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| author | Nuoqi Gui <gnq25@mails.tsinghua.edu.cn> | 2026-06-18 01:50:27 +0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-06-21 17:51:58 -0700 |
| commit | a93ae7ed5972fa4cf7c0244395dc1bcc7e0016be (patch) | |
| tree | 871595a03aad4ec99205d74de580638e089f4238 /tools/testing/selftests | |
| parent | d1d53aa30ab3b5ae89161c9cc840b3f7489ad386 (diff) | |
| download | lwn-a93ae7ed5972fa4cf7c0244395dc1bcc7e0016be.tar.gz lwn-a93ae7ed5972fa4cf7c0244395dc1bcc7e0016be.zip | |
selftests/bpf: Cover stack nospec slot indexing
Add a verifier test for the fixed-offset stack write case where two 4-byte
stores initialize opposite halves of the same stack slot.
The test runs through the unprivileged loader lane and expects both
half-slot writes to emit nospec in the translated program.
Acked-by: Luis Gerhorst <luis.gerhorst@fau.de>
Signed-off-by: Nuoqi Gui <gnq25@mails.tsinghua.edu.cn>
Link: https://lore.kernel.org/r/20260618-f01-11-stack-nospec-slot-index-v3-2-780297041721@mails.tsinghua.edu.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools/testing/selftests')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/verifier_unpriv.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/verifier_unpriv.c b/tools/testing/selftests/bpf/progs/verifier_unpriv.c index c16f8382cf17..49f7bd05edad 100644 --- a/tools/testing/selftests/bpf/progs/verifier_unpriv.c +++ b/tools/testing/selftests/bpf/progs/verifier_unpriv.c @@ -976,4 +976,26 @@ l0_%=: exit; \ : __clobber_all); } +SEC("socket") +__description("unpriv: Spectre v4 stack write slot index") +__success __success_unpriv +__retval(0) +#ifdef SPEC_V4 +__xlated_unpriv("r0 = 0") +__xlated_unpriv("*(u32 *)(r10 -4) = r0") +__xlated_unpriv("nospec") +__xlated_unpriv("*(u32 *)(r10 -8) = r0") +__xlated_unpriv("nospec") +__xlated_unpriv("exit") +#endif +__naked void stack_write_nospec_slot_index(void) +{ + asm volatile (" \ + r0 = 0; \ + *(u32 *)(r10 - 4) = r0; \ + *(u32 *)(r10 - 8) = r0; \ + exit; \ +" ::: __clobber_all); +} + char _license[] SEC("license") = "GPL"; |