([a-f0-9]){16}_st_blinded\+
> BUG: KASAN: slab-(out-of-bounds|use-after-free) in bpf_prog_([a-f0-9]){16}_(load_acquire|store_release)(_not)?_on_stack\+
>
> I can take care of opening the relevant PR in kernel-patches/vmtest with
> this if it ends up being the correct solution, but it will make sense to
> do so only once the selftests list is validated (but before merging the
> series).

We need to resolve this before landing the set. To me it looks inevitable, esp.
if we exercise the support and produce such warnings. That said I'll let Ihor
respond and provide guidance for this. We should probably land the vmtest PR
before v8 is posted, so that v8 can go through CI and be processed without
failures.

> [...]