[PATCH RESEND bpf v2 0/2] x86/bpf: Fixes for the BPF JIT with retbleed=stuff

Uros Bizjak
2024-04-01T18:58:37Z

From: Joan Bruguera Micó <joanbrugueram@gmail.com>

Fixes two issues that cause kernels panic when using the BPF JIT with
the call depth tracking / stuffing mitigation for Skylake processors
(`retbleed=stuff`). Both issues can be triggered by running simple
BPF programs (e.g. running the test suite should trigger both).

The first (resubmit) fixes a trivial issue related to calculating the
destination IP for call instructions with call depth tracking.

The second is related to using the correct IP for relocations, related
to the recently introduced %rip-relative addressing for PER_CPU_VAR.

Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
---
v2:
Simplify calculation of "ip".
Add more details to the commit message.

Joan Bruguera Micó (1):
x86/bpf: Fix IP for relocating call depth accounting

Uros Bizjak (1):
x86/bpf: Fix IP after emitting call depth accounting

arch/x86/include/asm/alternative.h | 4 ++--
arch/x86/kernel/callthunks.c | 4 ++--
arch/x86/net/bpf_jit_comp.c | 19 ++++++++-----------
3 files changed, 12 insertions(+), 15 deletions(-)

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2.42.0